摘要:

AbstractProper maintenance of translational reading frame by ribosomes is essential for cell growth and viability. In the last 10 years it has been shown that a number of viruses induce ribosomes to shift reading frame in order to regulate the expression of gene products having enzymatic functions. Studies on ribosomal frameshifting in viruses of yeast have been particularly enlightening. The roles of viral mRNA sequences and secondary structures have been elucidated and a picture of how these interact with host chromosomal gene products is beginning to emerge. The efficiency of ribosomal frameshifting is important for viral particle assembly, and has identified ribosomal frameshifting as a potential target for antiviral agents. The availability of mutants of host chromosomal gene products involved in maintaining the efficiency of ribosomal frameshifting bodes well for the use of yeast in future studies of ribosomal frameshifting.

ISSN:0749-503X    

DOI:10.1002/yea.320111202

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this study we show that the previously describeduvs112(uvs12) mutation blocks one of the steps of the excision repair pathway. The properties of this mutation permit the assignment of theUVS112gene to theRAD3epistasis group. It was established that theuvs112mutation caused a 2·5‐fold reduction in the number of recombinants produced by conversion and also significantly increased the frequency of mitotic crossing‐over in interplasmid recombination. Tetrad analysis placed theUVS112gene on the left arm of chromosome IX, approximately 20 cM fromHIS5. The analysis of mitotic recombination revealed thatUVS112lies betweenHIS6andHIS5, and is an allele of theRAD25

ISSN:0749-503X    

DOI:10.1002/yea.320111203

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractExpression of the peroxisome‐deficient (Per−) phenotype bypermutants ofHansenula polymorphais shown to be dependent on specific environmental conditions. Analysis of our collection of constitutive and conditionalpermutants showed that, irrespective of the carbon source used, the mutants invariably lacked functional peroxisomes when ammonium sulphate was used as a nitrogen source. However, in two temperature‐sensitive (ts) mutants,per13‐6tsandper14‐11ts, peroxisomes were present at the restrictive temperature when cells were grown on organic nitrogen sources which are known to induce peroxisomes in wild‐type cells, namelyD‐alanine (for both mutants) or methylamine (forper14‐11ts). These organelles displayed normal wild‐type properties with respect to morphology, mode of development and protein composition.However, under these conditions not all the peroxisomal matrix proteins synthesized were correctly located inside peroxisomes. Detailed biochemical and (immuno) cytochemical analyses indicated that during growth of cells on methanol in the presence of eitherD‐alanine or methylamine, a minor portion of these proteins (predominantly alcohol oxidase, dihydroxyacetone synthase and catalase) still resided in the cytosol. This residual cytosolic activity may explain the observation that the functional restoration of the two ts mutants is not complete under these conditions, as is reflected by the retarded growth of the cells in batch c

ISSN:0749-503X    

DOI:10.1002/yea.320111204

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have identified a gene,GSG1(generalsporulationgene 1), required for sporulation inSaccharomyces cerevisiae. Diploids homozygous for a disruption ofGSG1fail to sporulate. The gene has an open reading frame of 2094 bp, encoding a polypeptide with an expected size of 77 kDa.GSG1is expressed mitotically in bothaand α haploids, and both mitotically and meiotically in diploids. The message level ofGSG1increases approximately two‐fold after 4–6 h of sporulation.gsg1mutants enter pre‐meiotic DNA synthesis later than wild‐type diploids. Mutant diploids are not rescued byspo13. These results suggest thatGSG1has a role late in meiosis following DNA replication. The sequence reported here has the GenBank Accession Numbe

