Figure 3

Premature cell division of snf5 Δ, sol1 Δ and zfs1 Δ does not result from alteration of CDK protein levels, Rum1 activity or CDK Tyr15 phosphorylation. (a) Western blot of total cell lysates for phosphorylated-Tyr15 Cdc2, Cdc2, Cdc13 and α-tubulin (Atb2) protein levels in different small size mutants. (b) Cdc2-YFP (upper panel) or Cdc13-YFP (bottom panel) fluorescent signal in different small size mutants. Fluorescence signal of >7,000 cells was measured by flow cytometry and plotted as a moving average (window 250 cells) against forward scattered light. Note the reduced Cdc13-YFP level in the ppa2Δ strain. (c) Cell length at division of small size mutants carrying rum1⁺ or rum1Δ gene deletion (n = 60 cells). (d) Size phenotype of gene deletions in a strain carrying the Cdc13-L-Cdc2 (upper panel) or Cdc13-L-(T14A Y15F)Cdc2 (bottom panel) fusion proteins. Upper panel, n = 60 cells; bottom panel, n = 150 cells. P-value was determined by Student's t-test. WT, wild type; YFP, yellow fluorescent protein.