bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature-sensitive mutants of herpes simplex virus type 1 defective in lysis but not in transformation
Authors: Hughes R G , Munyon W H
Published: January 2020

Twelve temperature-sensitive (ts) mutants of herpes simplex virus type 1 (HSV-1), representing seven complementation groups, were isolated subsequent to 5-bromodeoxyuridine mutagenesis. These mutants were identified by their inability to replicate in a line of monkey (CV-1) cells at 39 C. Seven of these mutants, representing six complementation groups, induced thymidine kinase (tk) and transformed Ltk- cells, a line of mouse L cells lacking tk, to a tk+ phenotype at both the permissive (34 C) and nonpermissive (39 C) temperatures. Thus, the defective cistrons in these six complementation groups, although necessary for lysis, have no essential function in this transformation system. Transformation by these 12 mutants was dependent on prior UV irradiation. Infection of cells with unirradiated virus under conditions which did not permit virus replication was not sufficient to allow cell transformation. Five mutants, representing two complementation groups, were tk- and were incapable of causing the tk--to-tk+ transformation at either 34 C of 39 C. The tk defects in these mutants are probably unrelated to the ts defects, since one of these complementation groups contains a tk+ member. Therefore, transformation of Ltk- cells to a tk+ phenotype by HSV-1 requires an active viral tk gene. One complementation group was represented by a single tk- member. The role of this cistron in transformation remains undetermined since the primary block to transformation is presumed to be the tk- phenotype. Mutants representing the seven complementation groups were unable to replicate at 39 C in two lines of HSV-1-transformed cells, indicating that the activities of resident wild-type copies of the defective cistrons, if present, could not be detected by complementation.
Synthesis of functional bacteriophage T4-delayed early mRNA in the absence of protein synthesis
Authors: Morse J W , Cohen P S
Published: January 2020

When Escherichia coli B207 is grown either aerobically or under limited aerobic conditions, pretreated with chloramphenicol to block protein synthesis, and then infected with bacteriophage T4, the phage RNA which accumulates, termed "immediately early" (IE), contains the transcripts of a limited number of prereplicative genes. Among the transcripts which accumulate is the mRNA which serves as a template for deoxycytidylate hydroxymethylase (HMase) synthesis. Among the prereplicative gene transcripts which do not accumulate under these conditions are deoxycytidine triphosphatase (dCTPase), alpha-glucosyl transferase (alphg-gt), and deoxynucleotide kinase (kinase); these genes have been termed "delayed early" (DE). In contrast, when protein synthesis is inhibited by depleting aerobically grown E. coli B207 of K+, both IE and DE T4 RNA accumulate, but these transcripts do not contain functional HMase, dCTPase, alpha-gt, or kinase mRNA's. However, if E. coli is grown under conditions of limited aeration and then depleted of K+ prior to T4 infection, the T4 RNA which accumulates contains both IE and DE transcripts and functional HMase, dCTPase, and alpha-gt mRNA's. Functional kinase mRNA does not accumulate under these conditions. The results of these experiments indicate that the synthesis of functional DE RNA in the absence of simultaneous protein synthesis, depends on the physiological condition of the cells and the way in which protein synthesis is inhibited. In addition, data is presented which suggests that extensive transcription of DE genes in the absence of protein synthesis results in the inhibition of transcription of certain IE genes.
Proteins synthesized by Semliki Forest virus and its 16 temperature-sensitive mutants
Authors: Keränen S , Kääriäinen L
Published: January 2020

The proteins synthesized in chicken embryo fibroblasts infected with wild-type Semliki Forest virus and 16 temperature-sensitive mutants derived from it were studied by polyacrylamide gel electrophoresis. In addition to the structural proteins, five nonvirion proteins (NVP) with molecular weight of 130,000, 97,000, 86,000, 78,000 and 62,000 were found varying amounts in cells infected with the different RNA+ mutants and also in the wild-type-infected cells. Pulse-chase experiments suggested that NVP 130, NVP 97, NVP 86, and NVP 62 are precursors presumably of the structural proteins. The amount of NVP 78 was not affected by the chase, and it may represent a translational product of the nonstructural part of the genome. The NVP 130 was shown to be a common precursor of the structural proteins by tryptic peptide mapping. Kinetic evidence from one of the mutants (ts-3) suggested that NVP 86 is one of the precursors of the capsid protein. A common feature of all the RNA+mutants was the inability to cleave the NVP 62 into E2 and E3, suggesting that this cleavage is a crucial reaction in the virus maturation.
Further evidence for the existence of a viral envelope protein defect in the Bryan high-titer strain of Rous sarcoma virus
Authors: Ogura H , Friis R
Published: January 2020

Electron microscopy observations of purified Bryan high-titer Rous sarcoma virus (BH RSV) using the freeze-drying technique showed that progeny made in the absence of a helper virus lacked visible surface projections or spikes. Phenotypic mixing experiments employing BH RSV and a thermolabile mutant of vesicular stomatitis virus, tl 17, yielded no evidence of pseudotype formation. Since tl 17 is known to be defective for an envelope glycoprotein, the lack of successful phenotypic mixing with BH RSV is consistent with the observed absence of viral spikes.
Association of Ribosomes with Intracellular Vesicular Stomatitis Virus Particles
Authors: Orenstein J. , Shelton E. , Lazzarini R. A.
Published: January 2020

