摘要:

AbstractPlasma membrane was isolated from the salt‐tolerant yeastCandida versatilisand the ATPase in plasma membrane was characterized. The ATPase was a typical H+‐ATPase with similar properties to theSaccharomyces cerevisiaeandZygosaccharomyces rouxiienzymes. It was reacted with antibody (IgG) raised againstS. cerevisiaeplasma membrane H+‐ATPase. The ATPase activity was not changed by adding NaCl and KCl to the assay solutions, but was increased by NH 4+, especially by ammonium sulfate.In vivostimulation of ATPase activity was observed by the addition of NaCl into the culture medium, as observed inZ. rouxii. Noin vivoactivation of H+‐ATPase by glucose metabolism was observed inC. versatiliscells and the activity was independent of the growth phase, likeZ. rouxiiand unlikeS. cerevi

ISSN:0749-503X    

DOI:10.1002/yea.320090302

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractIn addition to exoglucanases (EXGs) I and II, old cultures ofSaccharomyces cerevisiaesecreted into the culture medium a new immunologically‐related material that exhibited exoglucanase activity. The new exoglucanase (EXGII1/2) was purified from stationary‐phase cultures. It turned out to be a glycoprotein whose protein portion was identical to that of the other two isoenzymes in terms of ionic properties, size, amino acid composition and NH2‐terminal sequence (25 residues). Disruption of the structural gene encoding EXGs I and II resulted in a strain unable to secrete all three isoenzymes. EXGII1/2was indistinguishable in terms of molecular weight from the single intermediate detected during the deglycosylation (mediated by endo H) of EXGII by sodium dodecyl sulphate–polyacrylamide gel electrophoresis. Thus, the new isoenzyme contains only one of the two slightly elongated mannan inner cores present in enzyme II. Two intermediates were, however, detected when the deglycosylation of EXGII was monitored by ion‐exchange chromatography (high‐pressure liquid chromatography). Site‐directed mutagenesis indicated that the major intermediate, which eluted at about the same position as enzyme II1/2, corresponded to protein molecules carrying the oligosaccharide attached to the Asn of the second sequon, whereas the minor one carried the oligosaccharide in the first potential glycosylation site. Several lines of evidence indicate that EXGII1/2is a biosynthetic product resulting from an imbalance between the rate of protein synthesis and the glycosylation capabilities of the glycosylat

ISSN:0749-503X    

DOI:10.1002/yea.320090303

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractIn the yeastSaccharomyces cerevisiae, the nucleus undergoes dramatic shape changes during mitosis and mating. We have studied nuclear envelope dynamics during the processes of mitosis and conjugation using nuclear pore complexes as a marker for the nuclear envelope in wild‐type cells and several cell‐division‐cycle (cdc) mutants.Three monoclonal antibodies are described that recognize nuclear pore complex‐related antigens inS. cerevisiae. One of these antibodies, RL1, has been extensively characterized by Gerace and colleagues and recognizes nuclear pore complexes in mammalian and amphibian cells. By indirect immunofluorescence of yeast cells, all three antibodies yield a discontinuous nuclear rim stain. All three react with multiple nuclear‐enriched proteins in immunoblots, including the nucleoporin protein encoded by theNSP1gene.When the antibodies were used in immunofluorescence experiments on mating cells, the nuclear pore complex staining pattern proved to be a sensitive indicator of nuclear fusion. Nuclei with closely apposed spindle pole bodies and unfused nuclear envelopes could be readily distinguished. Marked shape changes were observed in nuclei during fusion and segregation of the diploid nucleus into the zygotic bud.Incdc14andcdc15mutants that arrest late in mitosis, the elongated nuclear envelope extension that stretches between daughter nuclei during telophase was preserved. In cytokinesis‐defective mutants (cdc3, cdc10, cdc11andcdc12), the elongated nuclear envelope was usually resolved into two daughter nuclei in the absence of cytokinesis. These results indicate that nuclear envelope division is mechanistically distinguishable from chromosome segregation, nucleolar segregation and

ISSN:0749-503X    

DOI:10.1002/yea.320090304

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractK1killer strains ofSaccharomyces cerevisiaesecrete a polypeptide toxin to which they are themselves immune. The α and β components of toxin comprise residues 45–147 and 234–316 of the 316‐residue K1preprotoxin. The intervening 86‐residue segment is called γ. A 26‐residue signal peptide is removed on entry into the endoplasmic reticulum. The Kex2 protease excises the toxin components from the 290‐residue glycosylated protoxin in a late Golgi compartment. Expression of a cDNA copy of the preprotoxin gene confers the complete K1killer phenotype on sensitive cells. We now show that expression of immunity requires that α component and the N‐terminal 31 residues of γ. An additional C‐terminal extension, either eight residues of γ or three of four unrelated peptides, is also required. Expression of preprotoxin terminating at the α C‐terminus, or lacking the γ N‐terminal half of γ causes profound but reversible growth inhibition. Inhibition is suppressed incisby the same 31 residues of γ required for immunity to exocellular toxin intrans, but not by the presence of β. Both immunity and growth inhibition are alleviated by insertions in α that inactivate toxin. Inhibition is not suppressed bykex2, chc1orkre1mutations, by growth at higher pH or temperature, or by normal K1immunity. Inhibition, therefore, probably does not involve processing of the α toxin component at its N‐terminus or release from the cell and binding to glucan receptors. Some insertion and substitution mutations in γ severely reduce toxin secretion without affecting immunity. They are presumed to affect protoxin folding in the endoplasmic retic

ISSN:0749-503X    

DOI:10.1002/yea.320090305

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractSelection of mutations, based on the suppression ofrvs161Δ defects, was performed. Ten mutants were obtained, ranged amongst four complementation groups, namedSUR1, SUR2, SUR3andSUR4. Allsurmutations also suppress a mutation in another gene,RVS167, indicating that all six genes are involved in the same biological pathway. Thesurmutant cells have abnormal morphologies in stationary phase, i.e. dumbbell‐like insur1, sur2orsur3strains and multibudded insur4strains. Several phenotypic characteristics of the physiological suppressors as well as thervs161Δ strain itself led us to analyse the phospholipid composition of the mutants. The assays show an overall decrease of the phospholipid amounts and modifications in the relative contents of some phospholipid classes insurmutant ce

ISSN:0749-503X    

DOI:10.1002/yea.320090306

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractWe report here the DNA sequence of a segment of chromosome XI ofSaccharomyces cerevisiaeextending over 7·8 kb. The segment contains four long open reading frames,YKL150, YKL153, YKL155andYKL156, YKL155corresponds to theCAP1gene.YKL153contains an intron and shows an extremely biased codon usage suggestive of a highly expressed protein.YKL156is a homolog toUOG‐1, an open reading frame associated with the cDNA clone of the mammalian growth/differentiation factor 1.YKL150reveals common motifs to both the RNA polymerase II elongation factor ofDrosophila melanogasterand to the yeastPPR2gene produ

ISSN:0749-503X    

DOI:10.1002/yea.320090307

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe nucleotide sequence of a fragment of 4867 base pairs ofSaccharomyces cerevisiaechromosome II has been determined. The sequence contains three complete open reading frames. In addition to the already known geneRPB5, coding for a subunit shared by all three DNA directed RNA polymerases, two new open reading frames could be identified. YBR12.03 codes for a protein of 183 amino acids with homology to one of the proteins of theBacillus subtilisriboflavin biosynthesis operon (RibG). Deletion mutants of YBR12.03 can germinate but stop growing after five to seven cell divisions on YPD. Supplementation with high concentrations of riboflavin does promote growth. YBR12.05 codes for a protein of 386 amino acids with homology toSTI1, a stress‐inducible protein ofS. cerevisiae. Deletion mutants of YBR12.05 are not viabl

ISSN:0749-503X    

DOI:10.1002/yea.320090308

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractTheSaccharomyces cerevisiaeRNA polymerase II subunit geneRPB7was isolated and sequenced.RPB7is a single copy gene whose sequence predicts a 19,000 Dalton protein of 171 amino acids. RPB7 is known to dissociate from RNA polymerase II as an RPB4/RPB7 subcomplexin vitro. RPB7 also appears to interact with RNA polymerase II in a manner dependent upon RPB4, since RNA polymerase II purified from cells lacking RPB4 also lacks RPB7. Previous results have demonstrated that deletion of theRPB4results in slow growth and cold‐ and temperature‐sensitivity. In contrast, deletion of theRPB7gene revealed that it is essential for cell growth and viability. Loss of both theRPB4and theRPB7genes causes lethality. These results suggest that RPB7 contributes to the function of RNA polymerase II in the absence of RPB4 either in a manner independent of its association with the enzyme or by directly binding to the enzyme in a manner independent of its association with R

ISSN:0749-503X    

DOI:10.1002/yea.320090309

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractWe have cloned and sequenced aSaccharomyces cerevisiaegene coding for a protein with significant similarities to the mitochondrial carrier family. The gene we termedYMC1(yeast mitochondrial carrier) is located on chromosome XVI, closely downstream ofARO7encoding chorismate mutase.

ISSN:0749-503X    

DOI:10.1002/yea.320090310

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320090311

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY