Saccharomyces cerevisiae: Sorbitol-dependent fragile mutants

Venkov, Pencho; Hadjiolov, A.A.; Battaner, E.; Schlessinger, David

doi:10.1016/0006-291x(74)90646-9

Cited by 68 publications

(28 citation statements)

References 6 publications

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“…It was expected that some of these mutants would be altered in cell wall composition and at least some of them would be affected in (1-3)3-D-glucan synthesis. This approach was tried previously in S. cerevisiae (33); however, having a spherical shape before lysis was not adopted as a condition in the selection protocol. The mutants obtained in that study seemed to be affected in the membrane rather than in the cell wall (14).…”

Section: Discussionmentioning

confidence: 99%

Isolation and characterization of Schizosaccharomyces pombe mutants defective in cell wall (1-3)beta-D-glucan

et al. 1991

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Schizosaccharomyces pombe thermosensitive mutants requiring the presence of an osmotic stabilizer to survive and grow at a nonpermissive temperature were isolated. The mutants were genetically and biochemically characterized. In all of them, the phenotype segregated in Mendelian fashion as a single gene which coded for a recessive character. Fourteen loci were defined by complementation analysis. Studies of cell wall composition showed a reduction in the amount of cell wall ,I-glucan in three strains (JCR1, JCR5, and JCR10) when growing at 37°C. Galactomannan was diminished in two others. Strains JCR1 and JCR5, with mutant alleles cwgl-l and cwg2-1, respectively, were further studied. The cwgl locus was mapped on the right arm of chromosome III, 18.06 centimorgans (cM) to the left of the ade5 marker; cwg2 was located on the left arm of chromosome I, 34.6 cM away from the aroS marker. (1-3)0-D-Glucan synthase activities from cwgl-l and cwg2-1 mutant strains grown at 37°C were diminished, as measured in vitro, compared with the wild-type strain; however, Km values and activation by GTP were similar to the wild-type values. Mutant synthases behaved like the wild-type enzyme in terms of thermostability. Analyses of round shape, lytic behavior, and low (1-3)0-D-glucan synthase activity in cultures derived from ascospores of the same tetrad showed cosegregation of all these characters. Detergent dissociation of (1-3)01-D-glucan synthase into soluble and particulate fractions and subsequent reconstitution demonstrated that the cwgl-1 mutant was affected in the particulate fraction of the enzymatic activity while cwg2-1 was affected in the soluble component. The antifungal agents Papulacandin B and Aculeacin A had similar effects on the enzymatic activities of the wild type and the cwg2-1 mutant strain, whereas the cwgl-1 mutant, when growing at 37°C, had a more inhibitor-resistant (1-3)0-D-glucan synthase. It is concluded that the cwgl+ and cwg2+ genes are related to (1-3)0I-D-glucan biosynthesis.

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Section: Discussionmentioning

confidence: 99%

Isolation and characterization of Schizosaccharomyces pombe mutants defective in cell wall (1-3)beta-D-glucan

et al. 1991

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“…The Ras/cAMP pathway has been further implicated in the maintenance of cell wall integrity by the fact that overexpression of PDE2 suppresses a number of cell wall defects that result from the srb1-1 mutation (a mutant allele of PSA1 encoding mannose-1-phosphate guanyltransferase; Refs. 82,84).Given the pleiotropic roles of the high-affinity cAMP-dependent PDE in S. cerevisiae, we decided to characterize the differences in the global pattern of gene expression between wild-type and pde2 mutant strains. We have used microarray technology to determine patterns of gene expression, resulting from a constitutive activation of the Ras/cAMP pathway, upon deletion of PDE2 in FY23, a strain isogenic to S288C.…”

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Transcriptome profiling of aSaccharomyces cerevisiaemutant with a constitutively activated Ras/cAMP pathway

