Figure 6.
Developmental RNA blots. The number of hours after the beginning of development is written above each lane. In addition, a vegetative cell lysate is included for each strain and blot. (A) Developmental expression of limB. The number of hours above each lane is the time from plating. (B) Developmental expression of the cAMP-pulsed induced gene csA (encoding the cell adhesion protein csA/gp80), the postaggregative gene LagC (required for development past the mound stage), the prestalk genes ecmA and ecmB, and the prespore gene SP60/cotC. (C) Induction of prestalk (ecmA) and prespore (SP60/cotC) gene expression in suspension culture as previously described (Mehdy and Firtel, 1985; Dynes et al., 1994). Washed, log-phase vegetative cells (6 × 105 cells/ml) were pulsed every 6 min with cAMP to a final concentration of 30 nM for 5 h at 120 rpm. Cells were then split and shaken with or without addition of cAMP to 300 μM cAMP for an additional 3 or 6 h, with cAMP supplemented to 100 μM every 3 h. RNA was isolated at the times indicated and analyzed by RNA blot hybridization.