FIG. 3.
UV-induced Ddc1 phosphorylation depends upon the presence of Mec1 kinase consensus sites. (A) Outline of the Cdc28 (gray) and Mec1 (black) putative phosphorylation target sites in Ddc1. Cdc28 and Mec1 target sites were mutated to alanine in ddc1-M3 and ddc1-M8 mutant strains, respectively. The ddc1-M11 mutant strain contains a combination of all of these mutations. (B) Strains YLDN25 (WT), YLDN17 (ddc1-M3), YLDN23 (ddc1-M8), and YLDN24 (ddc1-M11) were arrested with nocodazole and either UV irradiated (75 J/m2) or mock treated. Protein extracts prepared immediately after UV treatment were separated by SDS-PAGE and analyzed with anti-Ddc1 antibodies.