Fig. 10. CAR1-independent defects of crtf-nulls. (A) Wild-type and crtf-null strains differentiated in shaking culture for 5 hours in the presence of exogenous 30 nM pulses of cAMP for 5 hours followed by treatment with 500 µM cAMP for an additional 5 hours. Cells were then plated on filters and examined at 10 and 24 hours. (B) Spores obtained from cells developed to fruiting bodies in Fig. 8A were analyzed. (C,D) Constitutive expression of CAR1 in crtf-nulls will rescue aggregation but not late development or sporulation of crtf-nulls. crtf-nulls carrying act15/CAR1 were developed (C) on filters for times shown and spores analyzed (D).