Ribosomes are observed intimately associated with nucleocapsids of vesicular, stomatitis virus, especially those that line structures that are either cytoplasmic vesicles or invaginations of the plasma membrane.
Production of antibody to individual polypeptides derived from purified hepatitis B surface antigen
Authors: Dreesman G R , Chairez R , Suarez M , Hollinger F B , Courtney R J , Melnick J L
Published: January 2020

Purified preparations of hepatitis B surface antigen (HBsAg) were solubilized with sodium dodecyl sulfate and urea under reducing conditions and subsequently fractionated by preparative sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis (PAGE). Pools of the individual fractions eluted from the preparative PAGE were concentrated and purified further by analytical PAGE. Five purified polypeptides were isolated from HBsAg, types adw and ayw, with molecular weights of 19,000, 24,000, 27,000, 35,000, and 40,000. Each preparations was emulsified in Freund complete adjuvant and injected into guinea pigs. Antibody to each HBsAg type was measured by radioimmunoassay. The 19,000 molecular weight polypeptide derived from ayw particles and the 27,000 molecular weight subunit obtained from both types failed to elicit an antibody response. The other three polypeptides derived from the ayw particles elicited group-specific antibody responses. Similar group-specific reactivities were observed in the testing of anti-adw 35,000 and anti-adw 40,000 molecular weight polypeptide sera. However, guinea pigs immunized with the 19,000 and the 24,000 molecular weight polypeptides of the adw type produced antibody that reacted preferentially with adw particles. This indicates that either these subunits carry predominately d determinants or that, because of the low levels of material used for inoculation, no immune response or an undetectable one was elicited to the a or w components.
Site on the RNA of an avian sarcoma virus at which primer is bound
Authors: Taylor J M , Illmensee R
Published: January 2020

In vitro transcription of the avian tumor virus RNA by RNA-directed DNA polymerase is initiated on the unique cellular 4S RNA. Previous studies have shown that on the average there is one such RNA primer hydrogen bonded to each viral 35S RNA. The present study confirms that finding and demonstrates that, at least for the majority of 35S RNA molecules, the primer is bound at a site close to the 5'-terminus.
Physical map and strand polarity of specific fragments of adenovirus-associated virus DNA produced by endonuclease R-EcoRI
Authors: Carter B J , Khoury G , Denhardt D T
Published: January 2020

Cleavage of adenovirus-associated virus type 2 (AAV2) DNA linear duplex monomers with the restriction endonuclease R-EcoRI yielded three fragments, A, B, and C, having approximate mol wt of 1.6 X 10(6), 1.1 X 10(6), and 1.3 X 10(5), respectively. Radioactive labeling the 5' termini of AAV DNA before cleavage with R-EcoRI showed that A and B were terminal fragments and C was internal. Separation of the complementary strands of fragments A and B showed that A contained the 5' terminus of the minus strand and the 3' terminus of the plus strand, and conversely for fragment B. The physical map of the AAV R-EcoRI fragments can thus be unambiguously determined and is drawn with B at the left-hand and A at the right-hand end. On this map, transcription of stable AAV mRNA from the minus strand proceeds from left to right, beginning in fragment B and terminating in fragment A. The asymmetry in distribution of thymidine between the AAV DNA plus and minus strands is preferentially located in fragment A, which represents the right-hand half of the duplex molecule. These experiments enable preparative separation of all four single-strand termini of AAV DNA and provide a basis for orientation of fragment maps derived by cleavage with other restriction enzymes.
Effect of impaired glycosylation on the biosynthesis of Semliki forest virus glycoproteins
Authors: Kaluza G
Published: January 2020

The glycoproteins of Semliki Forest virus, grown in chicken embryo cells, were labeled with radioactive sugars. The data indicate a high mannose content of the nonstructural precursor glycoprotein NSP 63. This protein can also be readily labeled with 2-deoxy-D-glucose. The envelope glycoproteins E1 and E2 are relatively rich in galactose, glucosamine, and fucose. Glycosylation can be impaired by 2-deoxy-D-glucose or D-glucosamine or by omission of sugars in the culture medium. Under these conditions characteristic changes in the electrophoretic profile of the viral polypeptides are observed: in the regions of glycoproteins NSP 97, NSP 63, and E1 and E2 new protein peaks can be detected. These polypeptides seem to be aberrant forms of the glycoproteins. When compared with the normal molecules they have lower molecular weights and contain less carbohydrates, especially mannose. Pulse-chase experiments indicate that the altered glycoproteins are degraded very slowly if at all. If, however, impairment is caused by omission of sugars in the culture medium, the radioactivity is chased after addition of glucose from the region between NSP 63 and E1 + E2 into the E1 + E2 peak. This suggests a completion of the carbohydrate chains under these conditions.
Biochemical studies on bovine adenovirus type 3. I. Purification and properties
Authors: Niiyama Y , Igarashi K , Tsukamoto K , Kurokawa T , Sugino Y
Published: January 2020

Bovine adenovirus type 3 (BAV3) was purified and its properties were studied. On productive infection of CKT1 cells (a cell line derived from calf kidney) with BAV3, it was observed that viral DNA synthesis was initiated after about 24 h and its rate was maximal after about 40 h. Maturation of the virus occurred several hours after this. Purified BAV3 was separated into four discrete bands by CsCl density gradient centrifugation (complete, incomplete, empty, and degraded viruses). The complete BAV3 was similar in size and structure to human and avian adenoviruses. Polyacrylamide gel electrophoresis showed that the complete BAV3 virion contained at least 10 polypeptides. The total structural proteins of the virion had a similar amino acid composition to those of human adenoviruses. DNA of the complete virus was a linear duplex and its contour length was 12.3 +/- 0.9 mum. The So20,w value of the DNA was 32.9S and its buoyant density in CsCl was 1.717 g/ml. There was about 25% homology between the DNAs of BAV3 and human adenovirus type 5 by filter hybridization. It was also noted that BAV3 produced incomplete virus. The incomplete virus was similar in morphology to the complete virus and contained almost all the structural polypeptides of the latter, but lacked infectivity. However, its DNA had a deletion(s) (13%) which seemed to locate near a terminal.
Denaturation map of polyoma DNA
Authors: Lescure B , Yaniv M
Published: January 2020

