Fig. 9. Cell-specific gene expression patterns in crtf-nulls. (A) Expression of prestalk (ecmA) and prespore (cotB, psA) genes in wild-type and crtf-null strains differentiated in shaking culture in the presence of exogenous pulses of cAMP (P) followed by treatment without (-) or with (+) 500 µM cAMP. (B) spiA mRNA expression in wild-type and crtf-null strains at various stages of development (hours). (C) Spatial expression of prestalk ecmA/lacZ and prespore psA/lacZ in crtf-nulls; red arrows indicate prestalk regions of slugs.