Fig. 3. Effect of P4H1 deletion on developmental marker expression in Dictyostelium. (A) Western blot analysis for expression of the early pre-spore marker SP85 (mAb 16.1) and the late pre-spore marker SpiA (anti-SpiA) in normal (Ax3 and bsr⁺), P4H1a^- (HW288) and pgtA^- cells. Times indicate hours of starvation under ambient conditions. (B-E) Microscopic analysis of normal (Ax3) and P4H1a^- cells transfected with various promoter::bacterial ß-galactosidase reporter constructs, developed under ambient conditions and processed for ß-galactosidase activity, which deposits a dark blue precipitate. Shown are representative examples of pre-culminants or slugs expressing (B) the pre-spore cell marker PspA-Gal (strain HW405), (C) the pre-stalk A and 0 cell marker ecmA0::lacZ (HW408), (D) the pre-stalk A cell marker ecmA::lacZ (strain HW406) or (E) the pre-stalk 0 cell marker ecm0::lacZ (HW409). Anterior tips point upward.