Fig. 4. The delay in prestalk gene expression and anterior prestalk cell migration in structures formed from ampA-null cells is rescued by the presence of wild-type cells. (A-C) Expression patterns of ecmA reporter after 14 hours of development by bacterially grown cells are shown. (A) Wild type; (B) ampA^–; (C) 50/50 wild type/null with reporter carried only in ampA-null cells. (D-F) 18 hours of development by bacterially grown cells is shown. (D) Wild type; (E) ampA-null; (F) 10/90 wild type/null chimera with reporter carried in null cells only. (G) 50:50 wild-type/ampA^– cells, reporter in all cells; 18 hours development. (H) 50:50 wild-type/ampA^– cells, reporter in ampA^– cells only; 18 hours development. All staining was for 1 to 2 hours.