Reference number : GC-2017-Q1-02233, amendment number : , agreement type : G, recipient legal name : Whiteway, Malcolm (Concordia University)|Whiteway, Malcolm (Université Concordia), recipient country : CA, recipient province : nan, recipient city : Quebec|Québec, recipient postal code : nan, program name english : Discovery Grants Program - Individual, program name french : Programme de subventions à la découverte - individuelles, program purpose english : The exchange of genetic information through mating is a central biological process. In the ascomycete fungi, mating has been well studied in S. cerevisiae where a receptor/G protein complex activates a MAP kinase module controlling cell cycle arrest, gene expression, and morphology. In the related ascomycete Candida albicans, key elements of the circuitry differ from the S. cerevisiae model. Comprehending the logic of these differences is critical to a full understanding of the fungal mating process. We will investigate two areas where the circuits are different - the requirement for the opaque state for C. albicans mating, and the role of the G alpha subunit. Haploid S. cerevisiae cells are inherently mating competent, while C. albicans cells require a cell-type-dependent epigenetic switch to mating-competence. In the laboratory this switch is rare, and mating competence infrequent. We have identified the ofr1 mutation that allows the cells to bypass normal requirements for mating, and switch to the opaque state and mate even as a/&alpha; heterozygotes. We will follow up in two ways &ndash; establish the molecular basis for the ofr1 mutation allowing mating, and identify and characterize other mutations that permit a/&alpha; heterozygotes to mate. We will first use double mutant analysis to establish which circuits are required for ofr1-triggered mating - mutating the mating signalling pathway (STE4), the classic white-opaque switching machinery (WOR1) and glucosamine uptake (NGT1). To find new elements regulating mating we will identify other mutations in the GRACE collection allowing switching to the opaque form while MTL heterozygous. Strains where gene inactivation stimulates opaque cell formation will be identified as showing the enhanced phloxine staining characteristic of opaque cells. We will also investigate G protein circuitry of C. albicans. Normally the &alpha; and &beta;&gamma; subunits play opposing roles in the mating process. In C. albicans we have shown that both &alpha; and &beta;&gamma; are required for mating. We will determine if the &alpha; and &beta;&gamma; elements perform independent functions required for mating, or coordinate a single function. To distinguish these possibilities we will activate a variety of downstream elements in the pathway, and establish if the activated element suppresses either or both of the &alpha; and &beta; mutants. We will also assess other cellular process influenced by the pheromone pathway such as the white-opaque switch to assess whether the roles of &alpha; and &beta; are different., program purpose french : The exchange of genetic information through mating is a central biological process. In the ascomycete fungi, mating has been well studied in S. cerevisiae where a receptor/G protein complex activates a MAP kinase module controlling cell cycle arrest, gene expression, and morphology. In the related ascomycete Candida albicans, key elements of the circuitry differ from the S. cerevisiae model. Comprehending the logic of these differences is critical to a full understanding of the fungal mating process. We will investigate two areas where the circuits are different - the requirement for the opaque state for C. albicans mating, and the role of the G alpha subunit. Haploid S. cerevisiae cells are inherently mating competent, while C. albicans cells require a cell-type-dependent epigenetic switch to mating-competence. In the laboratory this switch is rare, and mating competence infrequent. We have identified the ofr1 mutation that allows the cells to bypass normal requirements for mating, and switch to the opaque state and mate even as a/&alpha; heterozygotes. We will follow up in two ways &ndash; establish the molecular basis for the ofr1 mutation allowing mating, and identify and characterize other mutations that permit a/&alpha; heterozygotes to mate. We will first use double mutant analysis to establish which circuits are required for ofr1-triggered mating - mutating the mating signalling pathway (STE4), the classic white-opaque switching machinery (WOR1) and glucosamine uptake (NGT1). To find new elements regulating mating we will identify other mutations in the GRACE collection allowing switching to the opaque form while MTL heterozygous. Strains where gene inactivation stimulates opaque cell formation will be identified as showing the enhanced phloxine staining characteristic of opaque cells. We will also investigate G protein circuitry of C. albicans. Normally the &alpha; and &beta;&gamma; subunits play opposing roles in the mating process. In C. albicans we have shown that both &alpha; and &beta;&gamma; are required for mating. We will determine if the &alpha; and &beta;&gamma; elements perform independent functions required for mating, or coordinate a single function. To distinguish these possibilities we will activate a variety of downstream elements in the pathway, and establish if the activated element suppresses either or both of the &alpha; and &beta; mutants. We will also assess other cellular process influenced by the pheromone pathway such as the white-opaque switch to assess whether the roles of &alpha; and &beta; are different., agreement title english : Fungal mating circuity, agreement title french : Fungal mating circuity, agreement number : RGPIN, agreement value : 200000.0, agreement start date : 2017-05-10, agreement end date : nan, description english : nan, description french : nan, expected results english : nan, expected results french : nan, additional information english : Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023), additional information french : Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023), owner organization : nserc-crsng, owner organization title : Natural Sciences and Engineering Research Council of Canada | Conseil de recherches en sciences naturelles et en génie du Canada