bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure, expression, and regulation of members of the developmentally controlled V and H gene classes from Dictyostelium
Authors: Singleton Charles K. , Delude Russel L. , Ken Ruey , Manning Suzanne S. , McPherson Clifton E. 
Published: May 2005

AbstractWe have examined the expression and structure of vegetative specific genes belonging to the V and H gene classes. Both classes of genes are deactivated at the onset of development by a reduction in the rate of transcription. Thus, the genes must be reactivated when the terminally differentiated spores germinate and the resulting amebae return to the vegetative state. During germination, activation of expression of most members of the V gene class was found to parallel the emergence of amaebae from the spore coats. The activation of the V genes did not occur when protein synthesis was inhibited. The timing of activation of the H genes was more heterogeneous and did not parallel emergence. H gene activation occurred even when protein synthesis was inhibited. V4 was found to be the only vegetative specific gene that was responsive to the presence of bacteria. V4 expression was induced by 25–100 fold via transcriptional activation when bacteria were added to amebae growing axenically. Isolation and sequence analysis of the corresponding genomic clones revealed that two V genes, V18 and V1, encode ribosomal proteins. Promoter analysis has delineated the sequences necessary for expression and regulation for several of the V and H genes. In all cases, expression was determined by sequences within the first several hundred base pairs of the transcription start site. For V18 and V14, a positive constitutive element was identified in addition to the sequences involved in regulation. Finally, all of the characterizations and findings are discussed in terms of postulated models for V and H gene expression and regulation.
Cyclic nucleotide phosphodiesterase of Dictyostelium discoideum and its glycoprotein inhibitor: Structure and expression of their genes
Authors: Franke Jakob , Faure Michel , Wu Lin , Hall Anne L. , Podgorski Gregory J. , Kessin Richard H. 
Published: May 2005

AbstractThe genes coding for the cyclic nucleotide phosphodiesterase (PD) and the PD inhibitory glycoprotein (PDI) have been cloned and characterized. The PDI gene was isolated as a 1.6 kb genomic fragment, which included the coding sequence containing two small introns and 510 nucleotides of non‐translated 5′ sequence. From the deduced amino acid sequence we predict a protein with a molecular weight (MW) of 26,000 that, in agreement with previous data, contains 15% cysteine residues. Genomic Southern blot analysis indicates that only one gene encodes the inhibitor. Northern blot analysis shows a single transcript of 0.95 kb. The PDI gene is expressed early in development with little transcript remaining following aggregation. The appearance of PDI mRNA is prevented by the presence of cAMP, but when cAMP is removed the transcript appears within 30 minutes. When cAMP is applied to cells expressing PDI the transcript disappears with a half‐life of less than 30 minutes. The PD gene of D. discoideum is transcribed into three mRNAs: a 1.9 kb mRNA specific for growth, a 2.4 kb mRNA specific for aggregation, and a 2.2 kb mRNA specific for late development. The 2.2 kb mRNA is also specific for prestalk cells, and is induced by differentiation‐inducing factor. All three mRNAs contain the same coding sequence, and differ only in their 5′ non‐coding sequences. Each mRNA is transcribed from a different promoter, and by using the chloramphenicol acyltransferase gene as a reporter, we have shown that each promoter displays the same regulation as its cognate mRNA. Transformation of wild‐type strains with the PD gene causes PD overexpression which accelerates aggregation and blocks subsequent cell differentiation and pattern formation.
Coordinate regulation of the spore coat genes in Dictyostelium discoideum
Authors: Fosnaugh Kathy L. , Loomis William F. 
Published: May 2005

AbstractGenomic clones of the genes coding for the three major spore coat proteins, SP60, SP70, and SP96, were used to measure the accumulation of their respective mRNAs in mutant and wild‐type cells allowed to develop under a variety of conditions. These prespore‐specific mRNAs were found to be both temporally and quantitatively coordinate under all conditions indicating that they may be subject to identical regulatory processes. Accumulation of the spore coat mRNAs is dependent upon the function of both cAMP receptors and Gα2 proteins during the aggregation stage as well as upon concomitant protein synthesis. When cells are dissociated from aggregates at 10 hr of development and rapidly shaken in 0.1 mM EDTA they form clumps but do not accumulate any of the prespore‐specific RNAs assayed. However, if either 0.1 rnM Ca++ or 20 μM cAMP is added to these cells, the spore coat mRNAs accumulate. Lower concentrations of either Ca++ or cAMP had no effect. These results suggest that expression of the spore coat genes normally involves a Ca++ ‐dependent process, but the Ca++ requirement can be overcome by adding Ca++ high concentrations of exogenous CAMP.Addition of 50 nM DIF to dissociated cell blocks the accu‐ mulation of the spore coat mRNAs even when cAMP or Ca++ is present. The upstream regions of the spore coat genes were compared to those of another gene, D19, that codes for the prespore‐specific protein SP29. Short sequences related to CACCCAC were found at about the same position relative to the transcriptional start sites of these co‐ ordinately regulated genes.
Ras‐related genes in Dictyostelium discoideum
Authors: Robbins Stephen M. , Khosla Meenal , Thiery Richard , Weeks Gerald , Spiegelman George B. 
Published: May 2005

AbstractDicfyostelium discoideum, like other eukaryotes, has been shown to express several ras‐related genes. Two gene products, Ddras and DdrasG, are highly conserved relative to the human ras proteins. Ddras is expressed at the pseudoplasmodial stage of development, whereas DdrasG is expressed in vegetative cells and during early development. In addition, Dicfyostelium possesses three ras‐related genes, SAS1, SAS2 and Ddrap1, whose gene products are only partially conserved relative to those of the ras genes. The expression of these three genes is also developmentally regulated.
Regulation of cysteine proteinases during different pathways of differentiation in cellular slime molds
Authors: North Michael J. , Cotter David A. 
Published: May 2005

AbstractCysteine proteinase activities have been determined using gelatin‐SDS‐PAGE analysis and assays based on peptide nitroanilides. Vegetative myxamoebae of all species examined contain high levels of cysteine proteinose activity present in multiple forms. In both Dictyostelium discoideum and Polysphondylium pallidum the proteinase content is dependent on whether the cells are grown axenically or in association with bacteria. In all instances development is accompanied by a decreased intracellular cysteine proteinase activity. This occurs during the formation of fruiting bodies in D. discoideum, microcysts in P. pallidum, and macrocysts in Dictyostelium mucoroides. Significant quantities of proteinase activity are always secreted by myxamoebae immediately on starvation. In D. mucoroides this leads to an almost total depletion of intracellular cysteine proteinases by the aggregation stage. As a consequence of this depletion it has been relatively easy to detect a developmentally regulated accumulation of cysteine proteinases at the enzyme activity level, something which has not yet proved possible with D. discoideum. Three cysteine proteinases are produced as D. mucoroides macrocysts develop and mature. In the case of microcyst formation in P. pallidum the proteinase contents of the developing cells and of the microcysts are dependent on how the myxamoebae are grown. In this developmental pathway at least, there is no absolute requirement for specific proteinases to be present (or absent) at a particular stage. The diversity of cysteine proteinases found in cellular slime molds and the variety of features apparent in their regulation suggest that they will prove to be very useful for investigating features of the structure/function relationships in this important group of enzymes.
Structure, expression, and inactivation by gene disruption of the Dictyostelium discoideum prespore gene EB4
Authors: Hildebrandt Martin , Saur Uschi , Nellen Wolfgang 
Published: May 2005

AbstractWe present the nucleotide sequence of the cell type specific prespore gene EB4 which encodes a protein containing a hydrophobic leader sequence and two distinct domains of amino acid repeats. By RNase protection experiments we have determined the genomic organization of the gene which differs substantially from the previously published data. An antibody directed against one of the repeat structures (hexamer repeat) specifically reacts with a developmentally regulated antigen of 58 kd. Gene disruption transformants were obtained by transformation with a genomic DNA fragment. The transformants express a 3′ truncated mRNA and do not react with the anti‐hexamer antibody. So far, we could not detect any phenotypic aberrations in the transformed cell line.
Lethal(1)aberrant immune response mutations leading to melanotic tumor formation in Drosophila melanogaster
Authors: Watson Kellie L. , Johnson Terrell K. , Denell Robin E. 
Published: May 2005

AbstractUsing P element‐mediated mutagenesis we have isolated 20 X‐linked lethal mutations, representing at least 14 complementation groups, which exhibit melanotic tumor phenotypes. We present the systematic analysis of this interesting group of lethal mutations that were selected for their visible melanotic or immune response. The lethal and melanotic tumor phenotypes of each lethal(1) aberrant immune response (air) mutation are pleiotropic effects of single genetic lesions. Lethality occurs throughout the larval and early pupal periods of development and larval development is extended in some air mutants. The air mutant lethal syndromes include abnormalities associated with the brain, haematopoietic organs, gut, salivary glands, ring glands, and imaginal discs. Additional characterization of the melanotic tumor mutations Tuml and tu(1)Szts have indicated that the melanotic tumor phenotype is similar to that observed in the air mutants. These studies have led to the proposal that two distinct classes of melanotic tumor mutations exist. Class 1 includes mutants in which melanotic tumors result from “autoimmune responses” or the response of an apparently normal immune system to the presence of abnormal target tissues. The Class 2 mutants display obvious defects in the haematopoietic organs or haemocytes, manifested as overgrowth, and the resulting aberrant immune system behavior may contribute to melanotic tumor formation.
Differential expression and isozymic composition of sn‐glycerol‐3‐phosphate dehydrogenase in tissues from variant lines of Drosophila melanogaster
Authors: Cook Julia L. , Shaffer Jacquelin B. , Bewley Glenn C. 
Published: May 2005

AbstractThe tissue‐specific expression and isozymic composition of Drosophila sn‐glycerol‐3‐phosphate dehydrogenase (GPDH) (EC 1.1.1.8) have been determined for a high‐activity control line and two variant lines that alter either the temporal or systemic expression of GPDH through a reduction in rates of polypeptide synthesis. The temporal variant exhibits a reduction in enzyme levels in all larval tissues and in the adult abdomen, while levels of activity in the adult thorax are equal to the control line. Isozymic analyses of these tissues demonstrate that it is the GPDH‐3 species that is reduced in a temporal and tissue‐specific manner. In contrast, the systemic variant demonstrates a uniform reduction of all isozymic species in each tissue and developmental stage. Analyses of the tissues of F1 hybrid offspring of each variant line and appropriately marked electrophoretic variants demonstrate that the tissue‐specific effects observed are due to cis‐acting elements that are tightly linked to the structural gene.
Maternal effect mutations affecting macronuclear determination and development in Paramecium tetraurelia
Authors: Berger James D. , Havelka Monika 
Published: May 2005

AbstractGene mutations that interfere with macronuclear development in Paramecium were obtained by selecting lines that failed to produce normal macronuclear anlagen following the second autogamy after mutagenesis. The mutants fell into several complementation groups. There was one case of apparent intragenic noncomplementation among the eight mutants examined. In the stronger mutants, macronuclear anlagen were not formed, and all four mitotic products of the posfzygotic divisions of the synkaryon remained as micronuclei. Under semirestrictive conditions, cells often contained a single anlage, suggesting that determination of anlagen was a discrete event for each nucleus. The missing anlagen trait was recessive and associated with a strong maternal effect. The phenocritical period of one of the stronger alleles, aala, began at the second postzygotic division and ended with the first morphological differentiation of macronuclear anlagen. Nuclear migration in this mutant was abnormal. Under restrictive conditions, the posterior products of the second postzygotic division reached a posterior‐most position, which was 8% of cell length more anterior than that of the most posterior nuclei in wild‐type cells. Under permissive conditions, the pattern of migration was intermediate between that of wild‐type cells and mutants under fully restrictive conditions. The patterns of nuclear migration were consistent with the nuclear growth kinetics.
Generating lineage‐specific markers to study Drosophila development
Authors: Perrimon Norbert , Noll Elizabeth , McCall Kimberly , Brand Andrea 
Published: May 2005

AbstractTo generate cell‐ and tissue‐specific expression patterns of the reporter gene lacZ in Drosophila, we have generated and characterized 1,426 independent insertion strains using four different P‐element constructs. These four transposons carry a lacZ gene driven either by the weak promoter of the P‐element transposase gene or by partial promoters from the even‐skipped, fushi‐tarazu, or engrailed genes. The tissue‐specific patterns of β‐galactosidase expression that we are able to generate depend on the promoter utilized. We describe in detail 13 strains that can be used to follow specific cell lineages and demonstrate their utility in analyzing the phenotypes of developmental mutants. Insertion strains generated with P‐elements that carry various sequences upstream of the lacZ gene exhibit an increased variety of expression patterns that can be used to study Drosophila development.
Analysis of developmentally interesting genes cloned from higher plants by insertional mutagenesis
Authors: Chandlee Joel M. 
Published: May 2005

AbstractThe ability of transposable elements to generate gene mutations by excising from one site in the genome and reintegrating into new, different sites elsewhere in the genome has led to the development of procedures whereby the elements can be used to tag specific gene sequences for eventual isolation and analysis through gene cloning. This transposon tagging strategy is particularly useful in those situations where limited knowledge of the biochemistry of the target gene precludes gene cloning by conventional strategies. This approach, in conjunction with the more general insertional mutagenesis approach using T‐DNA, has led to the cloning and subsequent analysis of several genes from higher plants involved in particular developmental processes. Studies of this nature should eventually shed light on the precise molecular mechanisms utilized to regulate and control cellular differentiation in plants.
Cellular morphogenesis in the Saccharomyces cerevisiae cell cycle: Localization of the CDC11 gene product and the timing of events at the budding site
Authors: Ford Susan K. , Pringle John R. 
Published: May 2005

AbstractThe Saccharomyces cerevisiae CDC3, CDC10, CDC11, and CDC12 genes encode a family of homologous proteins that are not closely related to other known proteins [Haarer BK, Ketcham SR, Ford SK, Ashcroft DJ, and Pringle JR (submitted)]. Temperature‐sensitive mutants defective in any of these four genes display essentially identical pleiotropic phenotypes that include abnormal cell‐wall deposition and bud growth, an inability to complete cytokinesis, and a failure to form the ring of 10 nm filaments that normally lies directly subjacent to the plasma membrane in the neck region of budding cells. We showed previously that the CDC3 and CDC12 gene products localize to the region of the mother‐bud neck and are probably constituents of the ring of 10 nm filaments. We now report the generation of polyclonal antibodies specific for the CDC11 product (Cdc11p) and the use of these antibodies in immunofluorescence experiments with wild‐type and mutant cells. The results suggest that Cdc11p is also a constituent of the filament ring, and thus support the hypothesis that the S. cerevisiae 10 nm filaments represent a novel type of eukaryotic cytoskeletal element. Cdc11p and actin both localize to the budding site well in advance of bud emergence and at approximately the same time, and both proteins also remain localized at the old budding site for some time after cytokinesis. Cdc11p also localizes to regions of cell‐wall reorganization in mating cells and in cells responding to purified mating pheromone. Surprisingly, most preparations of affinity purified Cdc11p‐specific antibodies also stained the nuclear and cytoplasmic microtubules. Although this staining probably reflects the existence of an epitope shared by Cdc11p and some microtubule‐associated protein, the possibility that a fraction of the Cdc11 p is associated with the microtubules could not be eliminated.
Expression of gap junction genes during postnatal neural development
Authors: Belliveau Daniel J. , Kidder Gerald M. , Naus Christian C. G. 
Published: May 2005

AbstractThe timing of appearance of mRNAs encoding gap junction proteins was examined during development of the rat and mouse brain. Complementary DNAs (cDNAs) specific for the mRNA for the liver‐type gap junction protein, connexin32, and the heart‐type gap junction protein, connexin43, were used to probe Northern blots of total RNA isolated from the forebrain and hindbrain of mice and rats at various times before and after birth. Prior to postnatal day 10, connexin32 mRNA is detectable only at low levels. By postnatal days 10 to 16, a sharp increase occurs in the level of this mRNA. This increase is detectable first in the hindbrain, and subsequently in the forebrain. In contrast, connexin43 mRNA is readily detectable at birth, and the level of this mRNA also increases during subsequent development. The developmental appearance of the gap junction proteins, connexin32 and connexin43, was similar to that of their respective mRNAs. These results indicate that the genes encoding connexin32 and connexin43 are differentially expressed during neural development.
Sequence of swallow, a gene required for the localization of bicoid message in Drosophila eggs
Authors: Chao Yu‐Chan , Donahue Kathleen M. , Pokrywka Nancy J. , Stephenson Edwin C. 
Published: May 2005

AbstractWe report the sequence of the Drosophila maternal effect gene swallow, one of the genes whose product is required for the localization of bicoid message during Drosophila oo‐genesis. The inferred swallow protein contains a domain that is predicted to be an amphipathic α‐helix similar to those implicated in protein:protein associations in other systems. Another part of the predicted protein appears to be a diverged RNA‐binding motif. We discuss these structural features in light of the function of the swallow protein in the bicoid message localization process.
Phenotypic consequences and genetic interactions of a null mutation in the Drosophila posterior Sex Combs gene
Authors: Adler Paul N. , Martin Elisabeth C. , Charlton Jeannette , Jones Katherine 
Published: May 2005

AbstractThe Posterior Sex Combs (Psc) gene of Drosophila is a member of the Polycomb (Pc) group of transregulatory genes. Previous analyses of the function of this gene in Drosophila em‐bryogenesis have been hampered by the lack of a null mutation. We recently isolated a mutation that deletes the 5′ end of the Psc gene. This allele appears to be a null mutation, and we have used it to determine the Psc zygotic null phenotype and to look at the interactions of a null allele of Psc with five other Pc group mutations. We find evidence for transformations along both the anterior‐posterior and dorsal‐ventral axes in embryos of a variety of genotypes that include a null mutation in Psc. The phenotypes of embryos that are doubly mutant for a null allele of Psc and a mutation in a second Pc group gene show dramatic synergistic effects, but in their specifics they are dependent on the identify of the second Pc group gene. This is different from the relatively uniform phenotypes seen among double mutants that contained the allele Psc1, which has both gain and loss of function properties. The differences in the phenotypes of the doubly mutant embryos allow us to eliminate one class of molecular models to explain the dramatic synergism seen with mutations in this group of genes.
Mosaicism of tyrosinase‐locus transcription and chromatin structure in dark vs. light melanocyte clones of homozygous chinchilla‐mottled mice
Authors: Porter Susan , Larue Lionel , Mintz Beatrice 
Published: May 2005

AbstractThe chinchilla‐mottled (cm) mutation at the mouse tyrosinase‐encoding locus leads to a transversely striped pattern of dark‐ and light‐grey coat colors in homozygotes. The same basic pattern occurs in various other genotypes and has previously been found to represent the clonal developmental history of melanocytes. In a homozygote such as cm/cm, cis‐acting mechanisms would be expected to account for the color differences. To search for these mechanisms, the genomic structure of the mutation was examined and compared with the wild‐type, and its function was compared in cultured melanocyte clones of the respective colors. Evidence from restriction mapping indicated that the coding region of the mutant gene resembles that of the fully and uniformly pigmented wild‐type. However, the upstream sequences are rearranged in the mutation. The rearrangement begins 5 kb 5′ of the transcription initiation site and is estimated to encompass at least 30 kb of distal upstream sequence. At least two stable functional states of the cm gene were detectable: Light‐cell clones have low levels of tyrosinase‐specific transcription, reduced DNAase I sensitivity of tyrosinase chromatin, and no detectable hypersensitive sites near the gene; dark‐cell clones have higher (but subnormal) levels of transcription, greater sensitivity of chromatin to DNAase I, and a hypersensitive site in the promoter region. The changed relation between the structural gene and its upstream region may separate it from cis‐acting control elements, resulting in reduced and variable ability to achieve the appropriate chromatin configuration near the time of melanocyte determination; differences in expression among clonal initiator cells are then mitotically perpetuated. © 1992 Wiley‐Liss, Inc.