Figure 4.
F-actin accumulation and filopodia formation are induced by WIPa. (A) Expression of hairpin WIPa hp WIPa construct reduces WIPa mRNA level. RT-PCR reactions were performed using mRNA purified from 5 h pulsed Dictyostelium cells. Expression of other genes essential for F-actin regulation was unaffected. (B) F-actin organization in cells expressing hpWIPa or WIPa mutants. At least 150 cells taken from three independent experiments were used for quantitation of leading edge F-actin content (C) and filopodia number (D). Quantitation of in vivo YFP signal revealed equivalent levels of WIPa expression in each cell type. WIPa-WASPTK refers to the overexpression of wild-type WIPa in the WASP TK background.