摘要:

AbstractTheCDC33gene ofSaccharomyces cerevisiaebelongs to the class II ‘START’ genes. Its product is required for the initiation of a new cell division cycle (Hartwell, 1974). Many results suggest that the cAMP signalling pathway is one of the major controlling elements of ‘START’. Components of this pathway are encoded by class II ‘START’ genes. The aim of the present study is to determine whether or not theCDC33gene interferes with the cAMP signalling pathway. We report here the molecular cloning of theCDC33gene by complementation of thecdc33‒1thermosensitive mutant. The identity of the cloned gene is confirmed by site‐specific reintegration and segregation analysis. This gene is transcribed into a 900‐nucleotides mRNA and appears to be relatively abundant in the cell. We also show that theCDC33gene product is essential for sporulation.cdc33‒1mutant cells are able to enter into the resting state. The cAMP intracellular pool is not modified when thecdc33‒1mutant is shifted to the restrictive temperature. Thecdc33‒1mutation is not suppressed by other known elements of the cAMP cascade. All these results suggest that theCDC33‘START’ gene does not interfere with the cAMP signalling pathway w

ISSN:0749-503X    

DOI:10.1002/yea.320050203

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractRespiratory‐deficient mutants (rho−cells) ofSaccharomyces cerevisiaeproduced about 10 times as much human(h‐) lysozyme as did wild‐type strains (rho+cells) when theGAL10promoter was used in an expression plasmid with the h‐lysozyme gene. Introduction of intact mitochondria into therho−cells resulted in a significant decrease in the production of h‐lysozyme, indicating that therho−mutation increased the expression of the h‐lysozyme gene. The copy number of the expression plasmid was not responsible for the increased expression. The level of h‐lysozyme mRNA in therho−cells was also much higher than that in therho+cells especially at the stationary phase. The increased expression of the h‐lysozyme gene was also observed when a glyceraldehyde‐3‐phosphate dehydrogenase gene promoter and thePHO5promoter were used in the expression plasmid. Therho−mutation also increased the expression of thePHO5gene under the control of theHIS5promoter in a plasmid and theACT1gene in the yeast chromosome, but did not increase the expression of the ribosomal RNA gene. In contrast to therho−mutants,petmutants did not show higher gene expression

ISSN:0749-503X    

DOI:10.1002/yea.320050204

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe analysis of five independent isolates ofKluyveromyces lactisshows that CBS 2359, CBS 683 and CBS 4574 could grow in the presence of mitochondrial inhibitors (antimycin A, oligomycin or erythromycin) and that CBS 2360 and CBS 141 were unable to grow in the presence of drugs. The resistant growth was observed only on glucose and not on other fermentable carbon sources (galactose, lactose).The phenotype ‘growth on glucose in the presence of mitochondrial inhibitors’ was called Rag+. This phenotype was found to be controlled by two unlinked nuclear genes:RAG1andRAG2. Either of their recessive alleles,rag1andrag2, led to the Rag−phenotype (i.e. the failure of growth on glucose in the presence of antimitochondrial drugs).Rag−strains represent the case in which fermentative growth becomes absolutely dependent on the functioning of the normal respirator

ISSN:0749-503X    

DOI:10.1002/yea.320050205

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe secreted glycoproteins ofPichia pastoriscontain more than 35% of theirN‐linked oligosaccharides as structures smaller than Man14GlcNAc2(Man = mannose; GlcNAc =N‐acetylglucosamine). On heterologous invertase produced inP. pastoris, approximately 85% of the oligosaccharides are in the size range Man8–14GlcNAc2. The structures appear to contain α‐linked mannose. In addition, one‐third of the structures contain net negative charge and can be radio‐labelledin vivowith32P. The largest oligosaccharides isolated fromP. pastorisare significantly shorter than the hypermannosylated structures typical ofS. cerevisiae, indicating that the factors which influence the processing ofN‐linked oligosaccharides inP. pastorisare different from those which influence processing inS. cerevisiae.The smallerN‐linked oligosaccharides synthesized byP. pastorisresemble high‐mannose oligosaccharides synthesized by animal cells, and this finding increases the utility ofP. pastorisas a host for the production of heterolo

ISSN:0749-503X    

DOI:10.1002/yea.320050206

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractA detailed characterization of themak 1–3mutation ofSaccharomyces cerevisiaehas been made possible by modifying its genetic background. Themak1–3mutation, which confers temperature sensitivity for growth, was originally identified as one of fourmak1mutations (Wickner and Leibowitz, 1976).Mak1–1,1–2and1–4mutants are deficient in DNA topoisomerase I activity and thus have been renamed ‘top1’ (Thrashet al., 1984). Studies presented here show that the map position ofMAK1–3on chromosome XVI distinguishes it fromTOP1which maps on chromosome XV (Wickner and Leibowitz, 1976). An investigation ofin vivomacromolecular synthesis in themak1–3mutant shows that it is deficient in DNA replication at the restrictive temperature. Experiments in which DNA synthesis was measured in synchronized cell populations indicate that themak1–3mutant is deficient in the initiation step of DNA synthesis. Furthermore, crude extracts from themak1–3mutant cells support temperature‐sensitivein vitroDNA synthesis on yeast chromosomal DNA replication origin containing plasmid pARS1, suggesting that theMAK1gene product is directly required forin vitroDNA replication. The conclusion thatmak1–3is a newly identified DNA replication mutation is based on the observations that it (1) complements all DNA synthesis mutants examined, (2) maps to a previously undetected chromosomal location and (3) has a distinct terminal morphology. In light of these distinctions and of the rolemak1–3plays in DNA replication,

ISSN:0749-503X    

DOI:10.1002/yea.320050207

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractG1 cells of the diploid yeastSaccharomyces cerevisiaeare known to be capable of a slow repair of DNA double‐strand breaks (DSB) during holding the cells in a non‐nutrient medium (Luchniket al., 1977; Frankenberg‐Schwageret al., 1980). In the present paper,S. cerevisiaecells γ‐irradiated in the G1 phase of the cell cycle are shown to be capable of fast repair of DNA DSB; this process is completed within 30‒40 min, of holding the cells in water at 28°C. For this reason, the kinetics of DNA DSB repair during holding the cells in a non‐nutrient medium are biphasic, i.e., the first ‘fast’ phase is completed within 30‒40 min, whereas the second, ‘slow’ phase is completed within 48 h. Mututionsrad51,rad52,rad54andrad55inhibit the fast repair of DNA DSB, whereas mutationsrad50,rad53andrad57do not significantly influence this process.It has been shown that the observed fast and slow repair of DNA DSB in the G1 diploid cells ofS. cerevisiaeare separate pathways of

ISSN:0749-503X    

DOI:10.1002/yea.320050208

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320050202

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY