METHODS AND NUCLEIC ACID SEQUENCES FOR THE EXPRESSION OF THE CELLULOSE SYNTHASE OPERON

Abstract: Nucleic acid sequences encoding the bacterial cellulose synthase operon derived from Acetobacter are disclosed. Methods for isolating the genes, vectors containing the genes, and transformed hosts useful for the expression of recombinant bacterial cellulose synthase or production of cellulose are also described.

Description: METHODS AND NUCLEIC ACID SEQUENCES FOR THE EXPRESSION OF THE CELLULOSE SYNTHASE OPERON Technical Field of the Invention The invention relates to the field of recombinant DNA techniques for the production of proteins. More specifically, this invention relates to the cloning of the bacterial cellulose synthase operon, the expression of this operon and methods of using this operon for the production of cellulose in recombinant microorganisms. Background of the Invention Cellulose is relied upon as the raw material for a number of useful products including paper products and wound dressings. Cellulose may be obtained from plants and various microorganisms in culture, for example from the cellulose producing bacteria of the genus Acetobacter■ Acetobacter is characteristically a Gram-negative, rod-shaped bacterium 0.6-0.8 u by 1.0-4 um. It is strictly aerobic; metabolism is respiratory, never fermentative. It is further distinguished by the ability to produce multiple poly β(l-4)-glucan chains, chemically identical to cellulose. Multiple cellulose chains or microfibrils are synthesized at the bacterial surface at sites on the cell wall. The production of cellulose by Acetobacter has been the subject of intense study since at least the 1930"s. In particular, Acetobacter xylinum has been widely studied to attempt to elucidate the mechanism of cellulose synthesis in intact cells [Schramm and Hestrin,(1954) J. Gen. Microbiol. 11:123-129]. The enzymatic pathway for cellulose synthesis in Acetobacter xylinum has been investigated and essentially four enzymatic steps have been characterized in cell-free extracts of A. xylinum which appear to comprise the complete pathway from glucose to cellulose. These are the phosphorylation of glucose by glucokinase [Benziman, et al. , (1972) J. Bacteriol. , 111:325-330], the isomerization of glucose-6-phosphate to glucose-1-phosphate by phos- phogluco utase [Gromet, et al., (1957) Biochem. J., 67:679-689; Frei-Roitman, Factors affecting the activity of phosphoglucomutase and UDP-glucose pyrophosphorylase of Acetobacter xylinum, M.Sc. thesis, The Hebrew University of Jerusalem, Jerusalem, Israel (1974)]; the synthesis of uridine 5'-diphosphoglucose (UDP-glc) by UDPG- pyrophosphorylase, [Frei-Roitman, supra; Swissa, Biosynthesis * of cellulose in Acetobacter xylinum, Ph.D. thesis, The He/brew University of Jerusalem, Jerusalem, Israel (1978)3, and the cellulose synthase reaction. Attempts to purify cellulose synthase from a strain of A. xylinum employing conventional chromatographic techniques have not been especially successful, but recently the enzyme has been significantly purified (P. Ross and M. Benziman (1989) in Biosynthesis and Biodegradation of Cellulose and Cellulose Materials, eds. Weimar and Higler, Marcel Dekker, Inc. NY, in press), and its properties and structure in the purified state are currently under investigation. Similarly, attempts to purify cellulose synthase by in vitro cellulose entrapment and chromatographic techniques have resulted in a partially purified 83 kilodalton (kd) polypeptide (Lin and Brown, The Tenth Cellulose Conference, May 29-June 2, 1988, Abstract BG1, page 27) . Although the physiological role of cellulose synthesis in this organism is still not clear, considering that at least 10% of the cell's energy budget is devoted to cellulose production at any one time [Weinhouse, Regulation of Carbohydrate metabolism in Acetobacter xylinum, Ph.D. thesis. The Hebrew University of Jerusalem, Jerusalem, Israel (1977)], it is not surprising that the biosynthetic system is governed by a complex regulatory system. Cellulose synthase, the only enzyme unique to the pathway, performs the "committed" step in cellulose formation - a metabolic dead-end with regard to carbon utilization - and hence would logically be the prime candidate for strict regulatory control. Furthermore, as demonstrated in cell-free extracts, the level of enzyme activities leading to UDP-glc are in large excess relative to that of the cellulose synthase, strongly supporting the proposition that the latter comprises the rate-limiting step in cellulose biosynthesis. A more complete knowledge of the biochemistry of cellulose synthesis would facilitate greater productivity and yield of cellulose from cultures of cellulose-producing microorganisms. The growth of bacterial cells in culture is observed to be initially exponential but slows as the cells enter a stationary growth phase. The majority of cellulose is produced later in fermentation when the number of cells is highest, however the amount of cellulose made per cell per unit time (specific productivity) declines as the fermentation proceeds. It is believed that cellulose 98 - 4 - synthase activity may be rate limiting as cells in culture reach the stationary growth phase. One improvement in cellulose production would be to remove a rate-limiting step in cellulose synthesis, thereby preventing the observed decline in cellulose specific productivity in culture. • Recombinant DNA techniques are now routinely available for production of desired proteins. However, to take advantage of such recombinant DNA techniques, the gene coding for the desired protein, such as cellulose synthase, must first be isolated. This task is considerable, especially when the primary sequence of the encoded protein is unknown and known assays for determining cellulose synthase activity are difficult. The ability to produce recombinant cellulose synthase provides an important tool useful in exploring the mechanisms of cellulose synthesis, ultimately providing enhanced cellulose production from bacterial culture. Summary of the Invention The present invention provides an operon associated with the biosynthesis of cellulose, polynucleotides encoding one or more closely linked genes that code for proteins of bacterial cellulose synthase, expression vectors suitable for production of cellulose synthase, recombinant host cells transformed with these vectors, methods for producing bacterial cellulose synthase, and methods to increase the production of cellulose in a recombinant microorganism. More particularly the invention provides an isolated native, cloned recombinant or synthetic polynucleotide encoding the bacterial cellulose synthase operon characterized by the polycistronic - 5 - nucleotide sequence shown in Figure 1. The cellulose synthase operon is approximately 9217 basepairs (bp) in length and comprises four genes, designated herein as "A", "B", "C", and "D". The invention further provides a process for expressing cellulose synthase in a host cell comprising transforming the host cell with a recombinant DNA expression vector comprising one or more of the genes associated with the bacterial cellulose synthase operon, which gene(s) is operably linked to a control sequence for expression of bacterial cellulose synthase, and culturing the transformed host cell under conditions suitable for expression of cellulose synthase. The expression vector constructions of the present invention can either replicate independently or may be designed so as to introduce a heterologous promoter into the Acetobacter chromosome, thereby replacing the native cellulose synthase operon promoter. Yet another aspect of the invention provides a method for increasing cellulose production in a recombinant microorganism, which method comprises transforming a suitable microorganism with a vector comprising at least one gene derived from the cellulose synthase operon, and culturing the transformed microorganism under conditions suitable for production of cellulose. As discussed above, the chromosomal cellulose synthase promoter can be replaced with a heterologous promoter to overexpress the cellulose synthase operon at the chromosomal level. A further aspect of the invention provides the individual proteins encoded by the cellulose synthase operon. The isolated recombinant cellulose synthase B protein is capable of synthesizing β(l-4)-glucan polymers from uridine 5'-diphosphoglucose, whereas the - 6 - protein encoded by gene A is capable of complementing cellulose negative Acetobacter cells defective in both cellulose synthase and diguanylate cyclase activities. The protein encoded by either gene C or D is capable of synthesizing β(l-4)-glucan polymers from uridine 5'-diphosphoglucose and secreting the product from the cells in vivo when the respective protein is combined in appropriate proportions with the other three proteins of the cellulose synthase operon. Also provided are novel recombinant DNA vectors for the expression of heterologous genes in Acetobacter, which vectors comprise a functional Acetobacter origin of replication-containing fragment of plasmid p824, and one or more DNA segments that convey resistance to at least one antibiotic when transformed into a sensitive host cell that is susceptible to transformation, cell division and culture. These vectors may also be developed into shuttle vectors for use in cloning DNA in bacterial host cells, such as E. coli. Brief Description of the Drawings Figure 1 is the nucleic acid sequence and deduced amino acid sequence of the cellulose synthase operon. The cellulose synthase operon is approximately 9217 bp in length and consists of four genes, a 2261 nucleotide sequence designated A (nucleotides 328-2589), a 2405 nucleotide sequence designated B (nucleotides 2594-4999), a 3956 nucleotide sequence designated C (nucleotides 5005 to 8961) and a 467 nucleotide sequence designated D (nucleotides 8964 to 9431. The nucleotide sequences of each gene provided herein may include signal sequences. The mature protein encoded by its respective gene may have undergone processing and if so, the corresponding gene sequence will be shorter than that provided above. For example, the alanine codon which corresponds to the first amino acid of the purified cellulose synthase B protein is flanked by two upward arrows, tt. The site of transcription initiation is designated by a downward arrow, , positioned over the A at nucleotide 235. The underlined nucleotide sequence following gene D designates the transcription terminator region comprising an inverted repeat sequence characteristic of stem-and-loop structures. The sequence of oligonucleotide MK170 is indicated above nucleotides 2190 to 2210, and that of MK172 is indicated above nucleotides 4564 to 4583. Figure 2 depicts the construction of cosmid vector pKT230cos5. Figure 3 is an illustration of the construction of TRT18-1 which contains the full-length cellulose synthase B gene. Figure 4 is a restriction map of plasmid pUC18-824. Figure 5 is a restriction map of the 8.3 kb Smal fragment and the 7.2 kb BamHI fragment from cosmid T5A1. Figure 6 is a restriction and functional map of plasmid pUC18-824 FS6; pUC18-824 FSl is homologous to pUC18-824 FS6 except the orientation of the Smal restriction fragment carrying the cellulose synthase gene is reversed. Figure 7 is a restriction and functional map of plasmid pUC19-824. Figure 8 schematically illustrates the construc¬ tion of plasmid pABCD. Figure 9 is a flow chart describing the construction of expression vectors containing - 8 - heterologous promoters to transcribe the genes of the cellulose synthase operon. Detailed Description of the Invention In order that the invention herein described may be more fully understood, the following detailed description is set forth. A. Definitions As used herein, the term "cellulose synthase" refers to one or more polypeptides associated in the in vivo biochemical conversion of uridine 5'-diphosphoglucose to bacterial cellulose and secretion outside of the cell. A single transcriptional unit containing four genes associated with the synthesis of cellulose synthase is encoded by the nucleic acid sequence provided in Figure 1. The term "cellulose synthase gene" is defined as a nucleic acid sequence encoding a polypeptide product associated with, the cellulose synthase operon. The term is not limited to any Acetobacter bacterial strain or species. "Cellulose synthase operon," as used herein, refers to a stretch of DNA sequence which codes for a group of protein products associated with cellulose synthesis and secretion outside of the cell. Optionally, the operon may include transcriptional elements such as a promoter region and a transcription terminator region which regulate the expression of the genes encoding the proteins. "Cellulose synthase activity" is defined by the ability to synthesize cellulose [β(l-4)-glucan] from UDP-glc. This activity is measured in vitro by incorporation of UDP-( 1 C) glucose to cellulose (base insoluble) and is measured as nmole (nanomole) of glucose incorporated to cellulose per min. - 9 - "Cellulose synthase specific activity" is defined as nmole glucose incorporated to cellulose/ min/mg protein. Cellulose synthase specific activity in Acetobacter cells is normally ranged from 0.2 to 4.0 nmole glc/min/mg cell protein. As used herein, the term "Acetobacter" refers to a genus of microorganisms, and in particular, to members of that genus which produce cellulose. "Suitable microorganism" refers to a microorganism which is capable of producing cellulose when transformed with one or more of the genes associated with the cellulose synthase operon. Suitable microorganisms include those host cells which are capable of cellulose production in the absence of transformation, or those host cells which are deficient in one or more of the genes whose activity may be replaced by at least one gene of the cellulose synthase operon. "Operably linked" refers to a juxtaposition such that the normal function of the components can be performed. Thus, a coding sequence "operably linked" to control sequences refers to a configuration wherein the coding sequences can be expressed under the control of these sequences. Such control may be direct, that is, a single gene associated with a single promoter, or indirect, as in the case where a polycistronic transcript is expressed from a single promoter. "Control sequence" refers to a DNA sequence or sequences necessary for the expression of an operably linked coding sequence in a particular host organism. The control sequences which are suitable for procaryotes, for example, include a promoter, optionally an operator sequence, a ribosome binding site, a transcription terminator, and possibly other as - 10 - yet poorly understood sequences. Eucaryotic cells are known to utilize promoters, polyadenylation signals, and enhancers. "Cells" or "recombinant host cells" or "host cells" are often used interchangeably, and all such designation include progeny. Thus, "transformants" or "transformed cells" includes the primary subject cell and cultures derived therefrom without regard for the number of transfers. It is also understood that all progeny may not be precisely identical in DNA content, due to deliberate or inadvertent mutations. .Mutant progeny which have the same functionality as screened for in the originally transformed cell are included. Where distinct designations are intended, it will be clear from the context. As used herein, a polynucleotide "derived from" a designated sequence, for example, the DNA from the cellulose synthase B gene, refers to a polynucleotide sequence which is comprised of a sequence of at least 6-20 nucleotides, more preferably at least 15 to 20 nucleotides corresponding, i.e., identical to or complementary to, a region of the designated nucleotide sequence. The correspondence to the nucleic acid sequence will be approximately 70% or greater, will preferably be at least 80%, and even more preferably will be at least 90%. The correspondence or non-correspondence of the derived sequence to other sequences can be determined by hybridization under the appropriate stringency conditions, using standard DNA hybridization technologies in liquid phases or on solid supports. Hybridization techniques for determining the complementarity of nucleic acid sequences are known in the art (see, for example, Sambrook et al. (1989) Molecular Cloning: A Laboratory Manual, Second - 11 - Edition, Cold Spring Harbor Press, Cold Spring Harbor, NY). In addition, mismatches of duplex polynucleotides formed by hybridization can be determined by known techniques, including digestion with a nuclease such as SI, that specifically digests single-stranded sequences in duplex polynucleotides. The derived polynucleotide is not necessarily physically derived from the nucleotide sequence shown, but may be generated in any manner, including for example, chemical synthesis, DNA replication or reverse transcription, which methods are based on the information provided by the sequence of bases in the region(s) from which the polynucleotide is derived. Similarly, a polypeptide "derived from" a designated sequence, for example, from cellulose synthase B, refers to a polypeptide having an amino acid sequence identical to that of a polypeptide encoded in the sequence, or a protein thereof wherein the portion consists of at least 5-10 amino acids, and more preferably at least 10-15 amino acids, which is immunologically identifiable with a polypeptide encoded in the sequence, or exhibits similar biological activity as that of the reference protein in the in vitro or In vivo assays described herein. As used herein with reference to an amino acid sequence "substantial correspondence" refers to a sequence usually differing by fewer than 10 amino acids, more usually differing by fewer than 5 amino acids. The recombinant protein, whether "A", "B", "C" or "D", displays substantially the same biological properties as the naturally occurring protein. The biological properties include immunological properties, where antibodies raised to the authentic protein cross-react with the recombinant protein. The term "recombinant polypeptide" as used herein to characterize a polypeptide useful for the production of cellulose synthase intends a polypeptide encoded by genomic, cDNA, semisynthetic, or synthetic nucleic acid sequences which, by virtue of their origin or manipulation: (1) are not associated with all or a portion of the polynucleotide with which they are associated in nature or in the form of a library; and/or (2) are linked to a polynucleotide other than that to which it is linked in nature. "Expression system" refers to DNA sequences containing a desired coding sequence and control sequences in operable linkage, so that hosts transformed with these sequences are capable of producing the encoded proteins. In order to effect transformation, the expression system may be included on a vector; however, the relevant DNA may also be integrated into the host chromosome. "Sensitive host cell" refers to a host cell that cannot grow in the presence of a given antibiotic without a DNA segment containing a gene that confers resistance thereto. As used herein, the term "vector" refers to a polynucleotide suitable for transferring nucleic acid sequences into a host cell. The term may include plas- mids, mini-chromosomes, phage, naked DNA and the like. B. General Description The methods illustrated below to obtain one or more DNA sequences encoding genes of the bacterial cellulose synthase operon are merely for purposes of illustration and are typical of those that might be used. However, once the genes have been identified, other procedures may also be employed, as is understood in the art. - 13 - Obtaining The Coding Sequences For The Bacterial Cellulose Synthase Operon The polynucleotide encoding the bacterial cellulose synthase operon was obtained from an Acetobacter DNA library, as set forth in the examples, and genetic complementation was used to identify the genes. The procedures for obtaining the nucleotide sequence encoding the bacterial cellulose synthase operon employ a number of individual steps that required adaptation for Acetobacter DNA, and include (1) preparation and characterization of cellulose negative (Cel ) mutant Acetobacter strains; (2) construction of appropriate vectors for cloning; (3) construction of an Acetobacter DNA library; (4) identification and isolation of DNA insert sequences capable of restoring cellulose synthase activity in the Cel" Acetobacter mutants; (5) mapping and subcloning of the nucleotide sequences encoding the bacterial cellulose synthase operon for both sequence analysis and localization of the cellulose synthase coding sequences; and (6) cloning and expression of the DNA encoding the products of the cellulose synthase operon. Confirmation of the cloned sequence may be performed by comparing the N-terminal amino acid sequence of the recombinantly produced bacterial cellulose synthase with that purified from a native Acetobacter source. In addition, the amino acid sequence deduced from the cloned nucleotide sequence may be compared with the primary sequence of a protein obtained from a native Acetobacter source and purified. Attempts to clone the gene encoding cellulose synthase were initially directed at the identification of the B gene. While the cellulose synthase B gene has been cloned and sequenced, the interpretation of the 5' end of this gene was complicated for a variety of reasons. For example, the transcriptional and translational signals in Acetobacter are not characterized and control signals similar or analogous to those known for E. coli control signals were not present in the upstream region of the codon for alanine (the N-terminal residue of the purified native protein). However, the proximity of an open reading frame upstream of this gene suggested that this gene was part of a polycistronic mess-age. Therefore, additional studies to sequence the open reading frames both upstream and downstream of this gene were performed as described herein. These studies revealed the identity of four closely linked genes bounded at the 5' end by a single promoter and at the 3' end by a transcription terminator region. While the precise function of each of these gene products has not been confirmed, complementation studies indicate that strains that are defective in cellulose synthase activity can be complemented by gene B, and that cellulose negative mutants that were defective in both cellulose synthase and diguanylate cyclase activities are complemented by gene A. Cellulose negative class III mutants are complemented by a DNA fragment that codes for genes C and D. The mutants in this group make cellulose in vitro and have all the * enzymatic activities necessary for cellulose production. Gene D encodes a protein that is associated with cellulose synthesis. Disruption of this gene significantly reduces cellulose synthesis. Genes A, C and D may code for regulatory, structural, membrane bound or processing proteins required in cellulose synthesis in vivo. The availability of coding sequences for their respective gene product permits the synthesis of large amounts of each protein for studies to further elucidate the mechanism of cellulose synthesis. Expression of Bacterial Cellulose Synthase According to one method of the invention, the polynucleotide encoding the cellulose synthase operon may be cloned into an appropriate vector, transformed into a suitable microorganism host and cultured under conditions which permit the expression of cellulose synthase. Alternatively, given the sequence identity of each gene in this operon, each gene may be independently cloned and expressed to produce the desired gene product. Transcription of the polynucleotide sequences encoding the cellulose synthase operon gene products may be performed using the endogenous Acetobacter promoter or, alternatively, may be driven by heterologous bacterial promoters, including those derived from E. coli or B. subtilis. Many of the heterologous promoters described herein, such as the lac, trp and- tac are regulated promoters and are therefore useful in the method of the invention to control the expression of the bacterial cellulose synthase operon. However, promoters such as the PL promoters, which are regulated by temperature sensitive repressors, i.e., nonfunctional beyond 37 β C would not be operable in many Acetobacter strains since these strains are normally cultured at 35°C or lower and would not grow beyond this temperature range. Regulation of the heterologous promoters may utilize either positive or negative control elements. For example, a gene encoding a repressor which recognizes an operator associated with a heterologous promoter (e.g., the lad repressor) may be introduced into the host system. Alternatively, the level of tryptophan present in growth media can provide for regulation of the trp promoter. Yet another means to control expression of the cellulose synthase operon may employ a heterologous transcription terminator to stabilize the mRNA transcript. For example, the transcriptional terminator isolated from the crystal protein of B. thuringienesis has been shown to increase the expression level of many proteins in E. coli -and in B. subtilis by stabilizing their mRNAs. Similarly, it is believed that this terminator, or other such terminators, may be used to increase the mRNA level from the cellulose synthase operon in Acetobacter. It is expected that the increased mRNA levels will enhance cellulose synthesis in the recombinant Acetobacter strains. The resulting constructions may be inserted into a suitable, cellulose-producing microorganism and either replicated independently using an appropriate expression vector or, if plasmid instability is thought to be a problem, the promoter-gene construct may be integrated directly into the chromosome of the host microorganism. The cellulose-producing host microorganism may be either a cellulose synthase negative strain or a cellulose synthase positive strain. In the former example, one or more of the genes of the cellulose synthase operon will restore the cellulose producing ability of the host microorganism. It is expected in the latter example that the introduction of the recombinant cellulose synthase operon will increase both the cellulose synthase activity and cellulose production of the recombinant strain. Replacement of the chromosomal cellulose synthase operon promoter with heterologous bacterial promoters has several advantages over a plasmid system designed to overexpress cellulose synthase. Chromosomal promoter replacement avoids any potential problems which may be due to plasmid instability. It also removes the need for an antibiotic to maintain plasmid selection. Lastly, chromosomal promoter replacement removes the control of the operon from Acetobacter, allowing for a stronger, constitutive promoter or providing for control using a regulated promoter. The nucleotide sequence encoding the genes of the bacterial cellulose synthase operon of the invention may be expressed in a variety of procaryotic systems, including E. coli, Strepto yces, Acetobacter, Aqrobacteria, Rhizobium, Pseudomonas, Alcaligenes, Zymomonas, Zooqloea, blue-green algae, and Sarcina ventricculi, with E. coli and Acetobacter being preferred. Since cellulose synthase is of bacterial origin, vectors suitable for the expression of cellulose synthase are known in the art and may include hybrid shuttle vectors for the development of host-vector systems for acetic acid bacteria, such as Acetobacter. Fukaya, et al., (1985) Aqric. Biol. Chem. 49:2083-2090, describe several shuttle vectors of relatively small size, with selectable antibiotic gene markers, and capable of replicating in E. coli and Acetobacter■ Fukaya, et al., (1989) App. Env. Microbiol. 55:171-176, describe a shuttle vector for E. coli and Acetobacter species, pmv24, which allows translation of a cloned sequence as a fusion protein with β-galactosidase. - 18 - The present invention also provides an endogenous Acetobacter vector for use in the cloning and expression of the cellulose synthase genes. This vector, called p824, is small, and lacks the large mobilization region present on the pKT230cos5 conjugation vector described herein. The small size of p824 makes it easier to manipulate as a cloning vector. Analysis of the insert DNA in this vector should also be greatly facilitated due to its small size. The p824 vector can be used to directly clone genes from one Acetobacter host to another, thereby eliminating the host restriction barrier and associated rearrangements/deletions that occur during conjugation of pKT230cos5 cosmids from E. coli to Acetobacter. The endogenous plasmid may be used for direct Acetobacter-Acetobacter transfer and may also be used to develop shuttle vectors. Thus, the present invention also provides both cloning and expression vectors (for E. coli and Acetobacter species), using appropriate control sequences which allow direct transcription and translation of a desired sequence using, for example, the E. coli lac promoter and its translational initiation signal. Transformation of Acetobacter with these vectors results in transformation efficiencies useful for various types of cloning and expression experiments. Protein Recovery Purification of the recombinant cellulose synthase is accomplished using procedures similar to those used to recover the native material. Generally the cultured cells are disrupted using mechanical or enzymatic means, for example using a French Press, sonication or treatment with lysozyme and EDTA, and then collected by centrifugation to recover the pellet containing the cellulose synthase activity. The pellet is resuspended and centrifuged to remove soluble protein and the collected pellet is solubilized with detergent, for example, with digitonin or Triton X-100 with 20% glycerol. Optionally, one may concentrate the desired activity using ultrafiltration or centrifugation. The enzyme is entrapped using cellulose, its own insoluble product, to separate the enzyme from other detergent-solubilized proteins. The entrapped enzyme may than be recovered from the cellulose by digestion of the cellulose with pure cellulase. Standard Methods Most of the techniques which are used to transform cells, construct vectors, achieve complementation and the like are widely practiced in the art, and most practitioners are familiar with the standard resource materials which describe specific conditions and procedures (see for example, Sambrook, et al., (1989). In addition. Miller, J.M. (1972) Experiments in Molecular Genetics, Cold Spring Harbor, NY, provides general procedures useful for conjugation experiments with bacteria. However, for convenience, the following paragraphs may serve as a guideline. Control Sequences And Corresponding Hosts Procaryotes most frequently are represented by various strains of E. coli. However, other microbial strains may also be used, such as bacilli, for example, Bacillus subtilis, various species of Acetobacter, Pseudomonas and Streptomyces. In such procaryotic systems, vectors which contain replication sites and control sequences derived from a species compatible with the host are used. For example, E. coli may be transformed using derivatives of a vector such as pKT230, available from the American Type Culture Collection (ATCC), Rockville, MD (ATCC. No. 37294), and described by Bagdasarian, et al., (1981) Gene ljj:237-247 or by using derivatives of pBR322, a plasmid derived from an E. coli species and described by Bolivar, et al., (1977) Gene 2:95. Plasmid pKT230 has a broad host range origin of replication, an E. coli origin of replication, tra genes necessary for conjugation, and a streptomycin resistance marker. Plasmid pBR322 contains genes for ampicillin and tetracycline resistance, and thus provides additional markers which can be either retained or destroyed in constructing the desired vector. Commonly used procaryotic control sequences which are defined herein to include promoters for transcription initiation, optionally with an operator, along with ribosome binding site sequences, include such commonly used promoters as the beta-lactamase (penicillinase) and lactose (lac) promoter systems (Chang, et al., (1977) Nature 198:1056), the tryptophan (trp) promoter system (Goeddel, et al., (1980) Nucleic Acids. Res. ' 8:4057), the hybrid tac promoter (De Boer, et al., (1983) Proc. Natl. Acad. Sci. USA 80:21-25), and the lambda derived PL promoter (Shimatake, et al., (1981) Nature 292:128) and N-gene ribosome binding site, which has been made useful as a portable control cassette. U.S. Patent No. 4,711,845, issued 8 December 1987 describes this portable control sequence which comprises the first DNA sequence that is the P promoter operably linked to a second DNA sequence corresponding to the NRBS upstream of a third DNA sequence having at least one restriction site that permits cleavage within six base pairs 3' to the N RBS sequence. U.S. Patent No. 4,666,848, issued 19 May 1987, discloses additional vectors with enhanced expression capabilities useful to express bacterial cellulose synthase. Also useful is the alkaline phosphatase (phoA) system described by Chang, et al., in European Patent Publication No. 196,864, published 8 October 1986 and incorporated herein by reference. While each of these publications provides useful expression systems, any available promoter system compatible with procaryotes can be used. Introduction of DNA into Acetobacter A. Conjugations Conjugation is a technique useful for transferring foreign DNA into a targeted host cell. The cosmid vectors constructed in the present invention are not easily transferred from E. coli for replication in a different bacterial host such as Acetobacter■ In such cases, a helper plasmid, such as pRK2013 (Figurski and Helinski, (1979) Proc. Natl. Acad. Sci. USA 76:1648-1652) may be used to assist in transferring the cosmid vector containing the desired DNA insert from the donor cells into the recipient cells. For conjugation, donor, mobilizing and recipient cells are mixed and mated on plates. Cells which acquire the donor are selected for by growth on plates containing antibiotic to which the transformed recipient cells are resistant. Miller, supra, also discloses a conjugation procedure where nutritional markers are used to select recipient cells. Another conjugation procedure suitable for mass screening is the "multiple spot conjugation method" set forth in detail in Example V, infra. B. Transformations Depending on the host cell used, transformation is done using standard chemical techniques appropriate to such cells or may employ electroporation. The calcium treatment employing calcium chloride, as described by, for example, Cohen, S.N., (1972) Proc. Natl. Acad. Sci. USA 69:2110, is used for procaryotes or other cells which contain substantial cell wall barriers. The disadvantage of the chemical approach with an uncharacterized species is that the chance of success with any one protocol is small; hence, . some experimentation to optimize conditions to obtain meaningful levels of transformants may be required. Recently exposure of bacteria to a strong electrical field has been shown to successfully transform a broad range of bacteria, including Pseudomonas and E. coli. Electroporation as applied to bacteria has been available since 1983 (Shivarova, et al., (1983) Z. Al g. Microbial. 23:595). Dower, et al. , ((1988) Nuc. ' Acid. Res. 16:6127) has demonstrated that the efficiency of electroporation in E. coli can be 10- to 100-fold better than the best levels obtained by chemical means.. Two basic parameters affect the efficiency of electroporation. One is the field force and the other is the time period (pulse duration) over which the field force decays. Operationally, cells experience the field . force (E) in a spectrophotometer-type cuvette, with a constant electrode distance (d) . Thus, the amount of voltage (V) applied to the cuvette determines the field force (E=V/d). Accurate delivery of voltage to the sample occurs if the charge is first stored in a capacitor. The pulse duration, dispersion of the force field, is typically delivered in a logarithmic form and the duration of the decay is determined by a combination of series capacitors and parallel resistors. As demonstrated herein, the optimal field force for the Acetobacter strains used in the present invention varies between 9 and 9.5 KV. A study of pulse duration (RC values) using from 25-100 uF (series) versus 200-1200 ohms demonstrated that 25 uF/750 ohms (=18.75 msec) is optimal for Acetobacter strain 1306-24. The level of transformation obtained (approximately 10 7 transformants/ug) is about 10 -fold higher than that obtained by chemical treatment (Fukaya, et al., (1985) Acrri.' Biol. Chem. 49:2091-2097) . It was also determined that the transformation frequency of DNA prepared form Acetobacter is 10 3 -fold higher than when the DNA is prepared from E. coli. Without wishing to be bound by theory, this species barrier is probably due to endonuclease host restriction activity upon unmodified, possibly unmethylated, E. coli DNA. Methods which reduce this restriction barrier have not been explored herein; however, the restriction barrier can be avoided by developing an Acetobacter-Acetobacter vector as described herein. Construction of Acetobacter DNA Library A DNA library is prepared from Acetobacter by isolating nucleic acid from Acetobacter cells and degrading the RNA in the sample. The recovered DNA is partially digested with an appropriate restriction enzyme such as Sau3A and the DNA is subsequently size fractionated, for example, using a sucrose gradient. A fraction containing a selected size range of molecules is ligated into a cosmid vector, and then conventionally packaged into lambda phage particles. The phage particles are then used to infect a suitable host, such as E. coli. A random number of isolates may be selected to isolate the cosmid DNA to determine the sizes*of the inserted DNA and thereafter, a number of clones sufficient to be representative of the genome are picked, grown and screened. Vector Construction Construction of suitable vectors containing the desired coding and control sequences employ standard ligation and restriction enzyme techniques which are well understood in the art. Isolated plasmids, DNA sequences, or synthesized oligonucleotides are cleaved, tailored, and religated in the form desired. Site-specific DNA cleavage is performed by treating the DNA with the suitable restriction endonuclease(s) under conditions which are generally understood in the art, and the particulars of which are specified by the manufacturer of these commercially available restriction enzymes. See, e.g., New England Biolabs, Product Catalog (New England Biolabs, Beverly, MA). In general, about 1 ug of DNA is cleaved by one unit of enzyme, in about 20 ul of buffer solution. An excess of restriction enzyme is typically used to insure complete digestion of the DNA substrate; however, it may be desirable to carry out partial digestions in which some but not all of the sites of a given restriction enzyme in the DNA are cleaved. Such partial digestions are accomplished by varying the concentration of restriction enzyme or length of time the restriction digestion is carried out. Incubation times of about one hour to two hours at about 37°C are workable, although variations can be tolerated. After each incubation, protein is removed by extraction with phenol/chloroform, and may be followed by ether extraction, and the nucleic acid recovered from aqueous fractions by precipitation with ethanol. If desired, size separation of the cleaved fragments may be performed by polyacrylamide gel or agarose gel electrophoresis using standard techniques. A general description of size separations is found in Methods in Enzymoloqy (1980) 65:499-560; Lawn, et al., (1981) Nuc. Acids Res. 9:6113-6114 and Goeddel, et al., (1980) Nuc. Acids Res. 8:405). Restriction cleaved fragments may be blunt ended by treating with the large fragment of E. coli DNA polymerase I (Klenow) in the presence of the four deoxyribonucleoside triphosphates (dNTPs) using incubation times of about 15 to 25 min at 20° to 25°C in 50 mM Tris pH 7.6, 50 mM NaCl, 6 mM MgCl, 6 mM dTT, about 1 U/ul Klenow and 100 uM dNTPs. The Klenow fragment "fills in" opposite 5' sticky ends but the 3'—>5' exonuclease activity of the enzyme chews back protruding 3' single strands in the absence of a template region. If desired, selective repair can be performed by supplying only one, or selected, dNTPs within the limitations dictated by the nature of the sticky ends. After treatment with Klenow, the mixture is • extracted with phenol/chloroform and ethanol precipitated. Treatment under appropriate conditions with SI nuclease or Bal-31 results in hydrolysis of any single-stranded portion. Synthetic oligonucleotides may be prepared by the triester method of Matteucci, et al., (1981) J. Am. Chem. Soc. 103:3185-3191 or by using automated synthesis methods. Kinasing of single strands prior to annealing or for labeling is achieved using an excess, e.g., approximately 10 units of polynucleotide kinase to 1 nmole substrate in the presence of 50 mM Tris, pH 7.6, 10 mM MgCl2» 5 mM dithiothreitol, and 1-2 mM ATP. If kinasing is for labeling of probe, the ATP will contain high specific activity gamma- 32 P. Ligations are performed in 15-30 ul volumes under the following standard conditions and temperatures: 20 mM Tris-HCl, pH 7.5, 10 mM MgCl, 10 mM DTT, 33 ug/ml BSA, 10 mM-50 mM NaCl, and either 40 uM ATP, 0.01- 0.02 (Weiss) units T4 DNA ligase at 0°C (for "sticky end" ligation) or 1 mM ATP, 0.3-0.6 (Weiss) units T4 DNA ligase at 14 β C (for "blunt end" ligation). Intermolecular "sticky end" ligations are usually performed at 33-100 ug/ml total DNA concentrations (5-100 nM total end concentration).- Intermolecular blunt end ligations (usually employing a 10-30 fold molar excess of inserts) are performed at 1 uM total ends concentration. In vector construction employing "vector fragments", the vector fragment is commonly treated with bacterial alkaline phosphatase (BAP) in order to remove the 5' phosphate and prevent religation of the vector. BAP digestions are conducted at pH 8 in approximately 150 mM Tris, in the presence of Na + and Mg +2 using about 1 unit of BAP per ug of vector at 60°C for about one -hour. In order to recover the nucleic acid fragments, the preparation is extracted with phenol/chloroform and ethanol precipitated. Alternatively, religation can be prevented in vectors which have been double digested by additional restriction enzyme digestion of the unwanted fragments. Modification of DNA Sequences For portions of vectors derived from cDNA or genomic DNA which require sequence modifications, site-specific primer directed mutagenesis is used. This technique is now standard in the art, and is - 27 - conducted using a primer synthetic oligonucleotide complementary to a single stranded phage DNA to be mutagenized except for limited mismatching, representing the desired mutation. Briefly, the synthetic oligonucleotide is used as a primer to direct synthesis of a strand complementary to the phage DNA, and the resulting double-stranded DNA is transformed into a phage-supporting host bacterium. Cultures of the transformed bacteria are plated in top agar, permitting plaque formation from single cells which harbor the phage. Theoretically, 50% of the new plaques will contain the phage having, as a single strand, the mutated form; 50% will have the original sequence. The plaques are transferred to nitrocellulose filters and the "lifts" hybridized with kinased synthetic primer at a temperature which permits hybridization of an exact match, but at which the mismatches with the original strand are sufficient to prevent hybridization. Plaques which hybridize with the probe are then picked and cultured, and the DNA is recovered. Details of site-specific mutation procedures are described below in specific examples. Verification of Construction In the constructions set. forth below, correct ligations for plasmid construction are confirmed by first transforming E. coli strain MM294, or other suitable hosts with the ligation mixture. Successful transformants are selected by ampicillin, tetracycline or other antibiotic resistance or using other markers depending on the mode of plasmid construction, as is understood in the art. Plasmids from the transformants are then prepared according to the method of Clewell, et al., (1969) Proc. Natl. Acad. Sci. USA 62:1159, - 28 - optionally following chloramphenicol (Cm) amplification (Clewell, (1972) J. Bacteriol. 110:667). The isolated DNA is analyzed by restriction and/or sequenced by the dideoxy method of Sanger, et al., (1977) Proc. Natl. Acad. Sci. USA 74:5463 as further described by Messing, et al., (1981) Nuc. Acids Res. 9:309, or by the method of Maxam, et al., (1980) Methods in Enzymoloqy 65:499. In order that the invention described herein may be more fully understood, the following examples are set forth. It should be understood that the examples are for illustrative purposes only and are not. to be construed as limiting the scope of this invention in any manner. Example I Preparation of Cellulose Negative Acetobacter Strains In the following examples a number of culture media were used. Unless otherwise indicated the media were formulated as follows: R20-2 medium has the following composition: Compound * Final Concentration Bacto-peptone 5 g/1 Yeast Extract 5 g/1 a2HP0 5 g/1 Citric Acid 1.15 g/1 Carbon Source As specified (if not specified, 2% glucose) Final pH 5.0 +/- 0.2 Minimal medium R70 (also referred to as Acetobacter Minimal Medium or "AMM"), has the following composition: - 29 - Compound Final Concentration (mM) (NH 4 ) S0 4 25 KH 2 P0 4 7. ,3 MgS0 1. ,0 FeS0 4 0. ,013 C Cl2 0. ,10 Na2Mo0 0. ,001 ZnS0 0. ,006 MnS0 4 0, ,006 CuS0 0. ,0002 pH - 5.0 Glucose 2% or 4% (w/v) unless otherwise specified For all studies using R-70 medium and modifications thereof, the following vitamin mixture was added to the minimal medium at a 100-fold dilution: Vitamin Mixture Compound mq/L Inositol 200 Niacin 40 Pyridoxine HC1 40 Thiamine HC1 40 Ca Pantothenate 40 Riboflavin 20 Para-aminobenzoic acid 20 Folic Acid 0.2 Biotin 0.2 R70-2 medium was a modified form of R70. R70-2 had the following composition: Ingredient Final Concentration (mM) (NH 4 ) 2 S0 4 25 KH 2 P0 4 7.3 Na Citrate 4.0 MgS0 1.0 FeCl 3 0.01 CaCl 0.10 Na2Mo0 O.OOl - 30 - Ingredient Final Concentration (mM) ZnS0 4 O.005 MnS0 4 0.005 CuS0 4 0.001 C0CI2 0.001 NiCl 2 0.001 vitamin mixture 10 ml/liter Glucose as specified (usually 2 or 4%, w/v) final pH = 5.0 + 0.2 Production of Mutant Acetobacter Strains Three tissue culture flasks containing 100 ml R70 + 2% glucose, 2% corn steep liquor E804E (CSL, Corn Products, NJ) medium were inoculated with Acetobacter strain 1306-21 (ATCC No. 53524) (one frozen 2 ml vial to each flask). The flasks were incubated statically for 23 hr at 30°C. The pellicles formed by the Acetobacter cells in culture were asceptically removed with forceps, blended for approximately 15 seconds and filtered through 4 layers of sterile cheesecloth. The cells were washed two times with 0.9% NaCl by centrifugation for 10 min at 7500 rpm, at 4°C. The cells were resuspended in 20 ml 0.9% NaCl and filtered once more through 4 layers of cheesecloth to remove any remaining clumps. Mutagenic conditions were selected to give a cell kill of 95% to 99.9%. The cultures were incubated at 30°C. The mutagen was ethyl methansulfonate (EMS, Sigma, St. Louis, MO). The EMS concentrations ranged from 1% to 2% (v/v) and the incubation times ranged from 60 min to 210 min. Similar conditions were used with Acetobacter strains 1306-3 and 1306-11 (ATCC Nos. 53264 and 53263, respectively). Two procedures were used to isolate the Cel" Acetobacter strains, 1) mutagenesis without expression, and 2) mutagenesis with expression. Mutant Acetobacter Strains From EMS Mutagenesis Without Expression Acetobacter strain 1306-21 was treated with EMS and then directly plated on R20-2 medium to determine percent survival. The plates from the EMS mutagenesis of 1306-21 were examined for potential Cel" colonies as follows. The mutagenized culture was plated and after seven (7) days presumptive Cel" colonies were picked. Cel" mutants may be identified on plates as flat and shiny colonies whereas wild type colonies have a rough, dry appearance. In agitated culture Cel + strains form pellets while Cel " cultures produce a suspension of single cells. The frequency of Cel" colonies was determined to be in the range of from 0.05% to 2.0%. A similar technique was used to isolate Cel" strains from Acetobacter strains 1306-3 and 1306-11 and similar mutation frequencies were observed. Mutant Acetobacter Strains From EMS Mutagenesis ' with Expression Samples (approximately 0.05 ml) of EMS-treated Acetobacter cells (strain 1306-21) were inoculated into tubes (2 ml, R20-2 broth) and allowed to grow as standing cultures, to permit expression of mutated genes. Culture samples were serially diluted and plated on R20-2 plates. After incubation, the colonies were screened for potential Cel" types using the above-described protocol and similar mutation frequencies were obtained. A similar technique was used to isolate Cel" strains from Acetobacter strain 1306-3 and 1306-11. Example II Characterization of Cellulose Negative Acetobacter Strains Cellulose Synthase Activity Assay The cellulose synthase assay used to detect in vitro cellulose synthase activity of Cel" Acetobacter mutant strains was a modification of the procedure described by Aloni, et al., (1982) Proc. Natl. Acad. Sci. USA 79:6448-6452, which measures production of alkali insoluble polymers (cellulose) from uridine 5'-diphospho-( 14 C)-glucose (UDPG) . .This assay was adapted for the screening of Acetobacter Cel" mutants. After incubation (10 min. at 30°C) , unreacted UDPG in each reaction mixture was separated from the cellulose by heating with NaOH (95°C for 1 hr) and filtering. The radioactively-labeled ( 14 C) cellulose retained on the filter was then quantitated by scintillation counting. The amount of total protein used in the assay depends upon the state of purification of the cellulose synthase. Two or three different sample dilutions were assayed to obtain at least one result in the linear range of the assay (<20% of total UDPG consumed). The 0.2 ml assay mixture contained, as final concentrations, 0.2 mM I 1 C) UDPG (7.5 cpm/pmole), 50 mM Tris, pH 7.5, 10 mM MgCl . 1 mM EDTA, 2 mM CaCl 2 , and the sample to be assayed. Cyclic diguanosine monophosphate (c-di-GMP) was added to 5 uM to some of the assay tubes (c-di-GMP activates the cellulose synthase) . Controls included a tube containing no added sample, and a tube containing the sample, denatured prior to the incubation by adding 4 ml of 0.5 M NaOH. - 33 - The timed reactions were commenced by adding enzyme, vortexing the mixture, and placing the tubes into a 30°C water-bath. Succeeding tubes were started at timed intervals. After 10 min, each reaction was terminated by removing the tube from the water-bath, adding 4 ml of 0.5 M NaOH, and vortexing. When all the reactions were stopped, about 20 g cellulose was added to each tube to act as carrier for the ( 14 C) cellulose. The tubes were then heated in a water bath 95°C for one hour to digest the cells. Using a vacuum manifold, the contents of each assay tube were filtered through a Whatman GF/A filter to isolate the cellulose product (removing any unreacted 14 C UDPG), by passing the reaction mixture through the filter; rinsing the assay tube 3X with deionized water, passing the rinse water; washing the filter 2X with 20 ml deionized water; then with 20 ml 0.5 M HC1; followed by 20 ml deionized water and 20 ml methanol. Cellulose production was quantified by scintillation counting. Each filter was placed in a scintillation vial with 10 ml scintillation fluid (NEN Atomlight, Boston, MA) and quantitative cellulose production determined by ( 14 C) UDPG incorporation into base-insoluble material by scintillation counting. To obtain the specific activity of the ( 14 C) UDPG, an aliquot of the 2 mM ( 1 C) UDPG stock solution was counted. The total possible cpm of the assay was determined from the stock-solution aliquot, and the fraction of total UDPG consumed from each assay tube was calculated as follows: Fraction of total UDPG consumed = ((cpm filter)-(cpm of blank)) (total counts)-(cpm of blank) The nmole of UDPG consumed per minute was calculated as: nmole UDPG/min = (fraction of total UDPG consumed) X (40,000 pmole) X (1/10 min) Activity was expressed on the basis of nmole per minute per ml sample, or nmole per minute per mg protein. Assay for Diquanylate Cyclase Activity The diguanylate cyclase assay was used to identify Acetobacter hosts lacking two or more specific activities, such as a deficiency in cellulose synthase activity and diguanylate cyclase activity. The enzyme diguanylate cyclase catalyzes the production of c-di-GMP, ~ a cellulose synthase activator, from guanosine triphosphate (GTP). The cells were grown, washed, and sonicated as described below for the screening assay. Diguanylate cyclase activity was measured using an assay similar to that reported in Ross, et al., (1987) Nature 325:279. Sonicated cells (1 mg/assay tube) were incubated for 10 min at 30°C in a 0.1 ml reaction mixture containing 0.2 mM [alpha 32 P]GTP, 50 mM Tris HC1, pH 7.5, 10 mM MgCl2, 1 mM EDTA, 5 ml CaCl2, 2 mM phosphocreatine, and 24 units/ml creatine phosphokinase. The reaction was terminated with 10 ml (w/v) 100% trichloroacetic acid. After centrifugation to remove the precipitate, 10 ml of each reaction mixture was spotted on a thin layer chromatography (TLC) plate (Polygram Cel 300 PEI, Macherey-Nagel, Duren, W. Germany, U.S. distributor Sybron/Brinkman, Westbury, NY) . The TLC plate was developed in 1.5 M KH2P0 , pH 3.65, for about 2 hr, autoradiographed, and the areas on the TLC plate - 35 - corresponding to GTP and cyclic-di-GMP were excised and counted in a scintillation counter. Screening Assay To observe restoration of cellulose synthase activity, one needs to isolate a strain which is cellulose synthase negative and diguanylate cyclase positive. The following screening assay is a modification of the cellulose synthase activity assay described above and may be used to determine mutations involving two different enzymes by comparing cellulose synthase activity in the presence or absence of GTP or c-di-GMP. The assay measures cellulose production by suspended, sonicated cells. Mutant Acetobacter strains were classified by assaying sonicated cells under several different conditions. Three classes of Acetobacter mutations were identified. Class I (cellulose synthase negative) strains produced no cellulose under any assay conditions. Class II (diguanylate cyclase negative) strains produced cellulose in the presence of c-di-GMP, but not in the presence of GTP. Class III mutants produced cellulose following activation by either GTP or c-di-GMP. -Mutants in Classes II and III contain cellulose synthase, and show activity in vitro, but produce little or no cellulose in vivo. The deficiency in the Class III mutants has not been defined biochemically. The screening assay was conducted under the following conditions: 1) no nucleotide added; 2) 0.4 mM GTP added; and 3) 5 uM c-di-GMP added. Except for the source of enzyme and the buffer used, the assay procedure and controls were as described above for the cellulose synthase activity assay. - 36 - Six mutant Acetobacter strains were assayed in a single screening. Each time an Acetobacter strain having both cellulose synthase activity and diguanylate cyclase activity was included to monitor consistency between assays. The selected Acetobacter strains were grown for approximately 24 hours at 30°C. The growth medium contained R70-2, 1% Ambrex 1003 (TYE, Universal Foods, Milwaukee, WI), 4% fructose, 0.01% v/v Dow Corning Antifoam B, and 50 mM 3,3-di methylglutaric acid (DMG) , pH 5.0. , 25 ml of medium was inoculated in a 125 ml baffled shake flask with the cells from a frozen seed vial. Before collecting the cells, R70-2 + 0.5% TYE and 1% glucose agar plates were streaked to monitor for contamination. The plates were incubated at 30°C for about 3 days. Prior to collecting the cells, 5 ml of 0.6 M EDTA was added to the medium to prevent clumping. The cells were centrifuged (5000 rpm, 10 min, JA21 rotor) and the supernatant discarded. The pellet was suspended in 20 ml 50 mM potassium phosphate buffer, pH 6.0, and 5 ml 5 M NaCl was added to reduce clumping. Cell density was measured with a Klett meter (10 Klett units ("KU") ■ approximately 40 mg cells/ml). The cells were again centrifuged (5 K rpm, 10 min, JA21 fotor) and the supernatant discarded. The pellets were suspended to 20 mg cells/ml in 50 mM N-(2- hydroxyethyl) piperazine, N'-3- propanesulfonic acid (EPPS, Sigma) buffer, pH 7.5. To sonicate the cells, 0.5 ml of each cell suspension was transferred into a 1.5 ml Eppendorf centrifuge tube. Each tube was sonicated in a cup sonicator (Branson Sonic Power Co., Model 350, Plainview, NY) for 1 min., 80% duty cycle, setting of 7. The assay was performed as described above using 50 ul of sonicated cell suspension for each assay tube, substituting 50 mM EPPS, pH 9.0 for the 50 mM Tris, dropping the 1 mM EDTA, and adding 20 mM MgCl2 in place of 10 mM MgCl2» Each assay condition was duplicated and the duplicates were averaged in the calculations. Several Cel" strains were biochemically characterized. Strain 1306-24 (derived from 1306-3) was found to have normal diguanylate cyclase activity but was defective in cellulose synthase activity. Strains 1306-42 (derived from 1306-21) and C90-1 (derived from 1306-21) were defective in both diguanylate cyclase and cellulose synthase activities. These strains were picked for subsequent studies. Example III Construction of Cosmid Vector and Conjugation Procedure A new cosmid vector, pKT230cos5, was constructed as summarized in Figure 2 for the cloning of a cellulose synthase gene. This vector contains a streptomycin resistance gene (Sm), the cos fragment of phage lambda and cloning sites for insertion of foreign DNA. A 1.85 kb DNA fragment containing the lambda cos site was excised from plasmid pVKlOO (Knauf and Nester, (1982) Plasmid 8:45-55) by digestion with the restriction enzyme Bglll and was cloned in the BamHI site in plasmid pUC19 (New England Biolabs Catalog) . The new plasmid, pUC19cos2, was digested with the restriction enzymes HindiII and X al and the Hindlll-Xmal fragment containing the 1.85 kb cos-containing fragment was cloned into Xmal- and Hindlll-digested plasmid pKT230, thereby inactivating the kanamycin-resistance gene. The resulting vector, 98 - 38 - cosmid pKT230cos5, is not self-transmissible from E. coli to Acetobacter. Therefore, a helper plasmid, pRK2013, is necessary to mobilize the transfer of pKT230cos5 from the donor cells into the recipients cells of Acetobacter strain 1306-24. E. coli strain MM294 transformed with pKT230cos5 was grown at 37°C in R2 medium (20.0 g Tryptone, 10.0 g yeast extract, 10.0 g NaCl, 1.0 L distilled H2O, pH 6.9 plus 2 g/1 glucose (R2-4) and optionally, 15 g/L Bacto agar) containing 100 ug/ml Sm to a Klett reading of 150 KU. E. coli strain HB101 containing the mobilizing plasmid pRK2013 was grown at 37°C in R2-4 medium containing 50 ug/ml Km to a Klett reading of 150 KU. The Acetobacter recipient cells 1306-24 were grown at 30°C in R20-2 medium to a Klett reading of 200 KU. 1 ml of each donor, mobilizing and 2 ml recipient cells were mixed and filtered through a 0.2 micron Gelman disposable filter (Gelman, Ann Arbor, MI), washed twice with 10 ml of R2 medium without antibiotics. The filter was placed on agar plates containing R2-4 medium, The plates were incubated at 30°C for 3 hr to allow mating to take place. After mating between the three strains, the conjugation mixture was resuspended in ' 2 ml of 0.9% sodium chloride. 0.1 ml of this solution was plated on R20-2 medium agar plates containing 50 ug/ml Sm and 20 ug/ml Cm. The plates were incubated at 30°C for 5 days. Acetobacter strain 1306-24 is naturally resistant to 20 ug/ml Cm, while E. coli strains are sensitive to it. Therefore only Acetobacter colonies which had acquired the donor plasmid grew on these selection plates. Subsequent restriction analysis showed that the cosmid pKT230cos5 did not undergo any rearrangements in Acetobacter strain 1306-24. Example IV Construction of an Acetobacter DNA Library Lambda phage will package DNA from 38 to 52 kb in length if cos sites are present at both ends. Since the vector pKT230cos5 was relatively small (13.5 kb), a large amount of Acetobacter DNA (28 to 37 kb) could be inserted and packaged in lambda phage particles. Presuming the genome size of Acetobacter is equivalent to E. coli, only 700 to 1000 clones are presumed necessary to have a complete gene bank. DNA banks were constructed from Acetobacter strain 1306-3 as follows. About 26 mg of nucleic acid were isolated from lawns of Acetobacter 1306-3 on R20-2 agar plates. This nucleic acid was treated with RNase A and RNase Tl to degrade the RNA in the sample. A total of 560 ug of DNA was recovered. This DNA was partially digested with the restriction enzyme Sau3A at four different enzyme concentrations. The DNA was fractionated by size on a 10-40% sucrose gradient. The fraction containing the largest number of DNA molecules between 27-38 kb was selected (approximately 2 ug of DNA). Approximately 1 ug of this DNA was ligated into BamHI-cleaved and dephosphorylated pKT230cos5 DNA, and the ligation mixture was packaged into lambda phage particles. The phage particles were then used to infect E. coli strain K802 recA". Cosmid DNA, isolated from six random E. coli isolates, was used to determine the sizes of the inserted DNA fragments. The six clones had DNA inserts ranging from 8 to 40 kb with an average size of 28 kb. Approximately 2000 clones were picked, individually grown in microtiter dishes, and stored for later screening. The bank was designated pKT230cos5:1306-3A2. - 40 - Example V Identification And Isolation of Cloned DNA That Restored Cellulose Synthase Activity in Cellulose Negative Acetobacter Strains A genetic complementation assay for restoration of cellulose synthase activity was used to isolate cosmid DNA capable of restoring cellulose synthase activity in the Cel" Acetobacter mutants. Screening of Acetobacter Gene Bank Through Conjugations Cosmids from the gene bank pKT230cos5:1306-3A2 (obtained as described in Example IV) were transferred to recipient mutant Acetobacter strain 1306-24 for screening using the mobilizing plasmid pRK2013 in a multiple spot conjugation method described below. Acetobacter strain 1306-24 was grown in R20-2 medium at 30°C with shaking for approximately 28 hr to a Klett reading of 100-150 KU. E. coli HBlOl/pRK2013 was grown in R2-4 medium and 50 ug/ml kanamycin (Km) at 37°C with shaking to a Klett reading of 100 to 150 KU. E. coli K802 recA " (pKT230cos5:1306-3A2) cultures were inoculated from frozen microtiter trays with a flamed frog into microtiter dishes containing 100 ul R2-4 medium plus 50 ug/ml Sm and incubated at 37 β C without shaking for approximately 18 hr. The E. coli HBlOl/pRK20l3 culture was centrifuged down, washed with an equal volume of 0.9% saline to remove the Km, centrifuged down again and concentrated by resuspending in one tenth the original volume of saline. A 10 ul volume of this concentrated E. coli HBlOl/pRK2013 was added to each microtiter well containing 100 ul of 18 hr E. coli K802 recA" pKT230cos5:1306-3-A2 culture. 10 ul volumes of the mixed HB101/pRK2013 and K802 recA" pKT230cos5:1306-3-A2 - 41 - cultures were spotted onto dry 150 mm R2-4 plates using an 8-channel pipette and in an array corresponding to the pattern of microtiter wells so that the donor of each transconjugant could be traced back to its location in the E. coli cosmid bank. Once the spots were dry, an additional 10 ul of each mixed culture was layered over the original spot and allowed to dry. This was repeated until 50 ul of each mixed culture was laid down. The Acetobacter l306-24culture was spun down and resuspended in one tenth the original volume of 0.9% saline. A 10 ul amount of this concentrated culture was layered over each HBlOl/pRK2013 and E. coli K802 recA" pKT230cos5:1306-3A2 spot on the R2-4 plates with the 8-channel pipette. The spots were allowed to dry, then the conjugation mixtures were incubated at 30°C on the R2-4 plate for 3 hr. To determine which transconjugants produced cellulose, each of the mating mixtures was scraped from the mating plates with a sterile toothpick and inoculated directly into 2 ml R70-2 containing 0.5% TYE, 3% glucose, 25 mM DMG, 20 ug/ml Cm and 50 ug/ml Sm in 13 x 100 mm tubes ("test tube selection screen"). The antibiotic Cm inhibits the growth of the E. coli donor * and helper parents. The antibiotic Sm inhibits the growth of the Acetobacter strain 1306-24 which had not received a cosmid. The tubes were incubated at 30°C and checked for formation of pellicles at day 7 and day 14. This procedure allowed visualization of any cellulose that the transconjugants produced. Using the multiple spot conjugation method described above for cosmid transfer and the test tube selection screen for cellulose production, 487 cosmids from the bank pKT230cos5:1306-3A2 were used in matings with the Acetobacter cellulose synthase mutant 1306-24. Of these conjugations 386 showed successful cosmid transfer. Three of these matings mixtures formed a pellicle in the standing test tube screen after 14 days incubation at 30°C. These three cosmid donor cultures were designated T19G9, T20A1, and T20B6. None of the transconjugant colonies arising when these conjugation mixtures were directly plated, showed a Cel + phenotype. It is only when conjugation mixtures were inoculated into standing test tubes that cellulose production could be detected. In later studies it was observed that restoration of Cel + activity was due to recombination and not to true complementation. This might explain the need for a screen using the test tube selection, rather than relying solely on a plating protocol. Confirmation of Restoration of Cellulose Synthase Activity in Filter Matings Cosmids T19G9, T20A1 and T20B6 whose 1306-24 transconjugants produced a pellicle in the test tube selection screen described above were further tested in transfers done by the filter conjugation method with Acetobacter 1306-24 (receipient) , E. coli HB101pRK2013 (helper plasmid strain), and E. coli PKT23OCQS5:1306-3A2 T19G9, -T20A1, and -T2B6 (donor strains) according to the procedure in Example III. 100 ul of the mating mixtures were inoculated for a test tube selection screen. Conjugation frequency for these conjugations was determined by plating serial dilutions of the mating mixtures dirctly after conjugation on R20-2 plates containing 20 ug/ml Cm and 40 ug/ml Sm. As a negative control the vector pKT230cos5 was transferred to 1306-24 in parallel with these conjugations, plated and inoculated into test - 43 - tubes. These 1306-24 pKT230cos5 transconjugants formed no pellicles in the standing test tube screen and served as a control to distinguish between Cel" growth and pellicle formation in standing test tubes. Of the three cosmids previously identified, only cosmid pKT230cos_5 1306-3A2 T19G9 gave positive results, i.e., converted strain 1306-24 from Cel" to Cel + in standing test tube screen. The frequency of conjugation of the cosmid T19G9 was 7.0 X 10~ 8 per recipient cells. Example VI Construction of Cosmids Carrying Truncated And Full-length Cellulose Synthase Gene B Conjugation between the E. coli carrying pKT230cos5T19G9 and Acetobacter 1306-24 was performed on a filter. 100 ul of the conjugation mixture was inoculated for a test tube selection screen as described above. After seven days a pellicle formed in the test tube and was blended in a blender with 25 ml of 0.9% NaCl. The resulting suspension was streaked for single colonies on an R20-2 plate containing 20 ug/ml Cm and 40 ug/ml Sm. A Cel + colony was picked and designated * 1306-24 T19G9#106. The cosmid isolated from 1306-24 T19G9#106 was 16.6 kb in length. When E. coli strains K802 recA" carrying T19G9#106 were used as the cosmid donors in a conjugation with 1306-24 as the recipient, Acetobacter transconjugants showed a Cel + phenotype in 100% of the test tubes in the test selection screen. Therefore, the 16.6 kb cosmids were able to restore cellulose synthase activity in the Cel" mutant of 1306-24. Restriction analysis indicated that the T19G9#106 was a deletion product of T19G9. Nucleotide sequence analysis after the intact gene was cloned confirmed that cosmid T19G9#106 was carrying a truncated cellulose synthase B gene wherein the deletion site was located 142 bp 3' from the unique BamHI site in the coding region of the gene. In a Southern hybridization, a 1.8 kb BamHI-Smal fragment from cosmid T19G9 strongly hybridized with the oligo probe MK172 (its sequence spans from nucleotide 4564 to 4582 in Figure 1). If the molecular weight of the cellulose synthase was not greater than 120 kd, the 1.8 kb BamHI-Smal fragment should contain the 3'-end of the gene. To confirm this hypothesis, a plasmid carrying a full-length cellulose synthase gene was constructed in a three piece ligation as follows. The cosmid vector pKT230cos5 was first digested with BamHI ' and the ends were repaired with the Klenow enzyme in the presence of all four deoxyribonucleotide triphosphates. The DNA was further digested with Hindlll. A 3.5 kb BamHI-Smal fragment from T19G9 containing the 3'-end of the cellulose synthase gene and the Hindlll-BamHI fragment from T19G9#106 carrying the 5'-end of the cellulose synthase gene were ligated into the Hindlll-BamHI repaired vector pKT230cos5 to construct TRT18-1. The construction for TRT18-1 is shown in Figure 3. Example VII In Vitro Cellulose Synthase Activity in Cellulose Positive Transconjugants A 3 kb region of Acetobacter genomic DNA (cosmid T19G9#106) could restore a Cel + phenotype to Acetobacter strain 1306-24 (Example VI). The present example describes the recovery of cellulose synthase activity in the transconjugant Acetobacter strain 1306-24. The assay used was described as the screening assay in Example II. Controls consisted of Acetobacter strain 1306-3 (Cel + ), and strain 1036-24 (Cel~) each carrying the vector pKT230cos5. The Cel + strain 1306-24 T19G9K106 ("the transconjugant") carried a 3 kb fragment of Acetobacter qenomic DNA in the vector pKT230cos5. The cells were grown as described in Example II, with addition of 50 mg/1 Sm, and 20 mg/1 Cm. The cells were collected, separated from cellulose, washed, brought to concentration and sonicated as previously described. In vitro cellulose synthase activity was measured and a BCA (bicinchoninic acid) protein assay developed by Pierce (Chemical Company, Rockford, IL) was used to measure the protein concentration of the sonicated cell preparations. Strains were assayed at a concentration of 2 mg cells/ml. Strains 1306-24 pKT230cos5 and 1306-24 T19G9#106 were also measured at 5 mg cells/ml to check for a possible concentration effect. As shown in Table 1, the cellulose synthase activities of strains 1306-24 pKT230cos5 and the transconjugant 1306-24 were not affected by the cell concentration of the assay. The activity of 1306-3 pKT230cos5 was similar to the activity of strain 1306-21 (not shown) . Thus the vector pKT230cos5 does not appear to affect the cellulose synthase activity. Strain 1306-24, demonstrated a low level of cellulose synthase activity upon activation by c-di-GMP. This was true for most Class I (cellulose synthase negative) Acetobacter mutants. Although the mutation in cellulose synthase activity appears somewhat leaky in vitro, the cells appear to make very little cellulose in vivo (in shake flasks). The 3 kb insert increased the cellulose synthase activity of strain 1306-24 roughly ten-fold (0.4 to 4.1 nmole/min mg) at 5 mg cells/ml in the assay tube. This correlated with the appearance of the cellulose positive phenotype. The transconjugant strain 1306-24 had the same - 46 - c-di-GMP-stimulated activity as did the cellulose positive strain 1306-3. Results for TRT18-1, determined in a separate experiment using appropriate controls, confirmed that this plasmid was able to convert a Cel" phenotype to Cel + , and secondly, that, in the in vitro assay, the activity of the enzyme was comparable to that observed for the pKT230cos5 vectors carrying the 3 kb T19G98106 Acetobacter DNA insert shown in Table 1. Table 1 Conversion of Strain 1306-24 from Cel" to Cel + : Recovery of In Vitro Cellulose Synthase Activity Cell Concentration Cellulose Synthase Activity in assay (nmole UDPG consumed) Strain (min-mg) (by Klett units mg/ml) No c-di-GMP + c-di-GMP 1306-3pKT230cos5 2 0 4.1 1306-24pKT230cos5 2 0.2 0.6 1306-24+insert 1 2 0.2 3.9 1306-24pKT230cos5 5 0.1 0.4 1306-24+insert- L 5 0.1 4.1 pKT230cos5 with the 3 kb T19G9#106 Acetobacter ' DNA insert. Example VIII The Nucleotide Sequence of The Cellulose Synthase B Gene In this example, the restriction map of the cloned celluMose synthase B gene of the invention was used to guide the subcloning strategy for the determination of the nucleotide sequence of the cellulose synthase gene carried on cosmid T19G9#106. The cloned insert DNA carrying the cellulose synthase gene in cosmid T19G9#106 was physically mapped using restriction enzymes. This map information was then used for subcloning the Acetobacter DNA insert into M13 RF DNA for sequencing analysis as described by Messing in Methods in Enzymol. 101:20-78 (1983). The nucleotide sequence of the restriction fragments was determined by the chain termination methods described in Innis, et al., (1988) Proc. Natl. Acad. Sci. USA 85:9436-9440, using Tag DNA polymerase (Cetus Corp. Emeryville, CA) . Example IX Cellulose Synthase Gene Disruptions And Restoration of Cellulose Synthase Activity in The Mutant Acetobacter Strain 1306-24 To determine whether cellulose synthase was expressed from the plasmid TRT18-1, three different frameshift mutations were introduced in the coding region of the cellulose synthase gene. The mutated genes were introduced into plasmid TRT18-1 which was then individually transferred into Acetobacter strain 1306-24. Three mutations were introduced in the coding region of cellulose synthase as follows: a Bglll linker sequence was introduced at the EcoRV site at nucleotide position 3113 and at the StuI site at nucleotide position 3954. The EcoRV insertion should create a termination codon TGA, as well as a frameshift mutation. The Bglll linker that was introduced at a StuI site at position 4564 should create a frameshift mutation. The third mutation was introduced at the BamHI site at nucleotide position 1899 and was created by filling-in the BamHI site with Klenow. - 48 - The DNA of these plasmids was analyzed by restriction digest and verified by DNA sequencing. Each mutated gene was conjugated into the Class I mutant strain 1306-24. Single colonies from plates were picked into standing test tubes and the results of these conjugations are presented in Table 2. The ability to form a pellicle was scored in tubes directly inoculated with the conjugation mixture or with colonies from selection plates. All mutated genes were able to convert the Cel" mutation present in 1306-24 which suggests that conversion of the mutation occurred via recombination between the plasmid and the chromosome. The results suggest that the chromosomal and the plasmid synthase genes recombined to form a functional copy of the gene. Presumably, transcriptional and translational signals are provided by the chromosomal copy. Qualitatively speaking, the size of the pellicles formed in all tubes were similar, suggesting that level of expression in all transconjugates was the same. Table 2 Conjugation of Mutated Cellulose Synthase DNA Host 1306-24 (Class I Mutant) Standing Standing Conju- Mutation Conjugation Tube 1 Tube 2 gation# Plasmid Site Frequency (conj. mix) (colonies) CRT18 TRT 18-1 None 2 X 10" 7 Cel + (6/6) Cel + (10/10) CRT19 TRT 28-1 BamHI 4 x 10" 7 Cel+(6/6) Cel + (10/10) CRT20 TRT 29-1 StuI 3.5 X 10" 7 Cel + (6/6) Cel + (ιo/ιo) CRT21 TRT 30-1 EcoRV 2 x 10" 7 Cel+(6/6) Cel + (10/10) Example X Cloning of a 3.5 kb Endogenous Plasmid From Acetobacter Strain Acetobacter CMCC824, a proprietary strain of Cetus Corporation, a cellulose producing strain isolated from a vinegar culture (CMCC824) contains a 3.5 kb plasmid. To isolate this plasmid, a single colony from an R20-2 plate was inoculated into 50 ml of R20-2 and grown without shaking at 30°C for 48 hours. The pellicle was washed twice in 100 ml of 50 mM Tris, 10 mM EDTA, pH 8.0, homogenized in a Beckman blender and filtered through cheesecloth. The cells were pelleted and plasmid DNA was prepared following a modified SDS lysis procedure by Guerry, et al., (1973) J. Bacteriol. 116:1064. To the cell pellet was added 1.5 ml 25% sucrose, 0.05 M Tris-HCl, pH 8 and the cells were gently resuspended using a Pasteur pipette and then transferred to a 12 ml polypropylene tube. After 0.15 ml lysozyme (10 mg/ml in 250 mM Tris-HCl, pH 8) were added, 0.6 ml 0.25 M Na2~EDTA, pH 8 was added and the tube inverted before placing on ice for 20 min. Next, 0.6.ml of 10% SDS were added to the tube, which was inverted slowly at room temperature until clearing was observed. About 0.9 ml of 5M NaCl were added and the tube inverted until the formation of a white precipitate was observed. The tube was placed on ice at 4°C for 2-20 hr and then the precipitate was spun down at 20,000 x g for 45 min at 0-4 β C. The supernatant was decanted and an equal volume of distilled water was added. An equal volume of twice-distilled, Tris-equilibrated phenol (pH 8.0) was added and the tube gently inverted for 3-4 min before centrifugation at 20 β C, 5000 x g for 15 min. The - 50 - aqueous layer was carefully removed using a Pasteur pipette and placed in a polypropylene tube capable of holding 2-3X of the present volume. Next, 1/10 volume of 3M NaOAC and 2-3X volumes of absolute EtOH were added and mixed well before the tubes were placed at -20°C overnight. The supernatant was collected by centrifugation (20,000 x g for 30 min at 0°C) and the pellet washed with 5-10 ml cold 70% EtOH, and then recentrifuged at 20,000 x g for 10 min to recover the pellet. The pellet was dissolved in 50-100 ul TE (100 mM Tris, 1 mM EDTA). The plasmid DNA was purified by ethidium bromide-CsCl density centrifugation. To physically map this plasmid, the CsCl prepared DNA was digested with the following restriction enzymes: Hindlll, EcoRI, PstI, BamHI, Sad, PvuII. Of the enzymes tested, only Sacl was able to linearize this plasmid. S_acI-digested plasmid was ligated to Sacl-digested plasmid pUClδ (New England Biolabs) for cloning in E. coli. This shuttle vector was designated pUC18-824. In order to physically map pUC18-824, the plasmid was digested with a variety of restriction endonucleases. , A restriction map of pUC18-824 is shown in Figure 4. Example XI Electrotransformation To demonstrate that the shuttle vector pUCl8-824 can be transferred to Acetobacter strains, pUCl8-824 plasmid. DNA was prepared from an E. coli host strain DG98, carrying pUC18-824 according to Clewell, et al., (1972) J. Bacteriol. 110:667. Acetobactor strains 1306-21 and 1306-24 were washed as described in Dower, et al., (1988) supra. An electroporation device - 51 - designed for bacterial culture transformation was used for Acetobacter electroporation. While the device used in this example was a modification of a mammalian-designed electroporation device, a commercial device, such as the Bio-Rad Gene-Pulser Apparatus (120v, 50/60 Hz) may be substituted to obtain equivalent transformation frequencies. The electroporation parameters were optimized with plasmid pKT230cos5T19G9ftl06 as follows: A field force of 9.0 Kilovolts (KV) and 9.5 KV was desirable for strains 1306-21 and 1306-24, respectively. A pulse duration (RC value) of 25 microfarads/750 ohms X=18.75 msec) was determined to be optimal. Upon incubation at 30"C for an additional 5 days, greater than 10 4 transformants per microgram of DNA were obtained on R20-2 plates containing 100 microgram/ml ampicillin. pUC18-824 plasmid DNA was isolated from four Acetobacter candidates and transformed into E. coli and Acetobacter. The shuttle vector is stable after growth in Acetobacter since restriction analysis (of four total clones) showed the presence of all the polylinker sites and the absence of discernible deletions. Example XII Construction of pUC18-824 Containing The Cellulose Synthase B Gene The cellulose synthase B gene can be isolated from plasmid TRT18-1, the construction of which is taught at Example VI, or alternatively, since the nucleotide sequence of this gene is provided herein, the full-length gene may be directly synthesized by chemical means or may be obtained from the constructed gene bank using a primer. For example, the primer oligonucleotide MK170 (TGCCCTGGCCAGATGTCAGCA) was used to probe the 1760 individual cultures from the constructed gene bank, and six clones were isolated for further characterization. Three cosmids isolated from three of these clones were designated as T5A1, TIC2 and T5D2. Restriction and Southern analysis of the above isolated cosmids indicated that they all carried more than 8 kb of DNA sequence 5' of the cellulose synthase B gene, as well as the entire coding sequence for the cellulose synthase B protein product. Southern analysis of the cosmid DNAs, with the primer MK170 as the probe, suggested that a 7.2 kb BamHI fragment from T5A1 carries most of the cellulose synthase B gene, as well as additional sequence immediately 5' of the gene. Therefore, the 7.2 kb BamHI fragment was subcloned in plasmids pUClδ and pBR322 for nucleotide sequence analysis. A restriction map of the 7.2 kb BamHI fragment is shown in Figure 5. An approximately 8.3 kb Smal fragment shown in this figure contains the intact, full-length cellulose synthase B gene. This gene was isolated from plasmid T5A1 for use in the construction with the cloning vector pUC18-824 as described below. Southern analysis also indicated that the organization of the cellulose synthase B gene locus in the chromosome is identical to that of the cosmid T5A1; therefore, the Acetobacter sequence in the cosmids has not been extensively rearranged. The 8.3 kb Smal fragment carrying the cellulose synthase B gene and about 3 kb upstream sequence (see the restriction map in Figure 5) was cloned into the Smal site' of pUC18-824. The resultant plasmids carrying the opposite orientations of the 8.3 kb Smal restriction fragment, were designated as pUC18-824 FS-1 and pUC18-r824 FS-6, respectively. A restriction map of FS-6 is provided in Figure 6. When such plasmids were transformed into 1306-24 (a cellulose synthase deficient strain), 1306-42 and C90-1 (both deficient in diguanylate cyclase and cellulose synthase activities), the transformants showed the Cel + colony phenotype on plates. Therefore, in contrast to the "recombination events" observed in the earlier experiments, it was concluded that the protein encoded by the 8.3 kb Acetobacter DNA insert is directly capable of complementing the cellulose synthase mutations carried in the mutants. In vitro assays confirm the ability of the plasmids pUC18-824 FS-1 and pUC18-824 FS-6 to restore cellulose synthase activity to the cellulose synthase negative mutant strain 1306-24. The in vitro cellulose synthase assay of the transformants and control strains was carried out as described in Example VII. As shown in Table 3, the transformants, 1306-24 pUC18-825 FS-1 and 1306-24 pUC18-824 FS-6 showed cellulose synthase specific activities higher than that of the original Cel + parent strain, 1306-3 (1.3X and 1.8X, respectively) . Table 3 Conversion of Strain 1306-24 from Cel" to Cel + : Recovery of In Vitro Cellulose Synthase Activity Cellulose Synthase Activity Strain nmole UDPG incorporated/(min-mq protein) no c-di-GMP + c-di-GMP 1306-3 0.04 2.05 1306-24 0.06 0.07 1306-24 pUC18-824 0.06 0.10 1306-24 pUC18-824 FS-1 0.10 2.59 1306-24 pUC18-824 FS-6 0.10 3.71 Example XIII Construction of an Expression Vector in Acetobacter Plasmid pUCl9 (New England Biolabs) was digested with the restriction enzyme Sad. The linearized plasmid was ligated with Sacl-restricted Acetobacter plasmid 824. The resultant plasmid was designated pUC19-824. The cellulose synthase gene from the 8.3 kb Smal fragment was cloned as a Hindlll-Smal fragment (i.e., 4.9 kb) into the Hindi!I-Smal sites in the linker region of the pUC19 plasmid (see Figure 8) so that its transcriptional direction was identical to the lac promoter. This construction placed the gene under the control of the lac promoter in Acetobacter. Since the lac promoter is a constitutive promoter, expression of cellulose synthase in the absence of the lad gene product would be unregulated in Acetobacter. The plasmid was designated pALl. Plasmid pALl was used to transform Acetobacter strain 1306-24 and was shown to complement the cellulose synthase-deficient phenotype, resulting in a Cel + phenotype on plates. Example XIV Identification of The Cellulose Synthase Operon A. Identification of the First Gene in the Operon The 7.2 kb BamHI restriction fragment, shown in Figure 5, from the Acetobacter chromosome was identified as carrying an additional 4.6 kb nucleotide sequence upstream of the cellulose synthase B gene. To investigate whether this region contains a gene involved in the biosynthesis of cellulose, the nucleotide sequence upstream of the cellulose synthase B gene was determined as follows. The 7.2 kb BamHI restriction fragment was cloned into the BamHI site of pBR322. A 2.3 kb SacII fragment, a 0.9 kb Bglll fragment and a 3.2 kb BamHI-Bqlll fragment of the 7.2 kb BamHI fragment from the pBR322 recombinant plasmid were subcloned into the SacII or BamHI sites of the Bluescript (Stratagene) KS vector, respectively. These three subclones and the pBR322 recombinant plasmid, carrying the entire BamHI fragment, were then purified by CsCl density gradient and used as templates in the dideoxy chain termination method for nucleotide sequence analysis. The dideoxy chain termination methods were performed as previously described except that Sequenase was used to substitute for the Klenow fragment in the extension reaction. The nucleotide sequence of the cellulose synthase operon is shown in Figure 1. Assuming that the ATG codon at nucleotide 2594 is the initiation codon for the cellulose synthase B gene, the nucleotide sequence of the coding region of the cellulose synthase B gene spans from nucleotide 2594 to 4999. Since the mature protein starts with the alanine codon at nucleotide 2666 (see Example XIV), the cellulose synthase appears to have a 24 amino acid leader sequence. The deduced amino acid sequence of this leader peptide is functionally similar to leader peptides carried by secreted and membrane proteins from a variety of bacteria. Therefore, the cellulose synthase protein encoded by the cellulose synthase B gene may be a membrane protein. - 56 - B. Localization of the Transcriptional Initiation Site 1. RNA isolation: Acetobacter 1306-21 was grown in R70-2 medium containing 20 ug/ml Cm and 0.1% (v/v) cellulase (Genencor) at 30°C with shaking to late log phase (O.D.600 nm - 0.7). The cells were then harvested by centrifugation at 6000 rpm for 10 min at 4°C and resuspended into 2.5 ml of NaOAc, pH 6.0 buffer containing 1 mM EDTA and 1% SDS. An equal volume of phenol/chloroform solution were added to the cell suspension and the mixture was sonicated for 15 sec. After 10 min incubation at 60°C, the mixture was centrifuged and the aqueous layer was then extracted twice more with phenol/chloroform. After the extractions, the RNA was precipitated with isopropanol and NaOAc at -70°C overnight. The RNA was harvested by centrifugation, washed with 100% ethanol and dried before it was resuspended into 120 ul of DEPC-treated distilled water. To degrade the DNA in the RNA solution, DNasel (Sigma) was added to 10 ug/ml and the mixture was incubated at room temperature for 20 min. The digested mixture was extracted twice with an equal volume phenol/chloroform. Then the NaOAc concentration of the aqueous layer was adjusted to 0.3M and the RNA was precipitated with an equal volume of isopropanol. The purified RNA was washed with 80% ethanol, dried and resuspended into 40 ul of DEPC-treated distilled water. 2. Primer extension: The oligodeoxy- ribonucleotide GE13 (5'-TGCGGCGATAAGTGCACA-3' ) was labeled with gamma- 32 P ATP and T4 polynucleotide kinase. The unincorporated nucleotide was removed by ethanol precipitation. The labeled oligodeoxyribonuc- leotide was resuspended into 100 ul of 0.3M NaOAc solution. The specific activity of the primer was approximately 4 x 10 6 cpm/pmole. Labeled primer (0.02 and 0.2 pmoles) was used for primer extension analysis. The labeled primer was mixed with 50 ug RNA. The mixed nucleic acids were coprecipitated with ethanol and then resuspended in 30 ul of hybrization buffer containing 50 mM HEPES, pH 7.5, 1 mM EDTA and 300 mM NaCl. The hybrization reaction was carried out at 30°C for 10 min. After hybridization, the mixture was treated with AMV reverse transcriptase. The reaction was carried out at 42°C for 90 min, then terminated by adding 1 ul of 0.5 M EDTA and 1 ul of RNase (1 mg/ml) . After 30 min incubation at 37°C, the mixture was extracted with phenol/chloroform. The cDNA was precipitated, dried and resuspended in 3 ul 10 mM Tris-HCl, pH 8.0, containing 1 mM EDTA. 4 ul of formamide was added to the cDNA suspension and the mixture was boiled for 3 min before it was loaded on a DNA sequencing gel. The primer extension analysis indicated that the transcriptional. initiation site was located within the region 5' of the first gene in the cellulose synthase operon. The transcriptional initiation site of the operon is marked by a downward arrow positioned over nucleotide 235 in Figure 1. C. Cloning of Genes C and D The construction of pABCD is outlined in Figure 8. In the construction of this plasmid, a 1.8 kb BamHI fragment of pFS-6 was replaced with a 5.5 kb BamHI fragment from TRT11-4. The 1.8 kb BamHI fragment of pFS-6 carried the 3' 426 bp of the - 58 - cellulose synthase B gene and approximately 1.4 kb of the C gene. The substituted 5.5 kb fragment contained the entire C gene and an additional 3' sequence. The 5.5 kb fragment carried on TRT11-4 was originally isolated from T19G9 and cloned as a 5.5 kb BamHI fragment into the BamHI site of pUC18 to construct TRT11-4. Fifteen micrograms of TRT11-4 DNA was digested to completion with the restriction endonuclease BamHI at 37°C for one hr. The digested DNA was run on a 0.8% GTG agarose gel. The 5.5 kb BamHI fragment was cut from the gel, electroeluted and precipitated with ethanol and resuspended in a small volume of H2O. Eleven micrograms of pFS-6 were digested to completion with BamHI at 37°C for 1 hr, releasing 1.8 kb of DNA from the 12.6 kb vector fragment containing the 5' portion of the cellulose synthase operon. The digest was run on a 0.8% agarose gel and the 12.6 kb fragment containing the pUC18:824 vector sequence, the cellulose synthase promoter, the A gene, and the 5' portion of the B gene was cut from the gel and electroeluted. The purified DNA was treated with calf alkaline • phosphatase and then ligated to the 5.5 kb BamHI fragment isolated from TRT11-4. The ligation was carried out under standard conditions with a 10:1 molar ratio of 5.5 kb insert to 12.6 kb vector DNA. The ligation mixture was used to transform E. coli DGlOl competent cells. The transformation mixture was plated on R2-4 plates with 50 ug/ml ampicillin and incubated at 37°C overnight. Thirty-six ampicillin resistant transformants were picked from these plates and cultured in R2 media containing 50 ug/ml ampicillin at 37 β C with shaking for approximately 6 hr. Alkaline lysis miniscreen DNA was - 59 - isolated from 36 of these transformants. The DNA was analyzed by restriction digestion with the endonucleases BamHI and Smal. Six of the isolates showed insertion of the 5.5 kb fragment, only two of the six showed the 5.5 kb fragment in the correct orientation to restore the B gene open-reading frame. These isolates, designated pABCD #1 and #32, showed a restriction pattern corresponding to the plasmid map in Figure 8. Cultures containing the plasmids were used to prepare and isolate purified plasmid DNA. Ten ug of pABCD #1 DNA was used to transform -40 ul of 1306-3 cells under standard electroporation conditions. One ml of R20-2 media was added to the transformation mixture and the cells were plated on R20-2 plates containing 100 ug/ml of ampicillin. After 7 days incubation at 30°C, 547 ampici11in-resistant colonies were visible on the plates. Three hundred seventy-six colonies (approximately 69%) showed a very pointed Cel + colony phenotype, 171 (31%) colonies showed a flatter, more warty, but still Cel + phenotype. Four colonies of each type were streaked on R20-2 with ampicillin at 100 ug/ml and incubated at 30°C for 4 days. After 4 days the colony types on all 8 plates were indistinguishable. One colony from the streak of a small pointed colony was picked into 25 ml R70-2 with 0.5% TYE, 3% glucose, 25 mM DMG, 0.1% cellulose, and 50 ug/ml ampicillin and incubated at 30°C with shaking for 24 hr. After 24 hr, glycerol was added to the culture to 15% of total volume and 1.5 ml aliquots were frozen for storage at -70 β C. This stock was designated 1306-3 pABCD. - 60 - D. Sequence and Structure of the Cellulose Synthase Operon The chain termination method was used to sequence the cellulose synthase operon. Double-stranded DNA carrying the operon was used as the DNA template. The nucleotide sequence of the region from pABCD is shown in Figure 1. The cellulose synthase operon is 9217 bp in length and consists of four genes. Genes A, B, C and D are 2,262 bp, 2,406 bp, 3,957 bp and 468 bp in length, respectively. The molecular weights determined by and suggested roles of the gene products are as follows: Amino Gene Acid Molecular Associated Product Residues Weight Function 754 84 kd Cellulose synthesis in vivo; diguanylate cyclase and cell¬ ulose synthase in vitro activities B 802 85 kd Cellulose synthesis in vivo; cellulose synthase in vitro activity 1319 141 kd Cellulose synthesis in vivo 156 17 kd Cellulose synthesis in vivo Computer analysis of the DNA sequences at the 3' end of the D gene revealed a region with the potential of forming a stable stem-and-loop structure. As shown in Figure 1 by the underlined section, this region is positioned 26 bp 3' of the termination codon of the D gene and corresponds to a transcription terminator region of the operon. - 61 - Example XV Cell Growth, Cellulose Production and Cellulose Synthase Activity in Recombinant Strains A. Studies With 1306-21 pUC18-824 pABCD In this study, overexpression of cellulose synthase activity in 1306-21 pABCD was tested in shake flask experiments. The construction of 1306-21 pABCD was similar to the construction of 1306-3 pABCD (See Example XIV). Culture medium for all stages of the experiment was R70-2 with 10 uM FeCl3, 1% TYE, 25 mM DMG, and 4% glucose (1306-21) or 4% fructose (1306-3). The seed medium contained 0.1% cellulase. Ampicillin was added at 50 ug/ml to medium used for growing plasmid containing cultures. Medium was dispensed into 125 ml baffled flasks, with 25 ml per flask. Strains 1306-21, 1306-21 pUC18-824 (the host strain plus the shuttle vector), 1306-21 pUC18-824 pABCD (normal—the phenotype like parent), and 1306-21 pUC18-824 pABCD (spired—its growth on plates was raised and more tapered than the parent) were individually tested. Each culture was adjusted to 0.72 g/L (turbidity 1.8 ODgβo) using sterile saline. Tes flasks were inoculated with 0.2 ml of seed culture (2% v/v inoculum). Six flasks of each strain were inoculated and incubated at 30°C, 125 rpm, 2-inch throw. Flasks were harvested after one, two, and five days. Duplicate flasks were harvested at each time point for cell mass and cellulose measurements. In addition, cultures from the five day flasks were checked for plasmid retention, by observing antibiotic resistance on plates (patch test) . Thirty colonies were tested for each strain. To measure cellulose production and cell concentration, the flask contents of each sample were transferred to a 100 ml beaker. The suspension was then macerated for one minute with a large Tekmar probe at 50% full power. After that the suspension was centrifuged at 5,000 rpm for 10 minutes. The supernatant was discarded and the pellet was resuspended in 15 ml saline solution and incubated for 15 minutes with occasional stirring. The sample was again centrifuged and the above wash step repeated. The pellet from the second wash step was resuspended in 15 ml of 0.1 N of NaOH and incubated at 60°C with mild agitation for 60 minutes. The suspension was centrifuged and the NaOH supernatant was used to analyze cell concentration while the pellet was used to analyze cellulose concentration. The pellet was resuspended in 15 ml deionized water and left at room temperature for 15 minutes with occasional stirring. Then the sample was centrifuged and the above wash procedure was repeated for a total of three times. After the last centrifugation step, the cellulose precipitate was dried at 60°C overnight in a vacuum over and then weighed. The supernatant was neutralized with HC1 (approximately 0.05 ml HC1 to 0.5 ml sample) and the protein concentration was assayed by the Lowry method. Cell concentration ■** - * protein concentration x 1.54. Cell growth and cellulose production are summarized in Table 4. Table 4 Cell Growth and Cellulose Produc ion Cellulose Cells g/L Cellulose/ g/L Cells 1306-21 x s day 1 X S 1.78 x +0.006 day 2 0.51 +0.03 4.58 +0.32 3.52 day 5 1.16 +0.02 6.99 +0.16 3.95 2.92 +0.15 2.40 1306-21 PUC18-824 day 1 0.91 +0.01 day 2 0.14 +0.06 3.59 +0.21 6.54 day 5 0.92 +0.08 6.89 +0.01 3.91 3.07 +0.06 2.24 1306-21 pABCD (spired) day 1 1.16 +0.12 day 2 0.14 +0.04 -78 +0.05 8.42 day 5 0.72 +0.04 7.59 +0.07 6.65 2.59 +0.04 2.93 1306-21 pABCD (normal) day l 1.06 +0.06 day 2 0.14 +0.01 4.40 +0.28 7.41 day 5 0.76 +0.05 7.28 +0.10 5.82 2.81 +0.01 2.59 1306-3 day 1 1.87 +.17 day 2 1 .38 + .11 2.67 +.21 1.36+, ,01 day 5 2. .11 + .11 3.02 +.01 1.27+. 04 2, 82 + .19 0.96+. 09 1306-3 DUC18-824 day 1 1.56 +.01 day 2 2.39 1.26 +.11 1.24+.10 +.04 day 5 3.88 2.25 +.42 1.08+.18 +.01 3.70 +.17 1.05+.05 1306-3 pABCD day l 2, 92 +.11 day 2 3, 90 1.20 +.04 2.44+.18 +.01 day 5 3.66 2.45 +.03 1.59+.01 +.13 2.97 +.07 1.24+.08 Cellulose to cell ratio is an indicator for cellulose specific productivity. In the first two days of growth the cellulose to cell ratio in pABCD 1306-21 strains is significantly higher than those of the control 1306-21 strains. The pABCD (spired strain) seems to produce more cellulose than the pABCD (normal) strains. Both recombinant strains produce more cellulose than the control strains at the end of growth. In the strains with the ampicillin marker, the plasmid stability of the day 5 culture was shown .to be 100%. The retention of the marker does not measure the degree of rearrangement that may occur with the cellulose synthase genes on the plasmid. It is possible that the strains at day 5 are not producing cellulose at the same rate that they did at day l and 2. Evidence supporting this hypothesis is seen in the colony phenotypes from day 5 plating. The spired strain of pABCD failed to show the unusual colony morphology on those plates. Cellulose production with 1306-3 pUC18-824 pABCD was higher than the 1306-3 and 1306-3 pUC19-824 control strains. This .was correlated with an increase in the in vito activity of cellulose synthase (see below). Cell growth with the two strains was similar. Consequently the cellulose to cell ratio with 1306-3 pUC18-824 pABCD was also significantly higher than that of 1306-3 alone. Table 5 Cellulose Synthase Activity Strain nmoles/(min*mg protein) Day 1 Day 2 Day 5 1306-3 2.3 0.7 0.3 1306-3 pUC18-824 1.2 0.6 0.3 1306-3 pUC18-824 PABCD 3.5 2.3 0.3 - 65 - The recombinant strain 1306-21 pABCD was also tested in a Chemap fermentor for cell growth and cellulose production. Contrary to that observed in the flasks, the performance of this strain was similar to that of the parent strain. It is believed that instability of the recombinant strain may be responsible for the absence of enhanced cellulose production. Overexpression of the chromosomal cellulose synthase operon genes would eliminate the instability of the recombinant strain. B. Studies with PUC18-824 FS6 (AB) Fifteen isolates of 1306-3 (Cel + ) carrying pUC18-824 FS6 (which carries the cellulose synthase promoter and genes A and B) were used to screen for overexpression of cellulose synthase activity. The cells were collected, washed, suspended and broken, and the standard in vitro cellulose synthase assay was carried out as described in Example II. All of the fifteen isolates demonstrated in vitro cellulose synthase activity significantly in excess of that of the control strain (1306-3 pUC18:824). The activities range from 1.5 to 2.4x higher than the control strain. Two of the fifteen strains screened (#302 and #303) were examined at exponential and stationary phases. The conditions were similar to that described in Example XV except that glucose was replaced with fructose. As shown in Table 5, at day 2 the activities of the control strains 1306-3 and 1306-3 pUC18-824 retained 30% and 40% of the day 1 activity, with declining activity over time. At day 2 isolates #302 and #303 showed a decline to 45% and 50% of the day 1 activity, also with declining activity over time. However, these latter strains both showed about 2x higher activity than did 1306-3 at day 1, while the activities were about 3x higher at day 2. Table 5 Cellulose Synthase Activity Strain nmoles/(min*mg protein) Day 1 Day 2 Day 5 1306-3 5.5 1.7 0.5 1306-3 pUC18-824 5.9 2.4 0.3 1306-3 pUClδ-824 FS6 302 12.5 5.6 0.9 1306-3 pUC18-824 FS6 303 11.0 5.4 1.3 Cellulose production in these recombinant strains was similar to that observed for the parent strains. It was also observed that cellulose synthase activity was suppressed in strains carrying a disrupted cellulose synthase B gene. This gene was disrupted through the insertion of a 1.1 kb BamHI fragment encoding the streptomycin resistance gene at the internal BamHI site of the cellulose synthase B gene. * The insertion of the streptomycin resistance gene interrupted the cellulose synthase B gene near its 5' end. Example XVI Chromosomal Promoter Replacement Acetobactor appears to have a very efficient recombination system which may cause instability - problems with any plasmid carrying a large segment of autonomous DNA. To overcome this potential problem, the operon can be overexpressed at the chromosomal level using heterologous control elements to drive transcription of the chromosomal cellulose synthase operon. The construction of plasmids pTac25-l, pLac21-7 containing heterologous promoters and the - 67 - intermediate vectors used for their construction is described as follows and presented schematically in Figure 9. A. Construction of MPll:Pcs:LF01 Fifteen micrograms of pFS-l DNA were digested with HindllI, releasing a 2.5 kb fragment carrying the cellulose synthase operon promoter. The digest was run on a 0.8% GTG agarose gel, the 2.5 kb fragment carrying the promoter was cut from the gel, electroeluted and ligated to double-stranded M13 MP phage DNA, which had previously been digested with Hindlll. The ligation mixture was used to transform E. coli strain DG98. The transformed cells were plated on R17-3 plates with lawns of E. coli JM103 and incubated at 37°C overnight. Eleven of the resulting phage plagues were picked and inoculated in 3 ml of log phase JM103 diluted 1:100 with R2-6 medium (5.0 g Tryptone, 5.0 g yeast extract, 5.0 g NaCl and 1.0 L distilled H2O, pH 6.9). These cultures were incubated at 37 β C for six hr and spun down in Eppendorf tubes. The supernatant containing free phage was stored at 4°C while mini-screen DNA was prepared from the cell pellets by the alkaline lysis method. The mini-screen DNA was analyzed by restriction digestion with the enzymes Hindi11 and Bglll. One clone was chosen and was designated MPll:Pcs. The supernatant from this clone was used to infect JM103. A 15 ml culture of the JM103 MPll:Pcs was grown for six hr, spun down, and single-stranded phage DNA was isolated from the supernatant. The phage DNA MPll:Pcs was mutagenized with oligonucleotide LFOl (5'-GAATATATAACGGAGCTCCCGGGATCC ACCTGTTTTACC-3'), which contains the restriction site - 68 - sequences for the enzymes SstI, Smal, and BamHI flanked by 12 bp of cellulose synthase operon promoter sequence on each side. One picomole of the single-stranded phage DNA MPll:Pcs was incubated with 10 pmoles of LFOl at 68°C for 5 min and then allowed to anneal with the promoter sequences for 30 min at 37°C. The annealed molecules were then extended to form complete double-stranded DNAs by adding dNTPs to 0.5 mM and the Klenow fragment of DNA polymerase 1 to 0.25 units/ul. The extension proceeded at 4°C for 30 min, and then at 37°C for one hr; it was then heated to 68°C for 10 min and the mixture used to transform ' JM103 competent cells. The transformation mixture was plated with JM103 lawn cells on R2-4 plates with 3 ml R-17 (10.0 g N-Z amine, type A, 5.0 g NaCl, 0.04 g X-gal in 2.0 ml DMF), 10 mM MgCl2, 0.7% top agarose. Phage plaques were lifted from these plates onto nitrocellulose filters and the plates stored at 4°C. The filters were baked at 80°C for two hr and hybridized with the 32 _ι a ]- , e ι e( 3 oligonucleotide probe LF02. LF02 contains a subset of the sequence of the oligonucleotide LFOl used for mutagenesis, the three restriction site sequences with only 2 bp of cellulose synthase promoter sequence on either side. The sequence of LF02 is 5'-GGGAGCTCCCGGGATCCAC-3' . Hybridization was carried out at 58 β C. The filters were washed at 58°C with sequential 5 min washes of 5x SSC, 2x SSC, and 2x SSC containing 0.1% SDS. Kodak X-OMAT AR film was exposed to the filters for 60 hr. After 60 hr, dark spots appeared on the developed film which corresponded to the lifted plaques still present on the plates. Sixteen plaques which corresponded to dark spots on the film were isolated and the RF DNAs were analyzed by restriction digestion with the enzymes Hindlll, BamHI, and Sstl. MPll:Pcs:LF01 corresponded to the map provided in Figure 9. The introduced restriction sites in MP11:Pcs:LFOl are for substitution of heterologous promoters. The flanking regions serve as the sites for homologous recombination between the plasmid and the Acetobacter chromosome in gene replacement. The phage supernatant from culture MP11:Pcs:LFOl was plaque purified, checked again for the appropriate restriction pattern, then used for infection and preparation of double-stranded cesium chloride gradient purified DNA. B. Construction of pACYC184:Pcs Twenty micrograms of MP11:Pcs:LFOl DNA were digested with 200 units of Hindlll, and the 2.5 kb fragment containing the cellulose synthase promoter region was gel purified, electroeluted into O.lx TEA in a dialysis bag at 100 volts for 2 hr. The DNA and buffer were removed from the bag, extracted with phenol/chloroform, precipitated with sodium acetate in ethanol and resuspended in Tris-EDTA buffer. This fragment was ligated to HindiII-digested pACY184 (New England Biolabs) with an insert-to-vector ratio of 10:1 at an ATP concentration of 2 mM at 16°C overnight. The ligation mixture was transformed into MM294 competent cells and plated on R2-4 plates containing Cm at 20 ug/ml. The plates were incubated at 37°C overnight and over 15,000 Cm R colonies appeared. To test for inactivation of the tetracycline resistance gene of pACYC184 by the insertion of the Pcs fragment, 66 of these colonies were patched onto R2-4 plates with ampicillin at 50 ug/ml and R2-4 plates with tetracycline at 15 ug/ml and incubated at 37°C overnight. Six of the sixty-six Cm R Amp R colonies showed sensitivity to tetracycline on the patch test. Mini-prep DNA was isolated from these six clones, digested with Hindlll, and analyzed on 0.8% agarose gel. Three of the plasmids showed one 2.5 kb Hindlll insert while the other three showed two or more. The plasmid designated pACYCl84:Pcs showed a single 2.5 kb Hindlll insert. Cesium chloride ethidium bromide gradient purified DNA was isolated from cultures containing this plasmid. Forty ug of pACYC184:Pcs DNA was partially digested with 4 units of BamHI and gel purified. The approximately 6.7 kb fragment, containing linearized plasmid molecules cut at one of the two BamHI sites, was isolated and then digested to completion with SstI. The fragments were gel purified and the 6.7 kb BamHI-SstI fragment, was cut from the gel, electroeluted into O.lx TEA, extracted with phenol/chloroform, precipitated with sodium acetate in ethanol, and resuspended in Tris-EDTA buffer. C. Introduction of a Unique SstI Site into pBR322. Ten micrograms of pBR322 DNA was digested to completion with the restriction endonuclease AlwNI, and the ends were made blunt. SstI (Sac!) linker oligonucleotides from New England Biolabs were ligated with T4 ligase to the blunt-ended pBR322 cut fragment under standard conditions. The ligation mixture was digested directly with 5 units of SstI, gel purified and then ligated to itself with T4 DNA ligase under standard conditions. This ligation mixture was used to transform MM294 competent cells with selection for ampicillin resistance. One culture, MM294 pALF20, gave DNA which was linearized with SstI and was approximately 4.4 kb in length. This plasmid was then used to accommodate the lac and tac promoters. D. Annealing of Oligonucleotides Oligonucleotides were synthesized to form the tac and lac UV5 promoters. Each oligonucleotide contains the sequence for one strand of the promoter, with one strand of an EcoRI half site at one end and one strand of a Hindlll half site at the other. The synthesized oligonucleotides were suspended in H2O to a concentration of 100 pmoles/ul. Two hundred pmoles of each oligonucleotide were treated with 9 units of polynucleotide kinase in a 20 ul reaction containing 1 mM ATP at 37°C for 30 min. Once kinased, the oligonucleotides were mixed together in pairs then heated for 15 min to 68°C to unpair any secondary structure. The oligonucleotides were then allowed to anneal together by cooling to 37°C and incubating for 30 min. After 30 min the annealed oligonucleotides were included in ligation reactions with the pALF20 EcoRI/Hindlll fragment isolated as described below. E. Preparation' of Vector Twenty ug of the plasmid pALF20 were digested with 100 units of EcoRI and 100 units of Hindlll at 37°C for 1.5 hr. The reaction was run on a 0.8% GTG agarose gel and the approximately 4.4 kb fragment, corresponding to linearized DNA, was cut from the gel. The fragment was electroeluted into O.lx TEA buffer in a dialysis bag at 100 volts for 1.5 hr. The DNA and buffer were removed from the bag, extracted with phenol and chloroform, then precipitated with sodium acetate in ethanol. The DNA was dried in a speed vac and resuspended in H2O. - 72 - F. Ligations Each pair of annealed oligonucleotides was ligated to the HindiII/EcoRI-digested pALF20 DNA in a reaction containing 0.1 mM ATP with an insert to vector ratio of 3:1 at 16 β C for 3.5 hr. As a control, the vector EcoRI/HindlII-digested pALF20 was ligated to itself under the same conditions. An aliquot of each ligation mixture was taken before adding the ligase and after ligation for 3.5 hr. These aliquots were run on a 0.8% agarose gel and showed significant increase in molecular weight after 3.5 hr at 16 β C, indicating successful ligation. G. Transformations Each ligation mixture was transformed into DGIOI competent cells and plated on R2-4 plates containing tetracycline at 15 ug/ml. The transformation with the vector ligating on itself gave six tetracycline resistant colonies. pALF20:lacUV5 gave 30 tetracycline resistant colonies, pALF20:tac gave 99. Cesium chloride ethidium bromide gradient purified DNA was prepared from three clones from the pALF20:lacUV5 transformation,, designated pLacl9, pLac20, and pLac21, and the two clones from the pALF20:tac transformation, designated pTac24 and pTac25. These plasmids were sequenced to determine the presence of an annealed oligonucleotide promoter insert: pLac21: Contained the lacUV5 sequence with no errors. pTac25: Contained the tac promoter sequence with a 1 bp mismatch from G to A at the -47 position of the promoter. Plasmids pTac25 and pLac21 were selected to continue construction. Ten ug of each plasmid were - 73 - digested to completion with SstI and then with BamHI. The approximately 1.5 kb fragments containing the ampicillin resistance gene attached to a heterologous promoter (tac or lac) were cut out of the gels, electroeluted into O.lx TEA, extracted with phenol/chloroform, precipitated with sodium acetate in ethanol, and resuspended in Tris-EDTA buffer. H. Ligations The approximately 6.7 BamHI-partial SstI pACY- C184:Pcs vector fragment (isolated in Section B) was ligated to the BamHI/SstI ampicillin resistance heterologous promoter fragments from pLac2l and pTac25 in two separate ligation reactions with insert-to-vector ratios of 7:1 and an ATP concentration of 0.2 mM at 16°C for 24 hr. These two ligation mixtures were used to transform DG101 competent cells. The transformations yielded 786 ampicillin resistant transformants for pACYC184:Pcs:Lac21 and -803 ampicillin resistance transformants from pACY184:Pcs:Tac25. Cultures were grown in R2 with ampicillin at 50 ug/ml from 9 colonies from each tranformation. Alkaline lysis mini-prep DNA was isolated from these cultures and analyzed by restriction digestion with the enzymes BamHI, Hindlll, and SstI. DNAs which corresponded to the restriction map for the plasmids designated pLac21-7 and pTac25-l in Figure 9 were identified. These plasmids were used to transform 1306-21 electrocompetent cell stock. The resulting strains were subjected to Southern blot analysis to verify the chromosomal configuration of these strains, and then used in fermentation experiments to increase levels of cellulose synthase activity and cellulose production. These two strains, along with the untransformed host strain 1306-21, were tested using standard protocols. Strains were tested in duplicate for cell growth, cellulose production and m vitro cellulose activity for days 1, 2 and 5. One hundred twenty-five milliliter baffled flasks were inoculated with a 2% cellulose containing seed media. Standard flask media containing R70-2 with 10 uM FeCl3» 25 mM DMG, 1% TYE and 3% glucose was used. The cultures for the enzyme assays were harvested, the cells passed through cheese cloth, and the cells were washed using previously described protocols. The pellets were frozen as the samples were collected. The cells were sonicated and then assayed for cellulose synthase activity, production of cellulose, and cell growth. The results of this experiment demonstrate that one can replace the Acetobacter chromosomal promoter of the cellulose synthase operon with an E. coli promotor and still obtain in vitro cellulose synthase activity and cellulose production. The in vitro cellulose synthase specific activity of the tac-promoter construct was similar to that of the wild-type cells throughout the fermentation, both in the activity of day-old cultures, and in the decline in activity in the two and five day-old cultures, while the activity of the lac-promoter construct was lower than that of the wild-type strain. Its activity also declined between the first and second days. Cell growth and cellulose production of the tac-promoter construct were experimentally identical to that of the control. The lac-promoter construct was markedly lower in cellulose production, but not in cell growth, as compared to the control. This data suggests - 75 - that production of cellulose in the lac-promoter strain was limited by the in vivo activity of cellulose synthase. Thus, as demonstrated herein, promoters of varying strength may give rise to different enzyme activities and cellulose to cell ratios. Example XVII Experiments With Cellulose Synthase D Gene The purpose of this experiment was to construct a 1306-21 derivative strain for exploration of the function of the cellulose synthase operon D gene. The strain constructed herein can produce a polypeptide from gene D, which lacks 16.5% of the C-terminus of the wild-type protein. A second construction wherein the complete gene D is removed was also constructed. These strains were tested for their phenotype with respect to cellulose production. A. Cloning of a 3.7 kb Fragment Containing Gene C and D Sequences into PACYC184 Twenty ug of pACYC184 DNA were digested with 200 units of EcoRV and 200 units of BamHI in a total volume of 300 ul at 37°C for 2 hr. The DNA was treated with 14 units of calf intestinal alkaline phosphatase at 37° for 30 min, then run on a 1% GTG agarose gel. The approximately 4 kb EcoRV/BamHI fragment was cut from the gel, electroeluted into a small volume of 0.1X TEA at 100 volts for 1 hr, phenol and chloroform extracted, precipitated with sodium acetate in ethanol and resuspended in 10 ul Tris-EDTA buffer. Fifty ug of pBR322:5.5 T19G9 DNA were digested to completion with Smal, checked for complete linearization, and then digested with BamHI. (The 5.5 kb BamHI fragment from TRT11-4 (Example XIV.C) was cloned into the BamHI site of pBR322 to construct pBR322:5.5 T19G9.) The digested DNA was run on a 1% GTG agarose gel, the approximately 3.7 kb fragment (Figure 1 nucleotides 6341-10164), containing the 3' portion of gene C and the complete gene D, was cut from the gel and electroeluted into a small volume of 0.1X TEA at 100 volts for 1 hr. The DNA was then phenol/chloroform extracted, precipitated with sodium acetate in ethanol, and resuspended in 10 ul Tris-EDTA. Approximately 2 ug equivalents -of the pACYC184 BamHI/EcoRV fragment were ligated to approximately 25 ug equivalents of the 3.7 kb BamHI/Smal fragment, at an insert-to- ector ratio of approximately 3:1 with two units of T4 DNA ligase in a 20 ul volume at 16°C for 3.5 hr at an ATP concentration of 100 uM. The ATP concentration was then increased to 1 mM and the ligation mixture incubated overnight at 16°C. .This ligation mixture was used to transform MM294 competent cells under standard conditions. The transformed cells were selected on R2-4 plates containing 20 ug/ml Cm and incubated at 37°C overnight. Cm R transformants were obtained and one or more clones were picked for preparation of alkaline lysis mini-screened DNA. Clone pACYCl84:3.7 was shown to carry a 3.7 kb Smal-BamHl insert containing the 3' end of gene C and all of gene D, including the stem and loop terminator structure at the end of the operon. Cesium chloride ethidium bromide gradient purified DNA was isolated for pACYC184:3.7. B. Interruption of Gene D Sequence Twenty ug of pACYC184:3.7 DNA were digested to - 77 - completion with EcoRV extracted with phenol/chloroform, precipitated and then resuspended in 20 ul of Tris- EDTA. Five ug of pBR322 DNA was digested to completion with EcoRI and AlwNI. The DNA was precipitated and the sticky ends filled-in with Klenow in the presence of all four dNTPs. The filled-in DNA was run on a 1% GTG agarose gel, the 1.5 kb Amp 1 * fragment cut from the gel, electroeluted into 0.1X TEA, phenol/chloroform extracted, precipitated and resuspended in 5 ul Tris-EDTA buffer. The 5 ug equivalents of pBR322 Amp R fragment DNA were ligated to 1 ug equivalent of the pACYC184:3.7 EcoRV-digested DNA at an insert to vector ratio of approximately 9:1 under standard ligation conditions. The ligation mixture was used to transform MM294 competent cells under standard conditions. The transformation was plated on R2-4 Amp 50 plates and incubated at 37° overnight. Amp R colonies were obtained and cultured. Cells were harvested from each culture and alkaline lysis mini-prep DNA was isolated from the cultures. One of the cultures, designated pDI-2, was chosen for transformation of 1306-21. pDI2 contained the Amp resistant fragment from pBR322 inserted in the EcoRV site of pACYC184:3.7, interrupting gene D. Cesium chloride ethidium bromide gradient pDl-2 DNA was prepared. 10 ug of this DNA were digested to completion with Xbal. The digest was washed with 2 ml H2O by spinning at 5,000 rpm in a Centricon 30 (Amicon) . The DNA was then dried in a speed vac and resuspended in 4 ul H2O. Forty ul of electrocompetent 1306-21 cells were added to the digested DNA and the cells electroporated under standard conditions. One ml of R20-2 was added to the - 78 - electroporated cells and the mixture plated immediately on R20-2 Amp 100 Cm 20 plates. After four days incubation at 30°C, approximately 100,000 Amp 11 colonies appeared on the plates. These transformants appeared as weak cellulose producers. Similar results were obtained for the transformants wherein the entire cellulose synthase D gene was deleted. These findings suggest that the cellulose synthesis D gene does play a role in cellulose synthesis. Example XVIII Purification of Cellulose Synthase Strain 1306-27 was grown on a 400 ml 4% fructose, 1% yeast extract, 0.5% Bactopeptone, 0.3% NaH2P0 4 medium, at pH 5.0 in 1000 ml baffled flasks, for 24 hr. Growth media was removed from the cells by washing twice with buffer (50 mM K2HP0 4 , pH 6.0). About 14 g of dry cells were prepared. Cell Membranes Cells (25 mg cells/mL) were ruptured in a French press in the presence of polyethyleneglycol (PEG) and TME buffer, 20% PEG (w/v) . The broken cells were centrifuged (12,000 x g, for 10 min) and the pellet was resuspended in TME buffer to the same volume. This suspension was homogenized (Potter Elevehjem homogenizer) and the suspension was centrifuged (12,000 x g, for 10 min). The resulting pellet contained the cellulose synthase activity. This sample (P-PEG) was resuspended in TME buffer to a concentration corresponding to 50 mg cell weight per ml and was frozen in liquid nitrogen and stored at -80°C. Trypsin Treatment P-PEG was centrifuged (12,000 x g, 10 min) and the pellet was suspended in 0.1 M Tris, pH 8.3, 20% sucrose to 10 mg cells dry weight/ml. A 1% volume of 8 mg/ml trypsin (Sigma) was added and the preparation incubated with gentle shaking for 1 hr at 4°C. A 1% volume of 2 mg/ml trypsin inhibitor was added and the preparation was incubated for 15 min on ice. After centrifugation (100,000 x g, for 30 min) the pellet (TT-P-PEG) was stored frozen at -80°C. Solubilization A 10% solution of digitonin (Serva, Westbury, NY) in TME buffer was prepared by heating for 5-10 min in a boiling bath and the preparation was then cooled to 4°C. The TT-P-PEG pellet was suspended to 1/10 the original volume in TME buffer containing 2% digitonin. The suspension was sonified at 4°C for 2 min using a MSE Model 140 sonifier. Sonification was carried out on 30 ml portions in 30 sec sonic pulses with intermittent cooling. The suspension was shaken and mixed gently for 90 min and then centrifuged at 200,000 x g for 60 min. The supernatant contained approximately ' 50% of original cellulose synthase activity. When frozen and stored as above, activity was retained for several months. Enzyme Concentration The solubilized enzyme was concentrated 5-7 fold using Amicon cones (Filter lOOK) to an activity of 10-16 enzyme units/ml (unit = 1 nanomole/min) . The concentrated enzyme was kept overnight at 4°C or frozen as above. - 80 - Enzyme-product Entrapment To the bottom of each of six 40 ml centrifuge tubes for the Contron TST-28 (swinging bucket) rotor, were added 26 ml of the glycerol-containing cushion (TME buffer (pH 8.5) containing 12-13% glycerol, 1 mM UDPG and 15 umole c-di-GMP) and 10 ml reaction mixture (50 ml solubilized enzyme, 6.25 mmole Tris-HC buffer, pH 9.6, 340 umole CaCl2» 1 mmole " gCl2, 0.6 umole c-di-GMP, and 60 umole UDPG to a final volume of 61 ml) were gently layered on it. The tubes were incubated for 15 min at 30°C, then placed on ice for 2.5 hr, and finally centrifuged in a TST-28 Contron rotor for 30 minat 20,000 rpm. (The centrifuge was set to decelerate to 350 rpm in 3-4 min.) The supernatants were carefully decanted. The pellets were combined and suspended in 15 ml TME with a manual homogenizer and recentrifuged. The final pellet was suspended in 5 ml TME. Before SDS-PAGE, the entrapped enzyme was washed once by centrifugation. The entrapped enzyme was stable for several weeks when frozen and stored as above. The activity yield of entrapped enzyme was about 45%. Separation of Proteins on SDS-PAGE Entrapped enzyme, containing 12-15% of original cellulose synthase activity, was dissolved in Laemmli's sample buffer (containing DTT), and subjected to SDS-PAGE in 10% acrylamide slab gels. The peptide bands were visualized by Coomassie-Blue staining and excised. Four major bands were observed, Band A 90-95 kd, Band B 65-68 kd, Band C 58-60 kd, and Band D 54-56 kd. The gel slices were sealed in plastic bags containing 10% acetic acid for storage. Recovery of the Protein from the SDS-PAGE Gel Slices The proteins were separated from the SDS-PAGE gel slices by electroelution, using a method modified from Hunkapiller, et al. (Methods in Enzymology, 1983, 91:227-247). The method was adapted to result in a lower final SDS concentration. The modifications were: 1) substitution of elution buffer (0.1% SDS in 0.05 M NH HC03) for the soaking buffer (2% SDS in 0.05 M NH 4 HC03); and 2) when replacing the elution buffer (0.1% SDS in 0.05 M NH HC03) in the apparatus with dialysis buffer (0.02% SDS in 0.01 M NH 4 HC0 3 ) , most of the buffer in the sample " cell was also replaced, carefully avoiding disturbing the sample. Example XIX N-Terminal Amino Acid Sequence of The Polypeptides Protein Isolated From The Cellulose Synthase Preparation The first 18 amino acids of the 90-95 kd protein and the first 16 amino acids of the 65-68 kd protein purified from Acetobacter strain 1306-27 were sequenced by automated Edman degradation on an Applied Biosystems model 470A Protein Sequencer, using the reagents and protocol supplied by the manufacturer. The 18 amino acids of the 90-95 kd protein match an amino acid sequence predictedfrom the DNA sequence of cellulose synthase obtained as described above. The match begins with the alanine residue indicated in Figure 1. The amino-terminus obtained after purification may not be the actual in vivo N-terminus, but may reflect proteolysis at the lysine preceding this alanine. The deduced sequence of the cloned gene codes for a protein of 83 kd. Some additional peaks for the early amino acids near the N-terminus were present, possibly due to contamination. The quality of the sequence obtained for the 65-68 kd protein was not as high as that obtained for the 90-95 kd protein, but a good match may be made between the 65-68 kd protein N-terminal sequence and the amino acids (designated by the brackets) from the sequence predicted in Figure 1. Thus, the 65-68 kd protein appears to be a proteolytic fragment of the 90-95 kd protein. The following cultures have been deposited at the American Type Culture Collection, (ATCC) Rockville, MD, USA, under* the terms of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure and Regulations thereunder (Budapest Treaty) and are thus maintained and made available according to the terms of The Budapest Treaty. Availability of such strains is not to be construed as a license to practice the invention in contravention of the rights granted under the authority of any government in accordance with its patent laws. The deposited cultures have been assigned the indicated ATCC .deposit numbers. The cultures have also been deposited with the Master Culture Collection (CMCC) of Cetus Corporation, Emeryville, CA, USA, the assignee of the present application, and assigned the indicated CMCC deposit numbers: Culture CMCC No. ATCC No Acetobacter 1306-24 pUC18-824 FS6 3538 67925 E. coli DG101 pUC18-824 FS6 3581 67926 Acetobacter strain 1306-3 1909 53264 Acetobacter strain 1306-11 2145 53263 Acetobacter strain 1306-21 2618 53524 E. coli DG98 1965 39768 E. coli DG101 pϋC18-824 pABCD 68264 While the present invention has been illustrated above by certain specific embodiments, it is not intended that these specific examples limit the scope of the invention as described in the appended claims.

Claims: We claim: 1. An isolated native, cloned recombinant or synthetic polynucleotide sequence encoding a bacterial cellulose synthase operon. 2. The polynucleotide of claim 1 which is derived from the genome of Acetobacter. 3. The polynucleotide of claim 1 which comprises four contiguous genes, wherein, with reference to Figure 1, the first gene corresponds -substantially to nucleotides 328 to 2589, the second gene corresponds substantially to 2594 to 4999, the third gene corresponds to substantially nucleotides 5005 to 8961, and the fourth gene corresponds substantially to nucleotides 8964 to 9431. 4. The polynucleotide of claim 1 which further comprises a DNA sequence encoding a promoter located adjacent to and upstream from the first gene of said operon. 5. The polynucleotide of claim 4 wherein said promoter is endogenous to Acetobacter. 6. The polynucleotide of claim 5 wherein said endogenous promoter is derived from the cellulose synthase operon. 7. The polynucleotide of claim 4 wherein said promoter is a heterologous bacterial promoter. 8. The polynucleotide of claim 7 wherein said heterologous promoter is selected from the group comprising tac and lac. 9. The polynucleotide of claim 1 which further comprises a DNA sequence encoding a transcription terminator. 10. The polynucleotide of claim 9 wherein said transcription terminator is located within about 26 basepairs 3' of the termination codon of the fourth gene. 11. The polynucleotide of claim l which is operably linked to a control sequence for expression. 12. The polynucleotide of claim 11 wherein said control sequence is derived from bacteria. 13. The polynucleotide of claim 12 wherein the bacteria are selected from the group consisting of Acetobacter and Escherichia. 14. Recombinant host cells transformed with the polynucleotide of claim 11. 15. The transformed host cell of claim 14 which is a bacterial cell. 16. The transformed host cell of claim 15 which is an E. coli or Acetobacter cell. 17. An isolated native, cloned recombinant or synthetic polynucleotide substantially corresponding to the nucleotide sequence for cellulose synthase A, as shown in Figure 1. 18. The polynucleotide of claim 17 substantially corresponding to nucleotides 328 to 2589 as shown in Figure 1. 19. An isolated native, cloned recombinant or synthetic polynucleotide substantially corresponding to the nucleotide sequence for cellulose synthase B, as shown in Figure 1. 20. The polynucleotide of claim 19 substantially corresponding to nucleotides 2594 and 4999, as shown in Figure 1. 21. An isolated native, cloned recombinant or synthetic polynucleotide substantially corresponding to the nucleotide sequence for cellulose * synthase C as shown in Figure 1. 22. The polynucleotide of claim 21 substantially corresponding to nucleotides 5005 to 8961, as shown in Figure 1. 23. An isolated, native, cloned recombinant or synthetic polynucleotide substantially corresponding to the nucleotide sequence for cellulose synthase D, as shown in Figure 1. < < 24. The polynucleotide of claim 23 substantially corresponding to nucleotides 8964 to 9431, as shown in Figure 1. 25. The polynucleotide of claim 17 which is operatively linked to a control sequence for expression. 26. The polynucleotide of claim 19 which is operatively linked to a control sequence for expression. 27. The polynucleotide of claim 21 which is operatively linked to a control sequence for expression. - 87 - 28. The polynucleotide of claim 23 which is operatively linked to a control sequence for expression. 29. A recombinant host cell transformed with the polynucleotide of claim 25. 30. A recombinant host cell transformed with the polynucleotide of claim 26. 31. A recombinant host cell transformed with the polynucleotide of claim 27. 32. A recombinant host cell transformed with the polynucleotide of claim 28. 33. A method for producing bacterial cellulose synthase comprising culturing the transformed cells of claim 14 under conditions suitable for the expression of bacterial cellulose synthase, and recovering the expressed bacterial cellulose synthase from the culture. 34. A method for producing bacterial cellulose synthase comprising culturing the transformed cell of claim 30 under conditions suitable for the expression of bacterial cellulose synthase, and recovering the expressed bacterial cellulose synthase from the culture. 35. The method of claim 34 wherein said polynucleotide has the sequence corresponding to nucleotides 2594 to 4999, as shown in Figure 1. 36. An isolated, recombinant protein having an approximate molecular weight of 85 kilodaltons and capable of synthesizing β(l-4)-glucan polymers from uridine 5'-diphosphoglucose, wherein said protein shares substantial amino acid sequence homology with that provided for cellulose synthase B shown in Figure 1. 37. An isolated protein having an approximate molecular weight of 84 kilodaltons, substantially free of proteins associated with its native environment, which protein is capable of complementing cellulose negative Acetobacter cells defective in both cellulose synthase and diguanylate cyclase activities,, said protein further characterized as sharing substantial amino acid sequence homology with that provided for cellulosse synthase A shown in Figure 1. 38. An isolated protein having an approximate molecular weight of 141 kilodaltons, substantially free of proteins associated with its native environment, which protein is capable of synthesizing and secreting β(l-4) glucan polymers from uridine 5'-diphosphoglucose in vivo, when said protein is combined in appropriate proportions ' with the remaining three proteins of the cellulose synthase operon, said protein further characterized as sharing substantial amino acid sequence homology with that provided for cellulose synthase C shown in Figure 1. 39. An isolated protein having an approximate molecular weight of 17 kilodaltons, substantially free of proteins associated with its native environment, which is capable of synthesizing and secreting β(l-4) glucan polymers from uridine 5'-diphosphoglucose in vivo when said protein is combined in appropriate proportions with the remaining three proteins of the cellulose synthase operon, said protein further characterized as sharing substantial amino acid sequence homology with that provided for cellulose synthase D shown in Figure 1. 40. A method for increasing cellulose production in a recombinant microorganism, which method comprises: a) transforming a suitable microorganism with a vector comprising at least one gene derived from the cellulose synthase operon, and b) culturing said transformed microorganism under conditions suitable for production of cellulose. 41. The method of claim 41 wherein said gene comprises the four genes encoded by the cellulose synthase operon. 42. The method of claim 40 wherein said polynucleotide is operably linked to a control sequence for expression of said cellulose synthase operon. 43. The method of claim 42 wherein said control sequence comprises a heterologous promoter. 44. The method of claim 43 wherein said heterologous promoter is a regulated promoter. 45. The method of claim 44 wherein said regulated promoter is selected from the group consisting of lac and tac promoters. 46. The method of claim 45 wherein said regulated promoter is the lac promoter and the recombinant microorganism further comprises a polynucleotide encoding the lac! gene product. 47. The method of claim 42 wherein said host cell is a bacterial cell. 48. The method of claim 47 wherein said bacterial cell is an Acetobacter cell. 49. The method of claim 48 wherein said Acetobacter cell has a cellulose synthase negative phenotype. 50. The process of claim 48 wherein said Acetobacter cell has a cellulose synthase positive phenotype. 51. A recombinant DNA vector comprising: a) a functional Acetobacter origin of replication-containing fragment of plasmid p824, and b) one or more DNA segments that convey resistance to at least one antibiotic when transformed into a sensitive host cell that is susceptible to transformation, cell division and culture. 52. The recombinant DNA vector of claim 51 which further comprises a functional replicon of an E. coli plasmid. 53. The recombinant DNA vector of claim 51 which further comprises a nucleic acid sequence encoding the bacterial cellulose synthase operon which is operably linked to a ' control sequence for expression. 54. * The recombinant DNA vector of claim 53 which is pUClβ-824 FSl or pUC18-824 FS6. 55. Recombinant bacterial host cells transformed with the recombinant DNA vector of claim 51. 56. The recombinant bacterial host cell of claim 55 which is an Acetobacter or Escherichia species.

Inventors: BEN-BASSAT ARIE, BENSIMAN MOSHE, CALHOON ROGER D, FEAR ANNA LISA, GELFAND DAVID H, MEADE JAMES H, TAL RONY, WONG HING, BEN-BASSAT, ARIE, BENSIMAN, MOSHE, CALHOON, ROGER, D., FEAR, ANNA, LISA, GELFAND, DAVID, H., MEADE, JAMES, H., TAL, RONY, WONG, HING
Applicants: CETUS CORP, CETUS CORPORATION
Application year: 1990
Main classification: C12N15
IPC codes: C07K14, C12N1, C12N9, C12N15