Figure 6.

Tra1 and Gcn5 repress sexual differentiation, but act through independent pathways. (A, B) Expression analysis of ste11⁺ (A) and mei2⁺ (B) by quantitative RT–PCR of RNA prepared from h⁹⁰ homothallic strains. Cells were grown to mid-log phase in minimal medium in the presence of nutrients, and then shifted for 4 h to either rich medium (dark grey) or starvation medium (light grey). act1⁺ served as a control for normalization across RT–PCR samples. Normalized ste11⁺ or mei2⁺ mRNA levels in a wild-type strain grown in rich medium were set at 1 to allow comparisons across culture conditions and mutant strains. Each column represents the mean value±s.e. (n=4). (C) Cells were grown to mid-log phase in minimal medium in the presence of nutrients, and examined under direct light microscopy for conjugation and sporulation. Mating efficiency (%) was calculated by dividing the number of zygotes or asci (each counted as two cells) by the number of total cells (at least 300 cells). Each column represents the mean value±s.e. (n=4).