ras1 and pat1 alleles interact to quantitatively and qualitatively alter conjugation in fission yeast.
To identify novel components of ras1+ signalling in Schizosaccharomyces pombe, extragenic suppressors of the mating defect of ras1 effector mutants were isolated. A novel allele of pat1, pat1-e1, was isolated that increases the mating of ras1-D43E mutants to near wild-type levels but does not suppress the mating defect of ras1-I41M, ras1-Y37F, or ras1-Y45I mutants. This allele-specific suppression is not a characteristic of all pat1 alleles since pat1-3 and pat1-114 partially and equally suppress ras1-D43E and ras1-I41M mutants. Analysis of mating cultures showed that ras1-D43E and pat1-e1 interact to qualitatively alter the mating response. While pat1-e1 ras1-D43E cells were delayed in agglutination, cell-cycle delay, and mat1-Pm transcription, they induce mat1-Mc at the same time and mate more rapidly than other mating cultures. These results suggest that pheromone signalling, but not nutritional signalling, is delayed in pat1-e1 ras1-D43E cells. We hypothesize that this delay causes an elevated pheromone response and thus suppression of the mating defect of the ras1-D43E mutant by pat1-e1.
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655 Light Hall, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA.
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D000483:Alleles; D002455:Cell Division / Q000235:genetics; D003227:Conjugation, Genetic / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005456:Fluorescent Dyes / Q000378:metabolism; D005656:Fungal Proteins; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005800:Genes, Fungal / Q000235:genetics; D007211:Indoles / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010675:Pheromones / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D013170:Spores / Q000235:genetics; D013489:Suppression, Genetic / Q000235:genetics; D018631:ras Proteins / Q000235:genetics*
D004268:DNA-Binding Proteins; D005456:Fluorescent Dyes; D005656:Fungal Proteins; D007211:Indoles; C103266:PAT1 protein, S cerevisiae; D010675:Pheromones; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C007293:DAPI; C489014:RAS1 protein, S cerevisiae; C492657:Ras1 protein, S pombe; D018631:ras Proteins