Figure 1.

Cell cycle-regulated expression of Cnp1. (A) Quantitative RT-PCR analysis of cnp1 expression in wild-type cells after synchronization by elutriation. Cells were synchronized in G2 by centrifugal elutriation and grown for 5 hr. Total mRNA was prepared at the indicated times postsynchronization. AS indicates a sample from the asynchronous population before elutriation. Upper panels show fold change of the indicated gene RNAs compared to a sample at 0 min. Lower panel show the percentage of septated cells and cells undergoing mitosis/G1 phase scored by DAPI and calcofluor staining at the indicated times for the same experiment. Dotted line indicates the S phase window determined by the septation index. (B) Western blot analysis of Cnp1 expression in cells after release from synchronization. Cell lysates were prepared from the same experiment described above, and processed for western blot analysis using antibodies specific for GFP and tubulin (as a loading control). Lower graph shows quantification of the Cnp1-GFP bands normalized to tubulin at each time point. Short and long time exposures (exp.) are shown for tubulin blotting.