Figure 3.

pas1⁺ is required for full cdc18⁺ mRNA induction. (A) The cdc18⁺ transcript is not fully induced during the G₁-S transition in the Δpas1 mutant. Wild-type (EV3A), Δpas1 (K182-A7), and Δpas1+ pas1⁺(Δpas1 complemented by the pas1⁺ gene integration) (K182-A7-P1) cells were grown to midlog phase at 30°C in MM (+N/2%G) and then nitrogen-starved in MM (−N/2%G) for 48 h to be arrested in G₁. The cells were then released by transfer into MM (+N/2%G) at 30°C. Cell aliquots were taken every 30 min, and cdc18⁺ expression was examined by Northern hybridization. (B) The cdc18⁺ mRNA levels shown in A were quantified with BAS2000 (Fuji Film, Tokyo, Japan). (C) cdc2⁺ transcription is not affected in the Δpas1 mutant. cdc2⁺ expression was examined by Northern hybridization with the use of the same filters used in A. (D) The cdc2⁺ mRNA levels shown in C were quantified with BAS2000 (Fuji Film).