Fig. 1. The Vas C terminus is required for eIF5B interaction. (A) Schematic of Vas, showing motifs characteristic of DEAD-box proteins. (B) Deletions in Vas were tested against eIF5B for direct interaction in the yeast two-hybrid system, using a plate-based assay for ß-galactosidase activity. Four replicates were tested for each sample, and were compared to a positive control (full-length Vas, 1-661) and a negative control (Vas 1-310). Interaction with eIF5B is indicated by +, and absence of interaction by -. (C) Further deletions in Vas, ending between residues 595 and 621, were tested against eIF5B in the same system. (D) The region surrounding residues V616, P617 and D618 of Vas (indicated by a box), was compared with homologous proteins in other species, and with more distantly related Drosophila DEAD-box proteins (eIF4A, Ddx1 and Dhh1). Residues that are identical between homologous proteins are shown in red.