摘要:

AbstractA number of proteins have been identified as components of the secretory pathway ofSaccharomyces cerevisiae(SECgene products). However, very little is known about the expression of these components and their regulation at the transcriptional level. In this study yeast cells were exposed to conditions that changed the secretory activity of the cells. The conditions analysed include the different stages of the cell cycle, overexpression of secretory proteins, and block of secretion and endocytosis. The effect of these conditions on the transcriptional expression levels of a number ofSECgenes (SAR1,SEC1,SEC14,SEC17,SEC18,SEC23,SEC62,YPT1) was analysed. In summary, no major changes in transcriptional expression levels could be detected. From these results we conclude that the components of the secretory pathway are expressed constitutively and that no general regulation of transcription exists, that could adjust the expression level of theSECgenes to the secretory activity of the cells.

ISSN:0749-503X    

DOI:10.1002/yea.320111002

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractOverproduction of chimeric proteins containing the HMG2/1 peptide, which comprises the seven transmembrane domains ofSaccharomyces cerevisiae3‐hydroxy‐3‐methylglutaryl‐CoA reductase isozymes 1 and 2, has previously been observed to induce the proliferation of internal endoplasmic reticulum‐like membranes. In order to exploit this amplified membrane surface area for the accommodation of heterologous microsomal proteins, we fused sequences coding for human cytochrome P4501A1 (CYP1A1) to sequence encoding the HMG2/1 peptide and expressed the hybrid genes in yeast. The heterologous hybrid proteins were targeted into strongly proliferated membranes, as shown by electron microscopic and immunofluorescent analysis. Fusion proteins comprising the whole CYP1A1 polypeptide (HMG2/1‐CYP1A1) exhibited 7‐ethoxyresorufin‐O‐deethylase activity, whereas fusion proteins lacking the N‐terminal 56 amino acids of CYP1A1 (HMG2/1‐ΔCYP1A1) were inactive and appeared to be unable to incorporate protoheme. Similar amounts of heterologous protein were detected in cells expressingHMG2/1‐CYP1A1,HMG2/1‐ΔCYP1A1andCYP1A1, respectively. Replacement of the N‐terminal membrane anchor domain of human NADPH‐cytochrome P450 oxidoreductase by the HMG2/1 peptide also resulted in a functional fusion enzyme, which was able to interact with HMG2/1‐CYP1A1 and the yeast endogenous P450

ISSN:0749-503X    

DOI:10.1002/yea.320111003

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractWe have cloned a new gene,SCP160, fromSaccharomyces cerevisiae, the deduced amino acid sequence of which does not exhibit overall similarity to any known yeast protein. A weak resemblance between the C‐terminal part of the Scp160 protein and regulatory subunits of cAMP‐dependent protein kinases from eukaryotes as well as the pstB protein ofEscherichia coliwas observed. TheSCP160gene resides on the left arm of chromosome X and codes for a polypeptide of molecular weight around 160 kDa. By immunofluorescence microscopy the Scp160 protein appears to be localized to the nuclear envelope and to the endoplasmic reticulum (ER). However, no signal sequence or membrane‐spanning region exists, suggesting that the Scp160 protein is attached to the cytoplasmic surface of the ER–nuclear envelope membranes. Disruption of theSCP160gene is not lethal but results in cells of decreased viability, abnormal morphology and increased DNA content. This phenotype is not reversible by transformation with a plasmid carrying the wild‐type gene. Crosses ofSCP160deletion mutant strains among each other or with unrelated strains lead to irregular segregation of genetic markers. Taken together the data suggest that the Scp160 protein is required during cell division for faithful partitioning of the ER–nuclear envelope membranes which inS. cerevisiaeenclose the duplicated

ISSN:0749-503X    

DOI:10.1002/yea.320111004

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe structural gene of GTP‐cyclohydrolase, involved in riboflavin biosynthesis, was cloned from aPichia guilliermondiigenomic library. A 1855 bp genomic DNA fragment complementing the riboflavin auxotrophies of anEscherichia coli ribAmutant, defective in GTP‐cyclohydrolase II, and aP. guilliermondii rib1mutant was isolated and sequenced. An open reading frame with the potential to encode a protein of 344 amino acids with a predicted molecular mass of 38 711 Da was detected. TheP. guilliermondiienzyme shows a high degree of homology to GTP‐cyclohydrolases type II fromE. coliandBaccillus subtilisand to GTP‐cyclohydrolase fromSaccharomyces cerevisiae. Functional GTP‐cyclohydrolase fromP. guilliermondiimay consist of four identical subunits. The sequence of theRIB1gene ofP. guilliermondiiwas submitted to the EMBL sequence database and is accessible under Accession Numb

ISSN:0749-503X    

DOI:10.1002/yea.320111005

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effects of produced ethanol and specific growth rate on the lipid content and composition ofSaccharomyces cerevisiaeCBS 2806 were studied using anaerobic chemostat cultures. The cells adapted to increased concentrations of produced ethanol by increasing the proportion of ergosterol at the expense of lanosterol, by increasing the proportion of phosphatidylinositol at the expense of phosphatidylcholine, and by increasing the amount of C18:0fatty acids in total phospholipids at the expense of C16:0fatty acids. The produced ethanol had no effect on the phospholipid content nor on the proportion of unsaturated fatty acids in the phospholipids.The specific growth rate had no effect on the phospholipid content, the sterol composition, the phospholipid composition, the fatty acid composition of total phospholipids, or on the proportion of unsaturated fatty acids in the phospholipids ofS. cerevisiae. It was not possible to separate the effects of produced ethanol and growth rate on the ergosterol content of the chemostat‐grownS. cerevisiaecell

ISSN:0749-503X    

DOI:10.1002/yea.320111006

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe nucleotide sequence of a 12·5 kbp segment of the left arm of chromosome IV is described. Five open reading frames (ORFs) longer than 100 amino acids were detected, all of which are completely confined to the 12·5 kbp region. Two ORFs (D1271 and D1286) correspond to previously sequenced genes (PPH22andVMA1orTFP1, respectively). ORF D1298 shows the characteristics of α‐isopropylmalate and homocitrate synthase genes and is similar to thenifVgene ofAzotobacter vinelandii. Two more ORFs have no apparent homologue in the data libraries. Conversely, two smaller ORFs of 25 and 85 amino acids encoding the ribosomal protein YL41A and an ATPase inhibitor, respectively, were detected. Although a substantial part of the 12·5 kbp fragment apparently lacks protein‐coding characteristics, no other elements, such as tRNA genes or transposons, were found.The nucleotide sequence data reported in this paper will appear in the EMBL, GenBank and DDBJ Nucleotide Sequence Databases under the Accession Number

ISSN:0749-503X    

DOI:10.1002/yea.320111007

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 44 420 bp DNA fragment from chromosome XIV ofSaccharomyces cerevisiae. The sequence data revealed 23 open reading frames (ORFs) larger than 300 bp, covering 73·5% of the sequence. The ORFs N2418, N2441, N2474 and N2480 correspond to previously sequencedS. cerevisiaegenes coding respectively for the mitochondrial import proteinMas5, the nucleolar proteinNop2, the outer mitochondrial membrane porinPor1, the cytochromecoxidase polypeptide VA precursorCoxAand the yeast protein tyrosine phosphatase Msg5. Translation products of three other ORFs N2406, N2411 and N2430 exhibit similarity to previously knownS. cerevisiaeproteins: the ribosomal protein YL9A, the protein Nca3 involved in the mitochondrial expression of subunits 6 and 8 of the ATP synthase and actin; in addition N2505 presents strong similarity to an ORF of chromosome IX. The predicted protein products of ORFs N2417 and N2403 present similarities with domains from proteins of other organisms: theCandida maltosacycloheximide‐resistance protein, the human interleukin enhancer‐binding factor (ILF‐2). The 12 remaining ORFs show no significant similarity to known proteins. In addition, we have detected a DNA region very similar to the yeast transposon Ty 1–15 of which insertion has disrupted a tRNAAspgene. The sequence has been deposited in the GenBank database with the Accession Numbe

ISSN:0749-503X    

DOI:10.1002/yea.320111008

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe nucleotide sequence of a 29·425 kb fragment localized on the left arm of chromosome XV fromSaccharomyces cerevisiaehas been determined. The sequence contains 13 open reading frames (ORFs) of which four encode the known genesADH1,COQ3,MSH2andRCF4. Predictions are made concerning the functions of the unknown ORFs. Some of the ORFs contain sequences similar to expressed sequences tags (EST) found in the database made available by TIGR. In particular, the highly expressedADH1gene is represented in this database by no less than 20 EST sequences. Two ARS sequences and a putative functionalGCN4motif have also been detected. One ORF (O0953) containing nine putative transmembrane segments is similar to a hypothetical membrane protein ofArabidopsis thaliana. Characteristic features of the other ORFs include ATP/GTP binding sites, a fungal Zn(2)‐Cys(6) binuclear centre, an endoplasmic reticulum targeting sequence, a β‐transducin repeat signature and in two instances, good similarity to the prokaryotic lipoprotein signal peptide motif. The sequence has been deposited in the EMBL data library under Accession Number X

ISSN:0749-503X    

DOI:10.1002/yea.320111009

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractAn 8·2 kb DNA segment from the left arm ofSaccharomyces cerevisiaechromosome XIV (GenBank/EMBL accession number: X83226) encompasses four open reading frames (ORFs) longer than 100 residues. The ORF N0295 is highly similar to theAspergillus parasiticusandSchizosaccharomyces pombe nmt1gene products, which are involved in thiamine biosynthesis and are strongly repressed by thiamine. N0300 is 76% identical to YCR107w, a hypothetical protein of yeast chromosome III, and 55% identical to a ligninolytic aryl‐alcohol dehydrogenase from the white‐rot fungusPhanerochaete chrysosporium. In addition, this fragment encodes Rpd3, a pleiotropic transcription factor (Vidal and Gaber, 1991), and part of Pas8, a protein essential for the biogenesis of peroxisomes (Voorn‐Brouwer)et al., (1993). The sequence of the right flanking region has already been submitted to the EMBL data library under Accession Number Z46259 (Maftahiet al.,

ISSN:0749-503X    

DOI:10.1002/yea.320111010

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

ISSN:0749-503X    

DOI:10.1002/yea.320111011

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY