Model for Rho/Rac-like antagonism during early elongation. (A–C) Schematic representation of signaling pathways controlling morphogenesis in dorsal and lateral cells in wt embryos (A), let-502 knockdown or mutants (B), and pix-1 or pak-1 mutants (C). Cells after a Rac1-like morphogenetic program involving PIX-1 and PAK-1 are represented in yellow, and those after a RhoA-like program involving RHO-1 and LET-502 are represented by orange. (D) Effect of Rac1/RhoA antagonism on remodeling of apical junction (left) and formation of basolateral protrusions (right).