The interaction between a1 and 2 coregulators makes

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Unformatted text preview: of the 1 activator and the 2 repressor accounts for both and a cell types. By contrast, the a1 protein expressed in a-type cells performs no function necessary for mating or differentiation into a cells. The interaction between a1 and 2 coregulators makes MATa/ MAT heterozygous diploids sterile. 5. Heterothallic yeast strains are unable to switch mating type, while homothallic yeast strains can switch from a to and back again. Mating type switching in homothallic strains is controlled by the activity of the MAT locus, the HO gene, the alleles at HML and HMR, and the four SIR genes. Two general rules govern HO-mediated switching: (1) Cells always switch in pairs, and (2) cells must gain competence to switch by undergoing at least one cell division. 6. a and cells communicate through pheromones determined by a-specific and -specific genes. a cells secrete a pheromone, while cells secrete pheromone. Each cell type carries receptors for the opposite type pheromone. The binding of pheromone from the oppos...
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This note was uploaded on 10/03/2013 for the course BI 206 taught by Professor Celenza during the Spring '08 term at BU.

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