ISSN:0749-503X    

DOI:10.1002/yea.320111205

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractStudies on the dynamics of growth of single eukaryotic cells and their relationships with cell cycle regulations are generally carried out following cell synchronization procedures or, on a relatively low number of cells, by time‐lapse studies. Establishment of both time‐lapse studies and synchronous cell populations usually requires elaborate experimental efforts and is prone to perturb the physiological state of the cell.In this paper we use a new flow cytometric approach which allows, in asynchronous growingSaccharomyces cerevisiaepopulations, tagging of both the cell age and the cell protein content of a cohort of daughter cells at the different cell cycle set points. Since the cell protein content is a good estimation of the cell size, it is possible to follow the kinetics of the cell size increase during cell cycle progression. The experimental findings obtained indicate an exponential increase of the cell size during growth, that the daughter and the parent subpopulations grow with the same specific growth rate, that the average cell size increase rate of each individual cell is almost identical to the specific growth rate of the overall population and provide the opportunity to estimate the cell cycle length for the daughter cell population as well as the identification of the complex structure of asynchronously growing yeast populati

ISSN:0749-503X    

DOI:10.1002/yea.320111206

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractBy complementation of a mutant resistant to N‐methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG) we have identified thegcs1gene, encoding a putative γ‐glutamylcysteine synthetase. The gene is possibly interrupted by two introns and has 49% identical and 80% similar amino acids compared with the homologous protein from rat. In comparison with theSaccharomyces cerevisiaehomologue it possesses 41% identical and 74% similar amino acids. Thegsc1sequence appears in the EMBL database under Accession

ISSN:0749-503X    

DOI:10.1002/yea.320111207

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have determined the complete nucleotide sequence of a 24·3 kb segment from chromosome X carried by the cosmid pEJ103. The sequence encodes five complete open reading frames (ORFs), none of which correspond to previously described genes; however, four of these ORFs display interesting similarities with sequences present in the databanks. The sequence also contains a tandem insertion of a Ty1 element. An investigation of the Ty1 polymorphism in other strains has revealed that the original insertion occurred within an ORF. Finally, the structure of the Ty1 repeat suggests a mechanism by which it may have been generated. The sequence has been deposited in the EMBL data library under the Accession Number X87297 for the complete sequence and X87298 for the δty1 versio

ISSN:0749-503X    

DOI:10.1002/yea.320111208

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe report the sequence of an 11·1 kb fragment located on the left arm of chromosome VII ofSaccharomyces cerevisiae. By sequence analysis we have detected six open reading frames (ORFs) longer than 300 bp, which cover 87% of the entire sequence. ORF G1645 is 100% identical to theKEM1gene, also identified asDST2, XRN1, SEP1andRAR5, while G1648 is 100% identical to theNSP49orNUP49gene. ORF G1642 shares some identity with a hypothetical protein ofCaenorhabditis elegans, while the other four ORFs show no significant homology to known proteins. The sequence has been submitted to the EMBL data library under Accession Number X84705

ISSN:0749-503X    

DOI:10.1002/yea.320111209

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractA 43,481 bp fragment from the left arm of chromosome XIV ofSaccharomyces cerevisiaewas sequenced. A gene for tRNApheand 23 non‐overlapping open reading frames (ORFs) were identified, seven of which correspond to known yeast genes:MFA2, MEP2, CAP/SRV2, NAM9, FKB1/FPR1/RBP1, MOM22andCPT1. One ORF may correspond to the yet unindentified yeast adenosine deaminase gene. Among the 15 other ORFs, four exhibit known signatures, which include a protein tyrosine phosphatase, a cytoskeleton‐associated protein and two ATP‐binding proteins, four have similarities with putative proteins of yeast or proteins from other organisms and seven exibit no significant similarity with amino acid sequences described in data banks. One ORF is identical to yeast expressed sequence tags (EST) and therefore corresponds to an expressed gene. Six ORFs present similarities to human dbESTs, thus identifying motifs conserved during evolution. Nine ORFs are putative transmembrane proteins. In addition, one overlapping and three antisense ORFs, which are not likely to be functional, were detected. The sequence has been deposited in the EMBL data bank under Accession Number Z

ISSN:0749-503X    

DOI:10.1002/yea.320111210

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320111211

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY