Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new gene, STE50, which plays an essential role in cell differentiation in Saccharomyces cerevisiae was detected and analysed. STE50 expression is not cell type-specific and its expression in MATa and MAT alpha cells is unaffected by pheromones. When present on a high copy number plasmid, STE50 causes supersensitivity to alpha-pheromone, and increases the level of alpha-pheromone-induced transcription of FUS1 in haploid a cells. Mutants bearing either of the two gene disruptions, ste50-1 or ste50-2, are sterile and have a modulated sensitivity to alpha-pheromone. The overexpression of STE4 (G beta) in wild-type cells elicits a constitutive growth arrest signal, however this phenotype is suppressed by a C-terminal truncation mutation in STE50 (ste50-2). In contrast, the constitutive activation of the pheromone response pathway caused by disruption of GPA1 (G alpha) is not suppressed in ste50-2 mutants. The ste50-2 mutation partially suppresses the desensitisation defect of the sst2-1 mutation, and the resulting ste50-2 sst2-1 mutants restore fertility. Our results indicate that the ste50-2 mutant may have a defect in adaptation (hyperadaptation), and suggest a possible interaction of STE50-2 with the G alpha subunit of the G protein.
Mol Gen Genet 1992 Dec
PMID:STE50, a novel gene required for activation of conjugation at an early step in mating in Saccharomyces cerevisiae. 149 45

In the yeast Saccharomyces cerevisiae, sporulation occurs in response to nutritional and genetic signals. The process is initiated when nutrient availability limits mitotic growth, but only in MATa/MAT alpha diploid cells. Under these conditions, the cells express an activator of meiosis (IME1), which is required for the expression of early sporulation-specific genes. We describe a new gene, IME4, whose activity is essential for IME1 transcript accumulation and sporulation. The IME4 transcript was induced in starved MATa/MAT alpha diploids but not in other cell types. In addition, excess IME4 promoted sporulation in mat-insufficient cells. Thus, IME4 appears to activate IME1 in response to cell type and nutritional signals. We have also explored the interactions between IME4 and two genes that are known to regulate IME1 expression. Normally, cells that lack complete MAT information cannot sporulate; when such strains lack RME1 activity or contain the semidominant RES1-1 mutation, however, they can express IME1 and sporulate to low levels. Our results show that mat-insufficient strains containing rme1::LEU2 or RES1-1 bypass mutations still retain MAT control of IME4 expression. Even though IME4 levels remained low, the rme1::LEU2 and RES1-1 mutations allowed IME1 accumulation, implying that these mutations do not require IME4 to exert their effects. In accord with this interpretation, the RES1-1 mutation allowed IME1 accumulation in MATa/MAT alpha strains that contain ime4::LEU2 alleles. These strains still sporulated poorly, suggesting that IME4 plays a role in sporulation in addition to promoting IME1 transcript accumulation. IME4 is located between ADE5 and LYS5 on chromosome VII.
Mol Cell Biol 1992 Mar
PMID:IME4, a gene that mediates MAT and nutritional control of meiosis in Saccharomyces cerevisiae. 154 90

The mating type gene MATA of the dimorphic yeast Yarrowia lipolytica was cloned. The strategy used was based on the presumed function of this gene in the induction of sporulation. A diploid strain homozygous for the mating type B was transformed with an integrative gene bank from an A wild-type strain. A sporulating transformant was isolated, which contained a plasmid with an 11.6 kb insert. This sequence was rescued from the chromosomal DNA of the transformant and deletion mapping was performed to localize the MAT insert. The MAT gene conferred both sporulating and non-mating phenotypes on a B/B diploid. A LEU2 sequence targeted to this locus segregated like a mating type-linked gene. The A strain did not contain silent copies of the MAT gene.
Mol Gen Genet 1992 Apr
PMID:Cloning of the mating-type gene MATA of the yeast Yarrowia lipolytica. 158 11

Complementary DNA clones representing transcripts selectively expressed in the non-dividing, infective (metacyclic) stage of Leishmania major promastigotes (MP) were identified by differential and subtractive screening. The majority of the selected clones hybridized on Northern blots to a set of transcripts highly expressed by MP, but to a much lower extent in proliferating and stationary-phase attenuated promastigotes. Stationary, but not log-phase cultures, of each of 5 L. major strains showing a potential for differentiation to metacyclics, expressed these transcripts (MAT-1; MP-associated transcripts). From sequence analysis of full-length cDNA clones corresponding to the predominating MAT-1 species, an open reading frame encoding a 139 aa polypeptide (15.4 kDa) was predicted and supported by immunoprecipitation by kala-azar sera of reticulocyte extract translation products using in vitro transcribed RNA. Although no significant primary sequence homology to database nucleic acid and protein sequences was found, the sequence displays similarities to the basic-zipper families of transcription regulatory proteins.
Mol Biochem Parasitol 1992 Jun
PMID:Genes selectively expressed in the infectious (metacyclic) stage of Leishmania major promastigotes encode a potential basic-zipper structural motif. 162 Jan 62

Two Saccharomyces cerevisiae strains containing integrated copies of the MAT alpha 1 gene fused to the PHO5 promoter have been obtained by transformation of a MAT alpha 1 mutant. The strains differ in length of 5'-uncoding region of the MAT alpha 1 in the integrated constructions. The mating activity and the ability of these strains to express the yeast MF alpha 1 gene and the hyman alpha-N-interferon gene under the control of MF alpha 1 promoter was shown to be regulated by the exogenous inorganic phosphate. The level of intracellular alpha-N-interferon synthesized in these strains was several fold higher as compared with the wild type alpha mating type strain. At the same time the observed increase in intracellular production is not accompanied by an increase in the level of secreted alpha-N-interferon. On the contrary, one of the strains had a two-fold reduction in the rate of secretion.
Mol Gen Mikrobiol Virusol 1991 Dec
PMID:[Preparation of Saccharomyces cerevisiae strains with regulated MFalpha1 promotor activity]. 178 39

Vegetatively grown Saccharomyces cerevisiae cells contain an activity that promotes a number of homologous pairing reactions. A major portion of this activity is due to strand exchange protein 1 (Sep1), which was originally purified as a 132,000-Mr species (R. Kolodner, D. H. Evans, and P. T. Morrison, Proc. Natl. Acad. Sci. USA 84:5560-5564, 1987). The gene encoding Sep1 was cloned, and analysis of the cloned gene revealed a 4,587-bp open reading frame capable of encoding a 175,000-Mr protein. The protein encoded by this open reading frame was overproduced and purified and had a relative molecular weight of approximately 160,000. The 160,000-Mr protein was at least as active in promoting homologous pairing as the original 132,000-Mr species, which has been shown to be a fragment of the intact 160,000-Mr Sep1 protein. The SEP1 gene mapped to chromosome VII within 20 kbp of RAD54. Three Tn10LUK insertion mutations in the SEP1 gene were characterized. sep1 mutants grew more slowly than wild-type cells, showed a two- to fivefold decrease in the rate of spontaneous mitotic recombination between his4 heteroalleles, and were delayed in their ability to return to growth after UV or gamma irradiation. Sporulation of sep1/sep1 diploids was defective, as indicated by both a 10- to 40-fold reduction in spore formation and reduced spore viability of approximately 50%. The majority of sep1/sep1 diploid cells arrested in meiosis after commitment to recombination but prior to the meiosis I cell division. Return-to-growth experiments showed that sep1/sep1 his4X/his4B diploids exhibited a five- to sixfold greater meiotic induction of His+ recombinants than did isogenic SEP1/SEP1 strains. sep1/sep1 mutants also showed an increased frequency of exchange between HIS4, LEU2, and MAT and a lack of positive interference between these markers compared with wild-type controls. The interaction between sep1, rad50, and spo13 mutations suggested that SEP1 acts in meiosis in a pathway that is parallel to the RAD50 pathway.
Mol Cell Biol 1991 May
PMID:Molecular and genetic analysis of the gene encoding the Saccharomyces cerevisiae strand exchange protein Sep1. 184 Jun 32