A denaturation map of polyoma DNA cleaved by Eco R1 to form linear molecules was established by electron microscopy. Partial denaturation, under the same conditions, of fragments obtained by Haemophilus influenzae restriction enzymes allowed us to align the denaturation map with the already established physical map of polyoma DNA (Griffin et al., 1974).
Low frequency of (5'-3') -C-G- connection in 70S RNA from simian sarcoma virus
Authors: Ohe K , Oppenheim L B
Published: January 2020

The frequency of oligonucleotides obtained from simian sarcoma virus RNA by digestion with ribonuclease T1 was compared with the frequency expected of an RNA molecule in which nucleotides are arranged in random distribution. Oligonucleotides containing C-residue attached to 3'-Gp were found significantly less in simian sarcoma virus 70S RNA than expected by random distribution.
Molecular weight of DNA from actinophage MSP2
Authors: Lancaster W D , Jones L A
Published: January 2020

Actinophage MSP2 is infectious for Streptomyces venezuelae S13. Based upon electron microscopy of coliphage T4 mixed with MSP2, MSP2 had a head about 48 +/- 2 nm wide and 87 +/- 5 nm long. DNA from polyoma virus and from coliphages T4 and T7 served as reference markers in estimating the molecular weight of MSP2 DNA from sedimentation in sucrose gradients. Denatured MSP2 DNA was estimated to be about 17 x 10(6) and double-stranded MSP2 DNA was about (36 +/- 1.6) x 10(6) in molecular weight.
Polyadenylic acid sequences in rhinovirus RNA species from infected human diploid cells
Authors: Macnaughton M R , Dimmock N J
Published: January 2020

Polyadenylic acid sequences were shown to be present in rhinovirus virion RNA. Virus-specified RNA from human embryo lung cells infected with rhinovirus also contained polyadenylic acid but did not contain any polyuridylic acid sequences.
Biochemical properties of the bromodeoxyuridine-induced guinea pig virus
Authors: Michalides R , Schlom J , Dahlberg J , Perk K
Published: January 2020

The biophysical and biochemical properties of the virus particles released by guinea pig embryo cells treated with 5-bromo-2'-deoxyuridine (BUdR) have been compared to those of the B-type mouse mammary tumor virus (MMTV) and the C-type Rauscher murine leukemia virus. The high-molecular-weight (60 to 70S) RNA of the BUdR-induced guinea pig virus (GPV) has a molecular weight of 8 X 106 when measred by mixed agarose polyacylamide gel electrophoresis. The virus particles isolated from the tissue culture medium of BUdR-induced guniea pig cells have the following properties in common with MMTV: (i) a buoyant density of 1.18 g/ml in sucrose and 1.21 g/ml in CsCl, and (ii) a DNA polymerase that prefers Mg2+ over Mn2+ in an assay using the synthetic template poly(rC):oligo(dG). No nucleic acid sequence homology between GPV RNA and the viral RNAs of the MMTV, murine leukemia virus, hamster sarcoma virus, or Mason-Pfizer monkey virus could be observed in a competition hybridization assay using the radioactive-labeled GPV 60 to 70S RNA. By this same competition by hybridization assay the frequency of GPV proviral sequences was estimated to be at least 83 per haploid cellular genome of guniea pig cells. No nucleic acid sequences related to be GPV RNA were detected in the DNA of normal tissues of mice, rats, cats, dogs, baboons, or humans by direct RNA-DNA hybridization using radioactive GPV60 to 70S RNA.
Murine intracisternal type A particles: a biochemical characterization
Authors: Wong-Staal F , Reitz M S , Trainor C D , Gallo R C
Published: January 2020

Intracisternal A particle preparations from a murine neuroblastoma cell line (N18) and from a mineral oil-induced murine plasmacytoma (MOPC-104E) contain both an endogenous RNA-dependent DNA polymerase activity and high molecular-weight polyadenylic acid (poly[A])-containing RNA. The DNA polymerase activity is stimulated by oligo(dG)-poly(C) and oligo(dT)-poly(A) and to a lesser extent by oligo(dT)-poly(dA), in agreement with previous reports. The high-molecular-weight RNA is predominantly 35S and contains a poly(A) tract of approximately 220 nucleotides as judged by polyacrylamide gel electrophoresis. Small amounts of 70S RNA are also present. This RNA preparation contains RNA homologous to RNA from type-C particles, as judged by molecular hybridization experiments. However, since this RNA derives only in part from A-particles and in part from other cellular RNA, hybridization of A-particle endogenously synthesized DNA or reverse transcripts of A-particle RNA to purified type C viral 70S RNA may more accurately reflect the relationship of A-particle RNA to RNA from C-particles. None of these DNA transcripts hybridizes significantly to C-particle 70S RNA, although MOPC and N18 DNA transcripts share significant homology. Our interpretation of these results is that murine intracisternal A particles are not closely related genetically to the tested murine type C viruses, although an alternate possibility is that all the A-particle DNA transcripts are copied from only a small part of the genome, which is unrelated to C-particle RNA.
Interfering passages of Sindbis virus: concomitant appearance of interference, morphological variants, and trucated viral RNA
Authors: Johnston R E , Tovell D R , Brown D T , Faulkner P
Published: January 2020

Serial passage of Sindbis at high multiplicities of infection resulted in cyclical variations in virus titer. Decreases in virus titer were correlated with the appearance of smaller-sized virions, interference and truncated viral RNA. The smaller particles were 37 nm in diameter, exclusive of the hemagglutinin spikes as compared with a diameter of 50 nm for standard virions. Passages which contained 37-nm partilces also interfered with infectious center formation by standard, plaque-purified virus. Polyacrylamide gel analysis of RNA isolated from virions present in interfering passages demonstrated the sequential appearance of three RNA species smaller than standard RNA with approximate molecular weights of 3.3 X 106, 2.7 X 106, and 2.2 X 106. The 3.3 X 106 RNA was evident in passage 5, by passage 8 both the 3.3 X 106 and 2.7 X 106 RNAs were present, and by passage 13 all three were present with the 2.2 X 106 RNA predominating.
Analysis of expression of the rII gene function of bacteriophage T4
Authors: Heere L J , Karam J D
Published: January 2020

Temperature-sensitive (ts) mutants of the T4 phage rII gene were islated and used in temperature shift experiments that revelaed two different expressions for the normal rII (rII+) gene function in vivo: (i) an early expression (0 to 12 min postinfection at 30 C) that prevents restriction of T4 growth in Escherichia coli hosts lysogenic for gamma phage, and (ii) a later expression (12 to 18 min postinfection at 30 C) that results in restriction of T4 growth when the phage DNA ligase (gene 30) is missing. The earlier expression appeared to coincide with the period of synthesis of the protein product of the T4 rIIA cistron, whereas the later expression occurred after rIIA protein synthesis had stopped. The synthesis of the protein product of the rIIB cistron continues for several minutes after rIIA protein synthesis ceases (O'Farrell and Gold, 1973). The two rII+ gene expressions might require different molar ratios of the rIIA and rIIB proteins. It is possible that the separate expressions of rII+ gene function are manifestations of different associations between the two rII proteins and other T4-induced proteins that are synthesized or activated at different times after phage infection.
Long-term persistence of cytomegalovirus genome in cultured human cells of prostatic origin
Authors: Rapp F , Geder L , Murasko D , Lausch R , Ladda R , Huang E S , Webber M M
Published: January 2020

Cells from prostatic tissue obtained from a 3-year-old male donor exhibited scattered foci of cytopathology on primary culture. A virus was isolated and shown by serological analysis to be cytomegalovirus (CMV). After a number of cell culture passages, a cell line (disignated CMV-Mj-P) was obtained in which foci of infection could no longer be demonstrated, nor could virus be rescued. On continued passage the doubling time of the cells decreased markedly, and the fibroblastoid cells ceased to demonstrate contact inhibition. CMV-specific antigen(s) was detected on the surface of the cells by indirect immunofluorescence techniques after exposure of the cultures to iododeoxyuridine. Microcytotoxocity tests established that CMV-Mj-P cells, but not control human prostate cells or human embryonic lung cells, share a membrane antigen with hamster cells transformed by CMV. Nucleic acid hybridization studies revealed that virus genetic information was carried by the human prostate cells and that the cells contained an average of about 10 to 15 genome equivalents of CMV DNA. Karyotypic analysis confirmed that the CMV-Mj-P cells were of human male origin. These results indicate that the cells either have been transformed by CMV or are chronically infected with CMV and releasing virus at levels below detection.
Biochemical and biophysical characteristics of diarrhea viruses of human and calf origin
Authors: Rodger S M , Schnagl R D , Holmes I H
Published: January 2020

Polyacrylamide gel electrophoretic analysis of purified preparations of human and calf diarrhea viruses indicated eight polypeptide components, or possibly nine in the case of the calf diarrhea virus. Thermal denaturation and analytical studies of the calf diarrhea virus genome showed it to consist of 11 double-stranded segments of RNA. The placing of the human and calf diarrhea viruses together with other similar viruses into a genus separate from reovirus and orbivirus, but within the family Reoviridae, is discussed.
Thymineless bacteriophage induction in Staphylococcus aureus. I. High-frequency transduction with lysates containing a bacteriophage related to bacteriophage phi 11
Authors: Rudin L , Lindberg M
Published: January 2020

A thymine-requiring mutant of Staphylococcus aureus, strain 8325 (PI258)thy, undergoes prophage induction and lysis after thymine starvation. Four different phages were isolated from the lysate in low titers, among which was a phage designated phi 14, which differs from phage phi 11 in its immunity locus. The thymineless induced lysates of strain 8325(PI258)thy transduce the penicillinase plasmid at high frequency (10(-1), whereas transduction of chromosomal markers is inefficient. A plasmic-cured derivative of strain 8325(PI258)thy is also lysed by thymine starvation and be used for high-frequency transduction of other plasmids. Reconstitution of a strain of S. aureus that responds to thymine starvation was only partially successful, but this system can effectively be used to transduce plasmids or plasmid derivatives.
Alkali lability of bacteriophage phi W-14 DNA
Authors: Lewis H A , Miller R C , Stone J C , Warren R A
Published: January 2020

The molecular weight of bacteriophage phi W-14 DNA, determined by velocity sedimentation in neutral sucrose gradients, was 92 +/- 6 X 10(6). The DNA showed marked fragmentation in alkaline sucrose gradients. This fragmentation was not a consequence of preexisting single-strand interruptions in the DNA, since thermal denaturation of DNA yielded intact single strands. The alpha-putrescinylthymine groups in phi W-14 DNA appeared to be labile; some, or parts of some, of these groups were cleaved from the DNA in alkali.
Bacteriophage T4 baseplate components. I. Binding and location of the folic acid
Authors: Kozloff L M , Lute M , Crosby L K
Published: January 2020

Two different proteins with high affinities for the pteridine ring of folic acid have been used to determine the location of this portion of the folate molecule in the tail plate of T4D and other T-even bacteriophage particles. The two proteins used were (i) antibody specific for folic acid and (ii) the folate-binding protein from bovine milk. Both proteins were examined for their effect on various intact and incomplete phage particles. Intact T2H was weakly inactivated by the antiserum but not by the milk protein. No other intact T-even phage, including T4D, was affected by these two proteins. When incomplete T4D particles were exposed in an in vitro morphogenesis system, it was found that neither of the two proteins affected either the addition of the long tail fibers to fiberless particles or the addition of tail cores to tail plates. On the other hand, these two proteins specifically blocked the addition of T4D gene 11 product to the bottom of T4D baseplates. After the addition of the gene 11 protein, these two reagents did not inhibit the further addition of the gene 12 protein to the baseplate. It can be concluded that the phage folic acid is a tightly bound baseplate constituent and that the pteridine portion of the folic acid is largely covered by the gene 11 protein.
Bacteriophage T4 baseplate components. II. Binding and location of bacteriophage-induced dihydrofolate reductase
Authors: Kozloff L M , Crosby L K , Lute M , Hall D H
Published: January 2020

The location of T4D phage-induced dihydrofolate reductase (dfr) has been determined in intact and incomplete phage particles. It has been found that phage mutants inducing a temperature-sensitive dfr (dfrts) procude heat-labile phage particles. The structural dfr produced by these ts mutants was shown to assume different configurations depending on the temperature at which the phage is assembled. Morphogenesis of incomplete phage particles lacking the gene 11 protein on their baseplates was found to be inhibited by reagents binding to dfr, such as antibodies to dfr. Further, cofactor molecules for dfr, such as reduced nicotinamide adenine dinucleotide phosphate and reduced nicotinamide adenine dinucleotide, also inhibited the step in morphogenesis involving the addition of gene 11 product. On the other hand, inhibitors of dfr, such as adenosine dephosphoribose, stimulated the addition of the gene 11 protein. It has been concluded that the phage-induced dfr is a baseplate component which is partially covered by the gene 11 protein. The properties of phage particles produced after infection of the nonpermissive host with the one known T4D mutant containing a nonsense mutation in its dfr gene suggested that these progeny particles contained a partial polypeptide, which was large enough to serve as a structural element.
Bacteriophage P22 virion protein which performs an essential early function. I. Analysis of 16-ts mutants
Authors: Hoffman B , Levine M
Published: January 2020

The product of gene 16 of phage P22, P16, is a head protein. P16 does not play an essential role in phage assembly since particles formed without this protein appear normal by electron microscopy examination (Botstein et al., 1973). P16 is essential when the particle infects a cell in the following cycle of infection (Botstein et al., 1973; King et al., 1973). We have characterized a mutant of P22 carrying a temperature-sensitive allele of gene 16. This mutant has previously been referred to as P22 25-ts (Levine et al., 1970, 1972) and P22 X-ts (Bezdek and Soska, 1970, 1973). P22 16-ts behaves as an early mutant at the nonpermissive temperature. Temperature shift experiments show that P16 of the infecting virion acts within the first 10 min at 25 C and that gene 16 product is required late in the latent period for incorporation into infectious phage. Induction does not require P16 for the production of particles. Particles produced either in a P22 16-ts thermal shift-up infection or after induction of 16-ts lysogens at 41 C are missing P16 and are, therefore, defective. P16 in P22 16-ts virions formed at the permissive temperature appears to be heat labile; it is inactivated after infection at 41 C. A simple assay for defective particles based on a complementation test is described.
5′ Nucleotide Sequence of Sindbis Viral RNA
Authors: Hefti Elisabeth , Bishop D. H. L. , Dubin D. T. , Stollar V.
Published: January 2020

The 5′ sequence of Sindbis viral RNA is m
7
G
5′
pppApUpGp...
Differential Inhibition of Vesicular Stomatitis Virus Polypeptide Synthesis by Hypertonic Initiation Block
Authors: Nuss Donald L. , Koch Gebhard
Published: January 2020

Synthesis of the vesicular stomatitis virus membrane matrix protein and the glycoprotein is inhibited to a greater extent than the synthesis of the nucleocapsid protein, the nonstructural protein, and the large protein when the rate of peptide chain initiation is reduced by exposure of vesicular stomatitis virus-infected cells to hypertonic medium. It is concluded that the relative sensitivity of individual viral polypeptide synthesis to hypertonic initiation block is independent of the site of synthesis, i.e., whether on membrane-associated or free polyribosomes.
In Vitro Transcription of 70
S
RNA by the RNA-Directed DNA Polymerase of Rous Sarcoma Virus: Lack of Influence of RNase H
Authors: Collett Marc S. , Faras Anthony J.
Published: January 2020

The influence of Rous sarcoma virus (RSV)-associated RNase H on the in vitro synthesis of DNA by the RSV RNA-directed DNA polymerase was determined under conditions whereby RNase H activity was selectively inhibited with NaF. Not only were we unable to detect any effect on the size, structure, or genetic complexity of the DNA product synthesized in the absence of RNase H activity, but the displacement of DNA from the 70
S
RNA:DNA hybrid structures was also unaffected. The suitability of 70
S
RNA:DNA hybrid structures synthesized in vitro to serve as a substrate for RNase H is discussed.
Molecular Weights of DNA from Bacteriophages T5, T5
st
(0), BF23, and BF23
st
(4)
Authors: Lang Dimitrij , Shaw Alan R. , McCorquodale D. James
Published: January 2020

The DNA molecular weights were determined by calibrated electron microscopy. The results (in units of 10
6
) are: for T5, 77.4 ± 2.4; T5
st
(0), 72.4 ± 1.9; BF23, 76.7 ± 2.3; and BF23
st
(4), 71.4 ± 1.7.
5′-Terminal Sequence of Vesicular Stomatitis Virus mRNA's Synthesized In Vitro
Authors: Rhodes Dennis P. , Banerjee Amiya K.
Published: January 2020

Unmethylated or methylated 12 to 18
S
mRNA's synthesized in vitro by the virion-associated RNA polymerase of vesicular stomatitis virus contain the 5′-terminal hexanucleotide sequence G(5′)ppp(5′)ApApCpApGp... or m
7
G(5′)ppp(5′)Ap
m
ApCpApGp..., respectively. The implication of these results in relation to the regulation of transcription in vesicular stomatitis virus is discussed.
High Spontaneous Mutation Rate of an Avian Sarcoma Virus
Authors: Zarling David A. , Temin Howard M.
Published: January 2020

Three genetically distinct types of chicken sarcoma virus Bratislava 77 (B77 virus) differing in their ability to infect duck cells were identified. B77 virus type I does not infect duck cells; B77 virus type II has a low efficiency of infection of duck cells; and B77 virus type III has a high efficiency of infection of duck cells. B77 viruses type I and III are produced by spontaneous mutation during the growth of B77 virus type II in chicken cells. The spontaneous mutation of B77 virus type II to B77 virus type III occurs with a high rate (approximately 1 mutation per 50 infected cell generations), requires cell replication, and neither occurs during the synthesis of viral DNA on an RNA template nor during the transcription of progeny viral RNA from the provirus. The rate of spontaneous mutation of B77 virus type II to B77 virus type I is greater than the rate of spontaneous mutation of B77 virus type II to B77 virus type III.
T7 Protein Synthesis in F-Factor-Containing Cells: Evidence for an Episomally Induced Impairment of Translation and Its Relation to an Alteration in Membrane Permeability
Authors: Blumberg Daphne D. , Mabie Cheryl T. , Malamy Michael H.
Published: January 2020

T7 infection of F-factor-containing PIFA
+
,B
+
cells is abortive. In spite of the presence of mRNA for all three classes of T7 proteins, only the earliest of the T7 proteins are synthesized. A crucial question is whether the failure of T7 to develop in PIFA
+
,B
+
cells is the result of an inability to translate the late classes of T7 mRNA or, as has been recently suggested (Britton, and Haselkorn, 1975; Condit, 1975), whether it is the result of a more generalized alteration in membrane permeability. We have examined the effects of the wild-type PIFA
+
,B
+
episome and two episomal mutations (
pifA
−
and
pifB
−
) on in vitro translation and membrane permeability. In vivo the episomal mutations allow partial or complete T7 development to occur. We demonstrate that cell-free protein-synthesizing systems from T7-infected PIFA
+
,B
+
cells show a three- to fivefold decrease in the rate of translation of both natural and synthetic mRNA. In addition, ribosomes from T7-infected PIFA
+
,B
+
cells are defective in their ability to bind Fmet tRNA
f
in response to natural mRNA. By contrast, cell-free extracts from T7-infected
pifA
−
(PIFA
−
,B
+
) cells retain the ability to bind Fmet tRNA
f
and to translate natural and synthetic mRNA at normal rates. The defective T7-infected PIFA
+
,B
+
ribosomes can be restored to full activity by a trypsin-sensitive fraction from uninfected PIFA
+
,B
+
or T7-infected PIFA
−
,B
+
cells. Despite the differences in translational capacity of these extracts, both T7-infected PIFA
+
,B
+
and PIFA
−
,B
+
cells display the same permeability lesions as measured by the loss of ATP from the cells into the supernatant. Mutation of the episome to
pfiB
−
prevents the loss of ATP from the cells after T7 infection.
Recovery of the accumulation ability of thiomethyl-beta-galactoside in Escherichia coli after bacteriophage T4 infection
Authors: Saijo N , Okamoto K
Published: January 2020

Effects of UV-irridiated and unirradiated T4 phage infection on the beta-galactoside accumulation ability in Eschericia coli have been examined by the use of 14C-labeled thiomethyl-beta-galactoside (TMG). Under conditions where a synchronous adsorption of phage takes place, the cellular ability for TMG accumulation is found to be largely inhibited immediately after phage adsorption, but it recovers with time to a new level, which is dependent on the multiplicity of infection. When cells are infected with UV-irradiated T4 at the same multiplicity as that of unirradiated phage, the cellular accumulation ability is more severely inhibited and there is no recovery from the inhibition. The recovery process in T4-infected cells is mostly sensitive to puromycin. These results suggest that the initial inhibition of the TMG accumulation ability is probably caused by the adsorption of phage coats, and the subsequent restoration occurs through the action of a phage-directed protein(s). In the recovery process, no new transport system appears to be involved. The restored ability of TMG accumulation is resistant to the action of superinfecting UV phage. However, different mechanisms appear to be operating in T4-infected cells for the establishment of resistance to ghosts and for the recovery from the phage coat-induced inhibition.
Effect of the "RNA control" locus in Escherichia coli on RNA bacteriophage R23 replication
Authors: Ernberg J , Sköld O
Published: January 2020

The effect of the rel gene of Escherichia coli on the RNA synthesis induced by phage R23 was studied. This RNA phage has the property of inhibiting ribosomal RNA formation and completely dominating the RNA synthesis of the host. Phage-specific RNA formation was found to be dependent on the allelic state of the rel gene. Determinations of RNA synthesis were made by both cumulative and short-term incorporations of uracil and adenine. Variations in labeling of nucleotide pools were compensated for by determining specific activities of ATP and UTP and using these values to obtain true, relative rates of RNA synthesis.
Isoaccepting species of serine tRNA coded by bacteriophage T5sto
Authors: Henckes G , Panayotakis O , Heyman T
Published: January 2020

By aminoacyl-tRNA-DNA hybridization and chromatographic analysis, evidence was provided that the bacteriophage T5stO codes for two tRNAser species. Trinucleotide- or polynucleotide-stimulated binding experiments assigned the codons UCC or UCU to these two tRNAser species. They also suggested that the synthesis of these two tRNAser species does not modify the reading capacity for codons less used in Escherichia coli F and corresponds to a different situation compared with the T4-coded tRNA's.
Rat sequences of the Kirsten and Harvey murine sarcoma virus genomes: nature, origin, and expression in rat tumor RNA
Authors: Anderson G R , Robbins K C
Published: January 2020

Two murine sarcoma viruses, the Kirsten and the Harvey, were isolated by passage of mouse type C leukemia viruses through rats. These sarcoma viruses have genomes containing portions of their parental type C mouse leukemia virus genomes, in stable association with specific rat cellular sequences that we find to be quite likely not those of a rat type C leukemia virus. To determine if these murine sarcoma viruses provide a model relevant to the events occurring in spontaneous tumors, we have hybridized DNA and RNA prepared from rat tumors and normal rat tissues to [3H]DNA prepared from the Kirsten murine sarcoma virus. We have also hybridized these rat tissue nucleic acids to [3H]DNA prepared from a respresentative endogenous rat type C leukemia virus, the WFU (Wistar-Furth). Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected in the DNA of both tumor and normal tissues, with no evidence of either gene amplification or additional sequences being present in tumor DNA. Sarcoma-viral rat cellular sequences and endogenous rat leukemia viral sequences were detected at elevated concentrations in the RNA of many rat tumors and in specific groups of normal tissues.
Effect of medium of lowered NaCl concentration on virus release and protein synthesis in cells infected with reticuloendotheliosis virus
Authors: Bishop J M , Maldonado R L , Garry R F , Allen P T , Bose H R , Waite M R
Published: January 2020

When cultures producing reticuloendotheliosis virus were incubated for 24 h in medium of lowered NaCl concentration, virus production was inhibited. The extent of inhibition increased as the salt concentration of the medium was decreased. The inhibition was rapidly reversed by replacement of low-salt medium with normal medium. During the first hour after the inhibited cultures were returned to normal medium, virus was released at an accelerated rate, making the total amount of virus released by inhibited and control cultures the same. After 1 h in normal medium, the rate of virus production in the previously inhibited cultures was the same as in the control cultures. Incubation of infected cells in low-salt medium resulted in a 60% decrease in the overall rate of protein synthesis. Although returning the cells to normal medium rapidly reversed the inhibition of virus production, it did not rapidly increase the rate of protein synthesis. These results suggest that host cell-directed protein synthesis is preferentially inhibited by the low-ionic-strength medium, whereas that required for virus production continues.
Mason-Pfizer virus RNA genome: relationship to the RNA of morphologically similar isolates and other oncornaviruses
Authors: Colcher D , Drohan W , Schlom
Published: January 2020

The 60-70S RNA of Mason-Pfizer virus (MPV) was iodinated in vitro and used in both direct and competitive molecular hybridization studies. MPV proviral sequences are present at a frequency of approximately one to two copies per haploid genome in the DNA of experimentally infected human cells. By nucleic acid competition hybridization, MPV RNA was found to be indistinguishable from the RNA of a virus (X381) isolated from a rhesus mammary gland and from RNA isolated from the cytoplasm of AO cells (Parks et al., 1973) and HeLa cells (Gelderblom et al., 1974), both previously reported to produce MPV-related particles. No homology was observed, however, between MPV RNA and the RNA, or the DNA, from two clones of HeLa cells obtained from the American Type Culture Collection. Hybridization of MPV 60-70S RNA to the DNA of normal tissues of humans and to the DNA of 11 other species revealed that MPV is not an endogenous virus of any of these species. Competition hybridization revealed no detectable sequence homology between the RNA of MPV and the RNAs of simian sarcoma virus, murine mammary tumor virus, murine leukemia virus, BUdR-induced guinea pig virus, or avian myeloblastosis virus. These nucleic acid studies substantiate previous ultrastructural and immunological findings that MPV and morphologically similar isolates constitute a distinct group of oncornavirus.
Comparison of the serology, transforming ability, and polypeptide composition of human papovaviruses isolated from urine
Authors: Wright P J , Bernhardt G , Major E O , di Mayorca G
Published: January 2020

Four isolates of human papovaviruses (RF, GS, DW, and MG viruses) obtained from the urine specimens of renal allograft recipients in widely separated locations were compared with BK virus. Hemagglutination inhibition tests and plaque neutralization assays showed that all were antigenically related to BK virus. All isolates transformed baby hamster kidney cells, transformation being determined by the ability of the cells to plate in soft agar. Purified preparations of each isolate were iodinated with chloramine T and the polypeptide compositions were compared by electrophoresis of disrupted viruses in polyacrylamide gels containing sodium dodecyl sulfate. The gel patterns of all isolates were similar to that of BK virus. The tryptic digests of two major iodinated virion proteins, VP1 and VP3, were analyzed on an ion exchange column. The peptide patterns of GS, DW, and BK virus were identical; those of RF and MG virus closely resembled the patterns of the above three with only minor differences in some peptides. The results show that the four isolates and BK virus are antigenically closely related, have similar onocogenic potential, and are distinguishable from simian virus 40 and JC virus.
Quantitation of the viral DNA present in cells transformed by UV-irradiated herpes simplex virus
Authors: Davis D B , Kingsbury D T
Published: January 2020

Two cell lines biochemically transformed by UV-irradiated herpes simplex virus (HSV) each contain virus DNA. A comparison of the kinetics of reassociation of 3H-labeled HSV DNA in the presence and absence of either clone 139 (HSV-1 transformed) or clone 207 (HSV-2 transformed) DNA showed that the presence of transformed cell DNA increased the rate of reassociation of approximately 10% of the viral genome while having no effect on the remaining 90%. The Cot1/2 of this reaction was approximately 1,000 in each cell type, as compared to approximately 3,000 for the cellular unique sequences. These results suggest the presence of four to six copies of a 10% fragment of the virus DNA per cell. The DNA from a hamster fibroblast cell line morphologically transformed by UV-irradiated HSV-2 (333-8-9) did not affect the rate of reassociation of HSV-2 DNA, indicating that these cells had less than 3% of a viral genome present.
Group-specific antigen shared by the members of the reticuloendotheliosis virus complex
Authors: Maldonado R L , Bose H R
Published: January 2020

The polypeptides of reticuloendotheliosis virus (REV) were separated by gel filtration in the presence of guanidine hydrochloride. The eight peaks obtained by gel filtration were then analyzed by polyacrylamide gel electrophoresis and four appeared to contain single polypeptides. The material identified as p29 was used to prepare antiserum. This protein constitutes the major internal non-glycosylated polypeptide in the virion. Double immunodiffusion indicated that the antiserum was specific for p29. Using this antiserum, cross-reactivity was demonstrated between REV, chick syncytial virus, duck infectious anemia virus, and spleen necrosis virus. Antiserum to p29 failed to cross-react with Rous sarcoma virus. This indicates that p29 is a group-specific antigen shared by the viruses of the REV complex. A microcomplement fixation test was developed with this antiserum that will be useful in the quantitation of REV and the identification of other members of this newly defined group.
Membrane proteins specified by herpes simplex viruses. I. Identification of four glycoprotein precursors and their products in type 1-infected cells
Authors: Spear P G
Published: January 2020

Polypeptide precursors to the major glycoproteins specified by herpes simplex virus type 1 were identified in immunoprecipitation experiments using antisera that reacted specifically with the viral glycoproteins and their precursors. The results demonstrate that the major glycosylated proteins detected in infected cells are derived from four antigenically distinct polypeptides. Three of these polypeptides become glycosylated in two discrete stages, yielding partially glycosylated intermediates and fully glycosylated products. The final products are the predominant species detected in cytoplasmic virions and in plasma membranes. The fourth polypeptide precursor appears to acquire very little carbohydrate and differs in several respects from the other three precursors.
DNA polymerase activities induced by polyoma virus infection of 3T3 mouse fibroblasts
Authors: Närkhammar M , Magnusson G
Published: January 2020

Resting mouse 3T3 fibroblasts were stimulated to synthesize DNA either by infection with polyoma virus or by injection of fresh serum. Changes in the levels of DNA polymerase (alpha-, beta-, and gamma-enzymes) were measured in the cytoplasm and the cell nucleus. Both types of stimulation gave very similar increases for all three enzyme activities. In the cell nucleus, both alpha- and gamma-polymerases increased almost tenfold, whereas the beta-enzyme only was stimulated twofold. In the cytoplasm alpha- and gamma-polymerases increased two- to four-fold. Only insignificant amounts of the beta-enzyme were found in the cytoplasm.
Pleiotropic effects of mutants in gene A of bacteriophage phi chi 174
Authors: Funk F D , Snover D
Published: January 2020

It has previously been established that the functional gene A product of phi chi X 174 is required for double-stranded DNA replication and that mutants in gene A affect the lysis of the host cell. We report here other alterations of normal phenotype for a subset of gene A mutants suggesting additional functions of gene A. Mutants in the subset failed to terminate cellular DNA synthesis and were unable to efficiently inactivate the colony-forming ability of the host. Two mutants in a second group retained the ability to kill the infected cell, although only one of these mutants efficiently terminated cellular DNA synthesis. Normal termination of cellular DNA synthesis did not occur by the production of random multiple breaks in the DNA, although it may have occurred by the selective production of breaks in newly synthesized DNA. It has previously been shown that two protein products are produced from the gene A region, the smaller of which is a C-terminal fragment of the larger. The separate phenotypes reported here for the two groups of mutants in gene A are consistent with separate functions for the two gene products previously reported.