Jones

Petty

Hoyle

et al. 2003

Physiological Genomics

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Often changes in gene expression levels have been considered significant only when above/below some arbitrarily chosen threshold. We investigated the effect of applying a purely statistical approach to microarray analysis and demonstrated that small changes in gene expression have biological significance. Whole genome microarray analysis of a pde2⌬ mutant, constructed in the Saccharomyces cerevisiae reference strain FY23, revealed altered expression of ϳ11% of protein encoding genes. The mutant, characterized by constitutive activation of the Ras/cAMP pathway, has increased sensitivity to stress, reduced ability to assimilate nonfermentable carbon sources, and some cell wall integrity defects. Applying the Munich Information Centre for Protein Sequences (MIPS) functional categories revealed increased expression of genes related to ribosome biogenesis and downregulation of genes in the cell rescue, defense, cell death and aging category, suggesting a decreased response to stress conditions. A reduced level of gene expression in the unfolded protein response pathway (UPR) was observed. Cell wall genes whose expression was affected by this mutation were also identified. Several of the cAMP-responsive orphan genes, upon further investigation, revealed cell wall functions; others had previously unidentified phenotypes assigned to them. This investigation provides a statistical global transcriptome analysis of the cellular response to constitutive activation of the Ras/cAMP pathway. constitutive activation of PKA by PDE2 deletion; Ras/cAMP pathway; cell wall integrity THE RAS/CAMP PATHWAY is a highly conserved signal transduction pathway operating via the second messenger, cAMP (6). In Saccharomyces cerevisiae, it controls cell-cycle progression, cell growth and proliferation (3, 81), reprogramming of transcription at the diauxic transition (8), mating (1), pseudohyphal morphogenesis (27, 55), metabolism (9), and stress responses. The synthesis of cAMP is catalyzed by adenylate cyclase (40), which is regulated by Ras proteins (18,24,80), the G protein ␣-subunit homolog, Gpa2 (48), and the adenylate-cyclase-associated protein, Cap1p (23,25). The only known biochemical role of cAMP is to activate protein kinase A (PKA) (12,78,79). High activity of PKA in yeast leads to low levels of the storage carbohydrates trehalose and glycogen, low stress resistance due to reduced expression of STRE ("stress response element")-controlled genes, aberrant G 0 arrest, poor growth on nonfermentable and weakly fermentable carbon sources, and failure of sporulation in diploid cells. Low activity yields de-repression of STRE-controlled genes leading to high stress resistance, constitutive expression of heat-shock genes, and sporulation of diploid cells in rich media (for reviews, see Refs. 10,64,[74][75][76]. Two trans-acting factors (Msn2p and Msn4p), negatively regulated by PKA, have been shown to be involved in STRE-mediated gene expression (47,67).Intracellular levels of cAMP, and hence the state of the Ras/cAMP pathway, are also contr...

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“…In contrast, the rest of the cell cycle after START, including the completion of bud development to produce an independent daughter cell, is relatively unaffected by overall biosynthetic status (16 (28,31). Segregants harboring the rsfl-J mutation were generated by successive backcrosses to the wild-type strain GR2 (17).…”

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The RSF1 gene regulates septum formation in Saccharomyces cerevisiae

1991

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Septum formation in the mitotic cell cycle of the budding yeast Saccharomyces cerevisiae occurs by conversion of the chitin ring, laid down at bud formation, into the primary septum. We show here that under certain conditions this septation is dependent on the newly identified RSFI gene. However, cells harboring the rsfl-I mutation accumulated in a postcytokinesis state, with delayed conversion of the chitin-rich annulus into the primary septum. This rsfl-1-mediated inhibition of septum formation only occurred under conditions of biosynthetic stress and was correlated with biosynthetically mediated inhibition of the cell-cycle regulatory step START. The RSF1 gene is distinct from the CHS2 chitin synthase gene that is responsible for septation, and thus RSF1 most likely encodes a regulator of chitin synthesis. We hypothesize that RSFI activity facilitates septum formation during times of biosynthetic stress, to allow efficient septation even under these conditions.Cell proliferation by the yeast Saccharomyces cerevisiae occurs through bud formation. Several morphological events in bud development have been well characterized. Bud development begins with a localized evagination of the cell wall and underlying plasma membrane. At this time (12) a ring of chitin is laid down in the cell wall at the site of bud emergence, the area that becomes the neck of the bud (3). Final resolution of the bud into an independent cell entails formation of a chitin-rich primary septum between the mother cell and the new daughter cell (the former bud). During septum formation the enzyme chitin synthase 2 synthesizes chitin and deposits it in an orderly fashion (23,26) to form a central plate that fills in the original chitin ring laid down at bud emergence (reviewed in reference 4). Selective hydrolysis by chitinase (7) then leads to cell separation, which may be followed by repair of the septum by another enzyme, chitin synthase 1 (5).Bud development is coordinated with other events in the cell cycle. The final stages of bud development depend on the performance of nuclear division, the yeast equivalent of mitosis; cells blocked at or before nuclear division do not form the septum (6). Similarly, the beginning of bud development depends on performance of START, the central regulatory step in the cell cycle; cells blocked in the performance of START do not initiate bud formation (10).The performance of START, and indirectly therefore the development of the bud, is responsive to the biosynthetic status of the cell (24, 32). In contrast, the rest of the cell cycle after START, including the completion of bud development to produce an independent daughter cell, is relatively unaffected by overall biosynthetic status (16 (14).Growth conditions. Cells were grown at 23°C in YNB minimal medium (16) containing glucose (2%) and supplemented with ammonium sulfate and auxotrophic requirements. Starvation was imposed by transfer of cells by centrifugation to medium lacking either a nitrogen source or histidine. The rsfl-J mutation was identified...

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Saccharomyces cerevisiae: Sorbitol-dependent fragile mutants

Cited by 68 publications

References 6 publications

Isolation and characterization of Schizosaccharomyces pombe mutants defective in cell wall (1-3)beta-D-glucan

Isolation and characterization of Schizosaccharomyces pombe mutants defective in cell wall (1-3)beta-D-glucan

Transcriptome profiling of aSaccharomyces cerevisiaemutant with a constitutively activated Ras/cAMP pathway

The RSF1 gene regulates septum formation in Saccharomyces cerevisiae

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