FIG. 1.

Northern blot analysis of yrbA mRNA. The gene products of B. subtilis 168 trpC2 (wild-type) were analyzed by using probes specific for yrbA (probe 1) (A) and yrbB (probe 2) (B). The loci, probes used in these experiments, and prospective regions of promoters for yrbA and yrbB are shown in panel C. Total RNA (10 μg) was prepared from cells of strains TB713 (yrbA) and TB711 (yrbB) at T₅ of sporulation and analyzed by hybridization with probe 2 (lanes 7 and 8 in panel B). Arrowheads indicate the positions of mRNAs hybridized with the probes. The number of hours after the end of the exponential phase of growth is shown at the top.