FIG. 3.

SXI2a induces sexual development in α cells. (A) Expression of SXI2a in haploid α cells results in filamentation and spore formation. Panels show the amount of filamentation achieved under mating conditions for each of the strain combinations indicated (from left to right): a wild-type cross between haploid a and α strains (a × α), a haploid α strain (α), and a haploid α strain expressing the a-specific gene SXI2a (α+SXI2a) (B) Schematic representation of filament formation in a/a diploid cells expressing SXI1α and a table showing analysis of spore products. The “parent genotype” is that of the homozygous a/a diploid used in the experiment. The “spore phenotypes” are those combinations expected to result from sporulation of the parent diploid. The frequencies presented result from an analysis of 39 random spores that were micromanipulated, germinated, and analyzed from the a/a+SXI1α strain under filamentation conditions. n/a, not applicable. The structure on the side of the filament cells represents an unfused clamp connection.