Cell cycle regulation of SW15 is required for mother-cell-specific HO transcription in yeast.
In haploid homothallic yeast, cell division gives rise to a mother cell that transiently transcribes the HO gene (as it undergoes START) and a daughter cell that does not. Consequently, only mother cells switch their mating types. Here, we test the proposition that a transcription factor called SWI5 is the "determinant" of mother-cell-specific HO transcription; that is, that SWI5 is the only factor missing in daughter cells. We show that SWI5 RNAs are cell-cycle regulated so that they are only produced after the post-START window of HO transcription. This regulation is vital for mother-cell specificity since constitutive transcription of SWI5 causes daughter cells to switch their mating types. We propose that SWI5 gene products are partitioned asymmetrically at cell division.
D001483:Base Sequence; D002453:Cell Cycle; D003433:Crosses, Genetic; D005800:Genes, Fungal; D005809:Genes, Regulator; D005838:Genotype; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics*; D014158:Transcription, Genetic