SAE3 Homolog (SAE3)

Swi5 transcription factor regulates the expression of the SIC1 Cdk inhibitor in late mitosis. Swi5 might control other genes with roles in ending mitosis. A gene with a Swi5-binding site in the promoter that encoded a protein with high homology to Pcl2, a cyclin-like protein that associates with the Cdk Pho85. PCL9, is indeed regulated by Swi5 in late M phase, the only cyclin known to be expressed at this point in the cell cycle. The Pcl9 protein is associated with a Pho85-dependent protein kinase activity, and the protein is unstable with peak levels occurring in late M phase. The expression of PCL2 and PCL9 at this stage of the cell cycle implies a role for the Pho85 Cdk at the end of mitosis. Consistent with this a synthetic interaction was observed between pho85delta and strains deleted for SIC1, SWI5, and SPO12.