Fig. 3
From: Whi7 is an unstable cell-cycle repressor of the Start transcriptional program
Cell cycle regulation of Whi7 protein stability by Cdc28 phosphorylation. a Cells of the WHI7-HA (JCY1728) strain were incubated for 2 h in the presence of 15 μg mL−1 nocodazole (>90% of cells arrested at G2/M phase). Whi7 protein stability was analyzed as described in Fig. 2. b Wild-type (JCY1746) and cdc15 mutant (JCY1802) cells expressing GFP-tagged Whi7 were incubated at 37 °C for 3 h (>95% of cdc15 mutant cells arrested at telophase), and then Whi7 protein stability was analyzed. c left panel: cdc15 cells expressing GFP-tagged Whi7 (JCY1802) were arrested in telophase by incubation at 37 °C. After 3 h, cells were released from the arrest and after 50 min, 100 μg mL−1 cycloheximide was added. Whi7, as well as Clb2 and Sic1 as controls of cell cycle progression, were analyzed. No budding occurred during the experiment confirming that cells remain in G1 phase. right panel: wild type (JCY1746) and GAL1:CLN3 cln1 cln2 (JCY2008) cells expressing GFP-tagged Whi7 were grown on galactose, transferred to YPD medium and after 3 h (100% of cell in G1 in the mutant strain) Whi7 protein stability was analyzed. d Wild type (JCY1746) and cdc28 mutant (JCY1789) cells expressing GFP-tagged Whi7 were incubated at 37 °C for 3 h and then Whi7 protein stability was analyzed. e Whi7 protein stability in whi7 mutant cells (JCY1819) transformed with a centromeric plasmid that expresses the HA-tagged wild type (pWHI7) or a mutated protein in all consensus CDK phosphorylation sites (pWhi7-NP)