Saccharomyces cerevisiae strains carrying vps18 mutations are defective in the sorting and transport of vacuolar enzymes. The precursor forms of these proteins are missorted and secreted from the mutant cells. Most vps18 mutants are temperature sensitive for growth and are defective in vacuole biogenesis; no structure resembling a normal vacuole is seen. A plasmid complementing the temperature-sensitive growth defect of strains carrying the vps18-4 allele was isolated from a centromere-based yeast genomic library. Integrative mapping experiments indicated that the 26-kb insert in this plasmid was derived from the VPS18 locus. A 4-kb minimal complementing fragment contains a single long open reading frame predicted to encode a 918-amino-acid hydrophilic protein. Comparison of the VPS18 sequence with the PEP3 sequence reported in the accompanying paper (R. A. Preston, H. F. Manolson, K. Becherer, E. Weidenhammer, D. Kirkpatrick, R. Wright, and E. W. Jones, Mol. Cell. Biol. 11:5801-5812, 1991) shows that the two genes are identical. Disruption of the VPS18/PEP3 gene (vps18 delta 1::TRP1) is not lethal but results in the same vacuolar protein sorting and growth defects exhibited by the original temperature-sensitive vps18 alleles. In addition, vps18 delta 1::TRP1 MAT alpha strains exhibit a defect in the Kex2p-dependent processing of the secreted pheromone alpha-factor. This finding suggests that vps18 mutations alter the function of a late Golgi compartment which contains Kex2p and in which vacuolar proteins are thought to be sorted from proteins destined for the cell surface. The Vps18p sequence contains a cysteine-rich, zinc finger-like motif at the COOH terminus. A mutant in which the first cysteine of this motif was changed to serine results in a temperature-conditional carboxypeptidase Y sorting defect shortly after a shift to nonpermissive conditions. We identified a similar cysteine-rich motif near the COOH terminus of another Vps protein, the Vps11/Pep5/End1 protein. Preston et al. (Mol. Cell. Biol. 11:5801-5812, 1991) present evidence that the Vps18/Pep3 protein colocalizes with the Vps11/Pep5 protein to the cytosolic face of the vacuolar membrane. Together with the similar phenotypes exhibited by both vps11 and vps18 mutants, this finding suggests that they may function at a common step during vacuolar protein sorting and that the integrity of their zinc finger motifs may be required for this function.
Mol Cell Biol 1991 Dec
PMID:A putative zinc finger protein, Saccharomyces cerevisiae Vps18p, affects late Golgi functions required for vacuolar protein sorting and efficient alpha-factor prohormone maturation. 184 Jun 35

Saccharomyces cerevisiae has been used widely both as a model system for unraveling the biochemical, genetic, and molecular details of gene expression and the secretion process, and as a host for the production of heterologous proteins of biotechnological interest. The potential of starch as a renewable biological resource has stimulated research into amylolytic enzymes and the broadening of the substrate range of S. cerevisiae. The enzymatic hydrolysis of starch, consisting of linear (amylose) and branched glucose polymers (amylopectin), is catalyzed by alpha- and beta-amylases, glucoamylases, and debranching enzymes, e.g., pullulanases. Starch utilization in the yeast S. cerevisiae var. diastaticus depends on the expression of the three unlinked genes, STA1 (chr. IV), STA2 (chr. II), and STA3 (chr. XIV), each encoding one of the extracellular glycosylated glucoamylases isozymes GAI, GAII, or GAIII, respectively. The restriction endonuclease maps of STA1, STA2, and STA3 are identical. These genes are absent in S. cerevisiae, but a related gene, SGA1, encoding an intracellular, sporulation-specific glucoamylase (SGA), is present. SGA1 is homologous to the middle and 3' regions of the STA genes, but lacks a 5' sequence that encodes the domain for secretion of the extracellular glucoamylases. The STA genes are positively regulated by the presence of three GAM genes. In addition to positive regulation, the STA genes are regulated negatively at three levels. Whereas strains of S. diastaticus are capable of expressing the STA genes, most strains of S. cerevisiae contain STA10, whose presence represses the expression of the STA genes in an undefined manner. The STA genes are also repressed in diploid cells, presumably by the MATa/MAT alpha-encoded repressor. STA gene expression is reduced in liquid synthetic media, it is carbon catabolite repressed by glucose, and is inhibited in petite mutants.
Crit Rev Biochem Mol Biol 1991
PMID:The glucoamylase multigene family in Saccharomyces cerevisiae var. diastaticus: an overview. 187 99

We sequenced two alleles of the MATa locus of Saccharomyces cerevisiae that reduce homothallic switching and confer viability to HO rad52 strains. Both the MATa-stk (J. E. Haber, W. T. Savage, S. M. Raposa, B. Weiffenbach, and L. B. Rowe, Proc. Natl. Acad. Sci. USA 77:2824-2828, 1980) and MATa-survivor (R. E. Malone and D. Hyman, Curr. Genet. 7:439-447, 1983) alleles result from a T----A base change at position Z11 of the MAT locus. These strains also contain identical base substitutions at HMRa, so that the mutation is reintroduced when MAT alpha switches to MATa. Mating-type switching in a MATa-stk strain relative to a MATa Z11T strain is reduced at least 50-fold but can be increased by expression of HO from a galactose-inducible promoter. We confirmed by Southern analysis that the Z11A mutation reduced the efficiency of double-strand break formation compared with the Z11T variant; the reduction was more severe in MAT alpha than in MATa. In MAT alpha, the Z11A mutation also creates a mat alpha 1 (sterile) mutation that distinguishes switches of MATa-stk to either MAT alpha or mat alpha 1-stk. Pedigree analysis of cells induced to switch in G1 showed that MATa-stk switched frequently (23% of the time) to produce one mat alpha 1-stk and one MAT alpha progeny. This postswitching segregation suggests that Z11 was often present in heteroduplex DNA that was not mismatch repaired. When mismatch repair was prevented by deletion of the PMS1 gene, there was an increase in the proportion of mat alpha 1-stk/MAT alpha sectors (59%) and in pairs of switched cells that both retained the stk mutation (27%). We conclude that at least one strand of DNA only 4 bp from the HO cut site is not degraded in most of the gene conversion events that accompany MAT switching.
Mol Cell Biol 1991 Oct
PMID:Heteroduplex formation and mismatch repair of the "stuck" mutation during mating-type switching in Saccharomyces cerevisiae. 192 52

Copies of the mating-type genes are present at three loci on chromosome III of the yeast Saccharomyces cerevisiae. The genes at the MAT locus are transcribed, whereas the identical genes at the silent loci, HML and HMR, are not transcribed. Several genes, including the four SIR genes, and two sites, HMR-E and HMR-I, are required for repression of transcription at the HMR locus. Three elements have been implicated in the function of the HMR-E silencer: a binding site for the RAP1 protein, a binding site for the ABF1 protein, and an 11-bp consensus sequence common to nearly all autonomously replicating sequence (ARS) elements (putative origins of DNA replication). RAP1 and ABF1 binding sites of different sequence than those found at HMR-E were joined with an 11-bp ARS consensus sequence to form a synthetic silencer. The synthetic silencer was able to repress transcription of the HMRa1 gene, confirming that binding sites for RAP1 and ABF1 and the 11-bp ARS consensus sequence were the functional components of the silencer in vivo. Mutations in the ABF1 binding site or in the ARS consensus sequence of the synthetic silencer caused nearly complete derepression of transcription at HMR. The ARS consensus sequence mutation also eliminated the ARS activity of the synthetic silencer. These data suggested that replication initiation at the HMR-E silencer was required for establishment of the repressed state at the HMR locus.
Mol Cell Biol 1991 Nov
PMID:A synthetic silencer mediates SIR-dependent functions in Saccharomyces cerevisiae. 192 68


1 2 3 4 5 6 7 8 9 10 Next >>