ISSN:0749-503X    

DOI:10.1002/yea.320070702

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe promoter and enhancer of the rRNA gene ofSaccharomyces cerevisiaehave been studied using a nuclease S1 protection assay to detect transcripts of an rRNA minigene in transformed yeast. Analysis of 5′ deletion mutants showed that DNA between − 163 bp and − 155 bp was important for promoter activity and that some DNA between − 155 bp and − 145 bp was essential. The importance of DNA far upstream from the initiation site was confirmed by showing that minigene expression was much reduced by linker scanner mutations clustered around − 148 bp, − 133 bp and − 100 bp, and was abolished by mutations clustered around − 118 bp. The enhancer for rRNA biosynthesis increased transcription from all of the five mutated promoters that were tested. The magnitude of the enhancer effects on weakly active promoters was two‐ to three‐fold less than on the wild‐type promoter. Expression of a minor transcript in a 5′ deletion to − 10 bp was substantially reduced by a mutation which altered two base pairs in the core sequence of the promoter

ISSN:0749-503X    

DOI:10.1002/yea.320070703

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320070704

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTheDAL3gene has been sequenced and found to encode a 195 amino acid protein with a molecular weight of 21 727. The four carboxy‐terminal amino acids ofDAL3product (Cys‐Ile‐Ile‐Ile) are homologous to those (CAAX) previously shown to be the primary structural signal for post‐translational farnesylation of yeast RAS protein and mating factor. This modification is reported to be responsible for membrane localization of proteins containing it. The upstream region ofDAL3contains six copies of a sequence that is homologous to the positively actingDAL UASNTRreported to be required for transcriptional activation of theDAL5andDAL7genes. Missing from theDAL3upstream region were any sequences related to those shown to be required for aDAL7response to inducer, theUISelement. This correlates with the previous report thatDAL3expression is independent of the allantoin pathwa

ISSN:0749-503X    

DOI:10.1002/yea.320070705

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractHsp70 proteins have been highly conserved throughout evolution. As a first step in a structure–function analysis of hsp70, we constructed and analysed the consequences of mutations in a portion of theSSA1gene, a member of theSaccharomyces cerevisiaeHSP70 multigene family, that encodes a nearly invariant region near the amino terminus. Analysis of strains expressingSSA1proteins with alterations at positions 8, 11 and 15 showed that these conserved residues within this region are critical for normal functioning of the protein.SSA1protein containing either of two changes at position 15 was able to slightly complement the inviability of anssa1ssa2ssa4strain, but was inactive in other complementation assays. The other mutant proteins tested were unable to complement any tested phenotype. Effective interallelic complementation of several phenotypes was observed when a mutant protein substituted at position 8 was expressed in the same cell with either of two proteins carrying substitutions at position 15, suggesting that hsp70 acts as a multimer. Evidence from previous studies suggests that hsp70 proteins engage in ATP‐driven cycles of binding and release from peptides. The ability of the mutant proteins to bind ATP and a peptide was tested. The Ssa 1p carrying a substitution at position 8, which inhibits growth of cells carrying wild‐typeSSAproteins, showed a defect in release from a peptide relative to wild type. Two mutations, one each at position 8 and 15, resulted in accumulation of phosphorylated isoforms which may be a normal, transient hsp70 interme

ISSN:0749-503X    

DOI:10.1002/yea.320070706

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractMannoproteins were isolated fromSaccharomyces cerevisiae mnn9mutant cell walls by laminarinase digestion and purified by affinity and anion‐exchange chromatography. The purified mannoprotein fraction contained three predominant proteins with molecular masses of 300 kDa, 220 kDa and 160 kDa. These compounds were absent in an SDS extrct of cell walls or in a hot‐citrate extract ofmnn9cells.The carbohydrate part of the purified mannoproteins consisted of (N‐acetyl)glucosamine, mannose and glucose in a molar ratio of 1:53:4.O‐Glycosidically linked chains, containing 70% of the mannose, were released by mild β‐elimination.N‐Glycosidically linked chains, representing 80% of the (N‐acetyl)glucosamine and 20% of the mannose, were released by peptideN‐glycosidase F (PNGase F) digestion. Complete degradation of protein by alkaline hydrolysis released besides theN‐ andO‐glycosidically linked chains, another type of carbohydrate chain containing the residual (N‐acetyl)glucosamine, mannose and most of the glucose in a molar ratio of 1:17:18. Glucose was β‐glycosidically linked.The results indicate that β‐glucose is linked to PNGase F‐resistantN‐linked chains present on cell wall mannoproteins. We propose that these chains are responsible for the linkage between mannoprot

ISSN:0749-503X    

DOI:10.1002/yea.320070707

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractIn yeast, nutrient starvation leads to entry into stationary phase. Mutants that do not respond properly to starvation conditons have been isolated inSaccharomyces cerevisiae. Among them thervs161mutant (RVS forReducedViability uponStarvation) is sensitive to carbon, nitrogen and sulphur starvation. When these nutrients are depleted in the medium, mutant cells show cellular viability loss with morphological changes. The mutationrvs161‐1is very pleiotropic, and besides the defects in stationary phase entry, the mutant strain presents other alterations: sensitivity to high salt concentrations, hypersensitivity to amino acid analogs, no growth on lactate or acetate medium. The addition of salts or amino acid analogs leads to the same morphological defects observed in starved cells, suggesting that the gene could be implicated mainly in the control of cellular viability. The geneRVS161was cloned; it codes for a 30,252 daltons protein. No homology was detected with the proteins contained in the databases. Moreover, Southern analysis revealed the presence of other sequences homologous to theRVS161gene in the yeast genom

ISSN:0749-503X    

DOI:10.1002/yea.320070708

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe fission yeast,Schizosaccharomyces pombe, expresses one of two alternative mating types. They are specified by one of two determinants (MorP) present at themat1locus. In addition, silent copies ofMandPare present on the same chromosome. In the present work we demonstrate that the difference between the active and the silent stage of thePdeterminant is controlled by four repressive elements that are located at the silent locus. There are two elements to the left and two to the right of the mating type cassette. Both elements to the left and either one of the two elements to the right are required for an effective blockage of transcription. When they are combined, the four elements define a highly efficient silencer functionally similar to theHMREandHMLEandHMLIsilencers inSaccharomyces cerevisiae. In addition, the DNA surrounding the silentPlocus confers symmetric partitioning in mitosis toSchizosaccharomyces pombe arsplasmids.

ISSN:0749-503X    

DOI:10.1002/yea.320070709

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320070710

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractWe report the sequence of a 7·5 kb region lying between theCRY1andMATloci of chromosome III fromSaccharomyces cerevisiae. This region lies in the overlap between two major contigs used for the generation of the complete nucleotide sequence of this chromosome. Comparison of this sequence with those reported previously for this overlap [Thierryet al. (1990)Yeast6, 521; Jiaet al. (1991)Yeast7, 413] reveals 38 nucleotide differences, 45% of which generate changes in the amino acid sequences of the four genes in this region (YCR591,YCR592,YCR521andYCR522). These differences appear to reflect true sequence polymorphisms between the two yeast strains used to generate the clones used in the sequencing project. Three of the four genes in this region display weak homologies to proteins in the PIR database. Some properties ofYCR521are analogous to those of ribosomal protein genes. However, the functions of all four genes remain obscure

ISSN:0749-503X    

DOI:10.1002/yea.320070711

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY