Suppression of sorbitol dependence in a strain bearing a mutation in the SRB1/PSA1/VIG9 gene encoding GDP-mannose pyrophosphorylase by PDE2 overexpression suggests a role for the Ras/cAMP signal-transduction pathway in the control of yeast cell-wall biogenesis.
Complementation studies and allele replacement in Saccharomyces cerevisiae revealed that PSA1/VIG9, an essential gene that encodes GDP-mannose pyrophosphorylase, is the wild-type SRB1 gene. Cloning and sequencing of the srb1-1 allele showed that it determines a single amino acid change from glycine to aspartic acid at residue 276 (srb1(D276)). Genetic evidence is presented showing that at least one further mutation is required for the sorbitol dependence of srb1(D276). A previously reported complementing gene, which this study has now identified as PDE2, is a multi-copy suppressor of sorbitol dependence and is not, as was previously suggested, the SRB1 gene. srb and pde2 mutants share a number of phenotypes, including lysis upon hypotonic shock and enhanced transformability. These data are consistent with the idea that the Ras/cAMP pathway might modulate cell-wall construction.
Tomlin
Gregory C
GC
School of Biological Sciences, 2.205 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK1.
Hamilton
Grant E
GE
Department of Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD, UK2.
Gardner
David C J
DCJ
Department of Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD, UK2.
Walmsley
Richard M
RM
Department of Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD, UK2.
Stateva
Lubomira I
LI
Department of Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD, UK2.
Oliver
Stephen G
SG
School of Biological Sciences, 2.205 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK1.
D000595:Amino Acid Sequence; D002473:Cell Wall / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D016153:Genes, Suppressor; D008969:Molecular Sequence Data; D009154:Mutation; D009713:Nucleotidyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009997:Osmotic Pressure; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015398:Signal Transduction; D013012:Sorbitol / Q000378:metabolism*; D014170:Transformation, Genetic; D018631:ras Proteins / Q000378:metabolism*
D005656:Fungal Proteins; D013012:Sorbitol; D000242:Cyclic AMP; D009713:Nucleotidyltransferases; C026917:mannose 1-phosphate guanylyltransferase; D018631:ras Proteins