Fig. 1. The RhoGAP protein K09H11.3 is required to control membrane ruffling in the early C. elegans embryo. (A) Pictures from time-lapse studies of wild-type and K09H11.3 RNAi-treated embryos. K09H11.3 RNAi treatment was performed by feeding dsRNA-expressing bacteria targeting the RhoGAP domain containing the N-terminus of the K09H11.3 gene (rga-3). Embryos are grown at 20°C and mounted for microscopy: anterior ruffling is more pronounced in the RNAi-treated embryo (lower panel) than in the wild-type embryo (upper panel). This exaggerated ruffling also persists longer in the RNAi-treated embryo than in wild type. (B) Quantification of ruffles in embryos up to pronuclear meeting (PNM) in wild type (n=8) and after K09H11.3 RNAi treatment (n=13). The ruffles were counted from time-lapse movies of individual embryos. The average number of ruffles per embryo at a given time point is indicated. (C) Schematic drawing of different RhoGAP-domain-containing proteins in humans (hs), Xenopus laevis (Xl), C. elegans (Ce) and Saccharomyces cerevisiae (Sc). The RhoGAP domain (green) is present in most RhoGAPs in the more C-terminal part of the protein. RGA-3 and RGA-4 belong to a family of uncharacterized RhoGAP-domain proteins, which carry the GAP domain at the N-terminus of the protein. The SH2 domain, the C1 domain and the CRAL/Trio domain are depicted in red, blue and yellow, respectively. Scale bar: 20 µm.