A novel role for the mating type (MAT) locus in the maintenance of cell wall integrity in Saccharomyces cerevisiae

In homothallic cells of Saccharomyces cerevisiae, a or alpha mating type information at the mating type locus (MAT) is replaced by the transposition of the opposite mating type allele from HML alpha or HMRa. The rad52-1 mutation, which reduces mitotic and abolishes meiotic recombination, also affects homothallic switching (Malone and Esposito, Proc. Natl. Acad. Sci. U.S.A. 77:503-507, 1980). We have found that both HO rad52 MATa and HO rad52 MAT alpha cells die. This lethality is suppressed by mutations that substantially reduce but do not eliminate homothallic conversions. These mutations map at or near the MAT locus (MAT alpha inc, MATa-inc, MATa stk1) or are unlinked to MAT (HO-1 and swi1). These results suggest that the switching event itself is involved in the lethality. With the exception of swi1, HO rad52 strains carrying one of the above mutations cannot convert mating type at all. MAT alpha rad52 HO swi1 strains apparently can switch MAT alpha to MATa. However, when we analyzed these a maters, we found that few, if any, of them were bona fide MATa cells. These a-like cells were instead either deleted for part of chromosome III distal to and including MAT or had lost the entire third chromosome. Approximately 30% of the time, an a-like cell could be repaired to a normal MATa genotype if the cell was mated to a RAD52 MAT alpha-inc strain. The effects of rad52 were also studied in mata/MAT alpha-inc rad52/rad52 ho/HO diploids. When this diploid attempted to switch mata to MATa, an unstable broken chromosome was generated in nearly every cell. These studies suggest that homothallic switching involves the formation of a double-stranded deoxyribonucleic acid break or a structure which is labile in rad52 cells and results in a broken chromosome. We propose that the production of a double-stranded deoxyribonucleic acid break is the lethal event in rad52 HO cells.

Download Full-text

Functional domains of SIR4, a gene required for position effect regulation in Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.7.12.4441-4452.1987 ◽

1987 ◽

Vol 7 (12) ◽

pp. 4441-4452

Author(s):

M Marshall ◽

D Mahoney ◽

A Rose ◽

J B Hicks ◽

J R Broach

Keyword(s):

Saccharomyces Cerevisiae ◽

Mating Type ◽

Position Effect ◽

Protein Activity ◽

Multicomponent Complex ◽

Mating Type Genes ◽

Chromosome Iii ◽

Covalently Linked ◽

High Level ◽

Mat Locus

The product of the Saccharomyces cerevisiae SIR4 gene, in conjunction with at least three other gene products, prevents expression of mating-type genes resident at loci at either end of chromosome III, but not of the same genes resident at the MAT locus in the middle of the chromosome. To address the mechanism of this novel position effect regulation, we have conducted a structural and genetic analysis of the SIR4 gene. We have determined the nucleotide sequence of the gene and found that it encodes a lysine-rich, serine-rich protein of 152 kilodaltons. Expression of the carboxy half of the protein complements a chromosomal nonsense mutation of sir4 but not a complete deletion of the gene. These results suggest that SIR4 protein activity resides in two portions of the molecule, but that these domains need not be covalently linked to execute their biological function. We also found that high-level expression of the carboxy domain of the protein yields dominant derepression of the silent loci. This anti-Sir activity can be reversed by increased expression of the SIR3 gene, whose product is normally also required for maintaining repression of the silent loci. These results are consistent with the hypothesis that SIR3 and SIR4 proteins physically associate to form a multicomponent complex required for repression of the silent mating-type loci.

Download Full-text

Homothallic switching of Saccharomyces cerevisiae mating type genes by using a donor containing a large internal deletion

Molecular and Cellular Biology ◽

10.1128/mcb.5.8.2154-2158.1985 ◽

1985 ◽

Vol 5 (8) ◽

pp. 2154-2158

Author(s):

B Weiffenbach ◽

J E Haber

Keyword(s):

Saccharomyces Cerevisiae ◽

Gene Conversion ◽

Mating Type ◽

Gene Conversion Event ◽

Conversion Event ◽

Base Pair Deletion ◽

Mating Type Genes ◽

Type Gene ◽

Mat Locus ◽

Donor Locus

Homothallic switching of the mating type genes of Saccharomyces cerevisiae occurs by a gene conversion event, replacing sequences at the expressed MAT locus with a DNA segment copied from one of two unexpressed loci, HML or HMR. The transposed Ya or Y alpha sequences are flanked by homologous regions that are believed to be essential for switching. We examined the transposition of a mating type gene (hmr alpha 1-delta 6) which contains a 150-base-pair deletion spanning the site where the HO endonuclease generates a double-stranded break in MAT that initiates the gene conversion event. Despite the fact that the ends of the cut MAT region no longer share homology with the donor hmr alpha 1-delta 6, switching of MATa or MAT alpha to mat alpha 1-delta 6 was efficient. However, there was a marked increase in the number of aberrant events, especially the formation of haploid-inviable fusions between MAT and the hmr alpha 1-delta 6 donor locus.

Download Full-text

Tolerant industrial yeast Saccharomyces cerevisiae posses a more robust cell wall integrity signaling pathway against 2-furaldehyde and 5-(hydroxymethyl)-2-furaldehyde

Journal of Biotechnology ◽

10.1016/j.jbiotec.2018.04.002 ◽

2018 ◽

Vol 276-277 ◽

pp. 15-24 ◽

Cited By ~ 5

Author(s):

Z. Lewis Liu ◽

Xu Wang ◽

Scott A. Weber

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Wall ◽

Signaling Pathway ◽

Cell Wall Integrity ◽

Industrial Yeast ◽

Yeast Saccharomyces Cerevisiae

Download Full-text

Zinc oxide nanoparticles induce toxicity by affecting cell wall integrity pathway, mitochondrial function and lipid homeostasis in Saccharomyces cerevisiae

Chemosphere ◽

10.1016/j.chemosphere.2018.09.028 ◽

2018 ◽

Vol 213 ◽

pp. 65-75 ◽

Cited By ~ 16

Author(s):

Piyoosh Kumar Babele ◽

Pilendra Kumar Thakre ◽

Ramesh Kumawat ◽

Raghuvir Singh Tomar

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Wall ◽

Zinc Oxide ◽

Mitochondrial Function ◽

Zinc Oxide Nanoparticles ◽

Cell Wall Integrity ◽

Lipid Homeostasis ◽

Oxide Nanoparticles ◽

Cell Wall Integrity Pathway

Download Full-text

Mpt5p, a Stress Tolerance- and Lifespan-Promoting PUF Protein in Saccharomyces cerevisiae, Acts Upstream of the Cell Wall Integrity Pathway

Eukaryotic Cell ◽

10.1128/ec.00188-06 ◽

2006 ◽

Vol 6 (2) ◽

pp. 262-270 ◽

Cited By ~ 30

Author(s):

Mark S. Stewart ◽

Sue Ann Krause ◽

Josephine McGhie ◽

Joseph V. Gray

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Wall ◽

Life Span ◽

Stress Tolerance ◽

Synthetic Medium ◽

Cell Wall Integrity ◽

Puf Proteins ◽

Downstream Target ◽

Cell Wall Integrity Pathway ◽

Puf Protein

ABSTRACT Pumilio family (PUF) proteins affect specific genes by binding to, and inhibiting the translation or stability of, their transcripts. The PUF domain is required and sufficient for this function. One Saccharomyces cerevisiae PUF protein, Mpt5p (also called Puf5p or Uth4p), promotes stress tolerance and replicative life span (the maximum number of doublings a mother cell can undergo before entering into senescence) by an unknown mechanism thought to partly overlap with, but to be independent of, the cell wall integrity (CWI) pathway. Here, we found that mpt5Δ mutants also display a short chronological life span (the time cells stay alive in saturated cultures in synthetic medium), a defect that is suppressed by activation of CWI signaling. We found that Mpt5p is an upstream activator of the CWI pathway: mpt5Δ mutants display the appropriate phenotypes and genetic interactions, display low basal activity of the pathway, and are defective in activation of the pathway upon thermal stress. A set of mRNAs that specifically bind to Mpt5p was recently reported. One such putative target, LRG1, encodes a GTPase-activating protein for Rho1p that directly links Mpt5p to CWI signaling: Lrg1p inhibits CWI signaling, LRG1 mRNA contains a consensus Mpt5p-binding site in its putative 3′ untranslated region, loss of Lrg1p suppresses the temperature sensitivity and CWI signaling defects of mpt5Δ mutants, and LRG1 mRNA abundance is inhibited by Mpt5p. We conclude that Mpt5p is required for normal replicative and chronological life spans and that the CWI pathway is a key and direct downstream target of this PUF protein.

Download Full-text

Cell fusion in yeast is negatively regulated by components of the cell wall integrity pathway

Molecular Biology of the Cell ◽

10.1091/mbc.e18-04-0236 ◽

2019 ◽

Vol 30 (4) ◽

pp. 441-452 ◽

Cited By ~ 2

Author(s):

Allison E. Hall ◽

Mark D. Rose

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Death ◽

Cell Wall ◽

Yeast Cell ◽

Cell Fusion ◽

Cell Walls ◽

Cell Wall Integrity ◽

Fusion Genes ◽

Cell Wall Degradation ◽

Cell Wall Integrity Pathway

During mating, Saccharomyces cerevisiae cells must degrade the intervening cell wall to allow fusion of the partners. Because improper timing or location of cell wall degradation would cause lysis, the initiation of cell fusion must be highly regulated. Here, we find that yeast cell fusion is negatively regulated by components of the cell wall integrity (CWI) pathway. Loss of the cell wall sensor, MID2, specifically causes “mating-induced death” after pheromone exposure. Mating-induced death is suppressed by mutations in cell fusion genes ( FUS1, FUS2, RVS161, CDC42), implying that mid2Δ cells die from premature fusion without a partner. Consistent with premature fusion, mid2Δ shmoos had thinner cell walls and lysed at the shmoo tip. Normally, Cdc42p colocalizes with Fus2p to form a focus only when mating cells are in contact (prezygotes) and colocalization is required for cell fusion. However, Cdc42p was aberrantly colocalized with Fus2p to form a focus in mid2Δ shmoos. A hyperactive allele of the CWI kinase Pkc1p ( PKC1*) caused decreased cell fusion and Cdc42p localization in prezygotes. In shmoos, PKC1* increased Cdc42p localization; however, it was not colocalized with Fus2p or associated with cell death. We conclude that Mid2p and Pkc1p negatively regulate cell fusion via Cdc42p and Fus2p.

Download Full-text

In Saccharomyces cerevisiae, impaired PRPP synthesis is accompanied by valproate and Li+ sensitivity

Biochemical Society Transactions ◽

10.1042/bst0331154 ◽

2005 ◽

Vol 33 (5) ◽

pp. 1154-1157 ◽

Cited By ~ 5

Author(s):

S. Vavassori ◽

K. Wang ◽

L.M. Schweizer ◽

M. Schweizer

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Wall ◽

Nitrogen Metabolism ◽

Phospholipid Metabolism ◽

Cell Wall Integrity ◽

Yeast Genome ◽

Carbon And Nitrogen ◽

Yeast Physiology ◽

Cellular Biochemistry ◽

Carbon And Nitrogen Metabolism

The biosynthetic intermediate PRPP (phosphoribosylpyrophosphate) has a central role in cellular biochemistry since it links carbon and nitrogen metabolism. Its importance may be reflected in the fact that, in the Saccharomyces cerevisiae (yeast) genome, there are five unlinked genes, PRS1–PRS5, each of which is theoretically capable of encoding the enzyme synthesizing PRPP. Interference with the complement of PRS genes in S. cerevisiae has far-reaching consequences for yeast physiology and has uncovered unexpected metabolic links including cell wall integrity and phospholipid metabolism.

Download Full-text