FIG. 3.

Expression of sporulation-specific genes in wild-type and das strains. RNA was purified from cells of wild-type strain DKB414C (WT) and mutant das1-1/das1-1 (das1), das3-1/das3-1 (das3), and das4-1/das4-1 (das4) strains, as indicated to the left of the panels. Cells were harvested during logarithmic growth in YEPA medium (0 h) and at various times after transfer to sporulation medium, as indicated (in hours) below the panels. Northern blots of these RNAs were sequentially hybridized with radioactively labeled gene-specific probes (see Materials and Methods), as indicated at the top of the panels. One set of filters was hybridized with probes for transcripts from SPS4, IME2, HOP1, SPS1, IME1, and the control gene. The control probe was prepared with pC4. Two HOP1-hybridizing transcripts have been described previously (20). A duplicate set of filters was used for hybridization with probes for transcripts from SMK1 and SPS100. Only the portions of the autoradiograms that revealed hybridization with the probes are shown.