摘要:

AbstractThe appearance dynamics of spontaneous revertants in adenine‐ or leucine‐auxotrophic haploidSaccharomyces cerevisiaestrains has been studied using mathematical simulation methods. In the case of adenine auxotrophs an increase in the number of revertants with decreasing metabolite content is found to result mainly from increasing the rate of intragenic suppressor mutations. In the case of leucine auxotrophs revertants result from increasing the appearance of mutants formed at similar rates under different cultivation conditions. In the latter case the appearance of mutant colonies increases with decreasing size of colonies of the initial auxotrophic cells. The last can simulate so‐called adaptive mutagenesis. The heterogeneity of revertants appearing in different time periods is desc

ISSN:0749-503X    

DOI:10.1002/yea.320110802

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe expression of a hybrid gene encoding an α‐factor prepro leader peptide‐miniproinsulin (MPI) fusion [MPI is the same as the LysArg human insulin precursor described by Thimet al.(1986)] was tested in a series of isogenic yeast strains to investigate the influence of some genetic and physiological factors on heterologous production in yeast. We found that: (i) anMFα1gene disruption in haploid cells, as well asMFα1gene product expression in diploid cells, do not affect the MPI secretion level; (ii) under conditions of exogenous leucine availability, MPI production is hindered by leucine auxotrophy (aleu2mutation); (iii)rho−mutations increase the per‐cell MPI yield approximately three‐fold; (iv) the MPI yield is apparently dependent on the pH of the culture medium: the higher the external pH, the larger the per‐

ISSN:0749-503X    

DOI:10.1002/yea.320110803

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThree glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) genes fromKluyveromyces marxianuswere identified and characterized. The coding region of two of them (GAP2andGAP3) is very similar (99·6% homology). The other gene (GAP1) is only 86% homologous toGAP2orGAP3and is responsible for the expression of Gap1p. This protein is extremely homologous to theK. marxianuscell wall protein p37, presumably involved in flocculation. However, no leader sequence could be detected in this gene. The identification of the three genes was possible with the use of polymerase chain reaction–single‐strand conformation polymorphism (PCRSSCP), as it permits us to overcome the difficulties caused by the high homology amongst the genes. Expression of the GAPDH genes under different carbon sources (glucose or ethanol) was assessed either by Northern blot or reverse transcription–PCRSSCP analysis, revealing that genesGAP1andGAP2, but notGAP3, are transcribed. The results also indicate that the transcription of the gene encoding the cell wall protein p37 (Gap1p) is not dependent on the carbon source, in contrast with the expression of the geneGAP2, which is affected in cells growing in a glucose

ISSN:0749-503X    

DOI:10.1002/yea.320110804

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractIn the yeastSaccharomyces cerevisiaethree dominant flocculation genes,FLO1, FLO5andFLO8have been described. Until now only theFLO1gene, which is located at chromosome I, has been cloned and sequenced.FLO5andFLO8were previously localized at chromosomes I and VIII respectively (Vezinhet, F., Blondin, B. and Barre, P. (1991). Mapping of theFLO5gene ofSaccharomyces cerevisiaeby transfer of a chromosome during cytoduction.Biotechnol. Lett.13, 47–52; Yamashita, I. and Fukui, S. (1983). Mating signals control expression of both starch fermentation genes and a novel flocculation geneFLO8in the yeastSaccharomyces. Agric. Biol. Chem.47, 2889–2896). This was not in agreement with our results. Here, we report the location ofFLO5andFLO8on chromosomes VIII and I respectively.By induced chromosome loss and genetic mapping, theFLO5gene was localized at the right end of chromosome VIII approximately 34 cM centromere distal ofPET3. This is part of the region that is present both at chromosome I and chromosome VIII. The location ofFLO5in this area of chromosome VIII made it necessary to re‐evaluate the localization ofFLO8, which was previously thought to occur in this region. Both genetic and physical mapping showed thatFLO8is allelic toFLO1. Hence, there are only two known dominant flocculation genes,FLO1andFLO5.Analysis of the nucleotide sequence of chromosome VIII of a non‐flocculent strain revealed an open reading frame encoding a putative protein that is approximately 96% identical to the Flo1 protein.This suggests that both dominant flocculation genes encode similar, cell wall‐associated, proteins with the same function in the flocculation

ISSN:0749-503X    

DOI:10.1002/yea.320110805

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSaccharomyces cerevisiaepossesses a single essential gene (GLC7) encoding protein phosphatase 1 (PP1). Elevated expression of this gene from theGAL1promoter is highly detrimental to the cell, causing a growth defect and aberrant bud morphology, which leads to cells exhibiting long, extended buds. By comparison, expression ofGLC7from the weakerMET3promoter was without significant effect on either growth or morphology. However, repression ofGLC7expression from theMET3promoter in cells where theMET3‐GLC7fusion was the sole source of PP1 resulted in a mitotic delay. Such cultures showed a massive decrease in the rate of proliferation in conjunction with a significant increase in the proportion of large, budded cells. 4′,6‐diamidino‐2‐phenylindole dihydrochloride (DAPI) staining and anti‐tubulin immunofluorescence analysis of these cells revealed that many were blocked in mitosis, with a short spindle and DAPI‐stained material stretched between the mother and daughter cell within the bud neck. These results support a role for PP1 in the completion of mitosis in

ISSN:0749-503X    

DOI:10.1002/yea.320110806

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSequence analysis of the newly definedSSU81gene revealed an adjacent open reading frame (ORF) encoding a protein whose deduced amino acid sequence is identical to that of ribosomal protein L17. The DNA sequence of this region is different from that of theRPL17Agene and therefore represents a duplicate gene encoding L17. We have designated this geneRPL17B. TheRPL17Bcoding region is split by an intron that occurs in the same position (codons 14/15) as the intron inRPL17A. TheRPL17Bpromoter region includes two TATA boxes, a canonical UASRPGmotif, and several pyrimidine‐rich tracts.RPL17Bwas mapped by CHEF and lambda clone grid hybridization blots to the right arm of chromosome V, linked to theTRP2andRAD51genes. A partial ORF was identified adjacent toRPL17BandSSU81that is homologous to an ORF (designated A509) physically linked toRPL17A. This observation, and the identical position of the introns within theRPL17genes, suggest that oneRPL17locus arose by duplication and translocation of the other. The complete 3·8 kbp DNA sequence encompassingRPL17Bhas been entered in the GenBank data library under Accession Number U156

ISSN:0749-503X    

DOI:10.1002/yea.320110807

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe report the sequence of a 7941 bp DNA fragment from the left arm of chromosome VII ofSaccharomyces cerevisiaewhich contains four open reading frames (ORFs) of greater than 100 amino acid residues. ORF biC834 shows 100% bp identity with the recently identified multicopy suppressor gene of thepop2mutation (MPT5); its deduced protein product carries an eight‐repeat domain region, homologous to that found in the hypothetical regulatory YGL023 protein ofS. cerevisiaeand the Pumilio protein ofDrosophila. ORF biE560 protein exhibits patterns typical of serine/threonine protein kinases, with which it shares high degrees of homology. The complete nucleotide sequence was submitted to the EMBL Data Library under Accession Number X8369

ISSN:0749-503X    

DOI:10.1002/yea.320110808

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have sequenced a 42,500 bp stretch located on chromosome X ofSaccharomyces cerevisiaebetween the genesMET3andCDC8. This stretch contains 24 open reading frames (ORFs) of at least 100 amino acids. Ten of these correspond to previously published sequences, whereas of the 14 remaining ORFs, only one, GTD892, has significant similarity to proteins from yeast or other organisms. It may belong to the family of ubiquitin–protein ligases and be involved in the ubiquitin‐dependent proteolytic pathway. In addition, three tRNA genes were recognized, two of which had not been hitherto localized. The sequence has been deposited in the Genome Sequence Data Base under Accession Number L36

ISSN:0749-503X    

DOI:10.1002/yea.320110809

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe polymorphic extracellular glucoamylase‐encoding genesSTA1(chr. IV),STA2(chr. II) andSTA3(chr. XIV), fromSaccharomyces cerevisiaevar.diastaticusprobably evolved by genomic rearrangement of DNA regions (S1, S2andSGA1) present inS. cerevisiae, and subsequent translocation to unlinked regions of chromosomal regions.S1, encoding a homologue to the threonine/serine‐rich domain ofSTAglucoamylases (GAI‐III), mapped to the right arm of chromosome IX.S2, encoding the hydrophobic leader peptide of GAI‐III, was also mapped on the right arm of chromosome IX, next toS1, close toDAL81. TheSGA1sporulation‐specific, intracellular glucoamylase‐encoding gene is located on the left arm of chromosome IX, 32 kb prox

ISSN:0749-503X    

DOI:10.1002/yea.320110810

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSSU71 (TFG1)is an essential nuclear gene encoding the largest subunit of the yeast general transcription factor TFIIF. TheSSU71gene was physically mapped to the right arm of chromosome VII, physically linked toQCR9, by hybridization of the cloned gene to CHEF and lambda clone grid blots. This assignment was confirmed by genetic mapping. A search of the nucleotide sequence databases revealed thatSSU71is immediately adjacent to theTYS1gene, which encodes tRNATyrsynthetase.TYS1was reported previously to lie on chromosome XV based on sequence overlap with the adjacentUBR1gene. The mapping data reported here established thatTYS1andUBR1do not lie on chromosome XV; rather theSSU71‐TYS1‐UBR1gene cluster lies on the right arm of chromosome VII, physically linked toQCR9and genetically linked toade3ands

ISSN:0749-503X    

DOI:10.1002/yea.320110811

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY