Figure 4.

Mutations in RBP1 residues essential for dsx splicing regulation affect interaction of RBP1 with RBP1 and with TRA-2 in vivo. The photograph shows interactions in the yeast two-hybrid system between bait and prey fusion proteins as detected by activation of a lacZ reporter construct in colonies grown on galactose/X-Gal/CM–Ura, –His, and –Trp plates. Interaction assays were done in triplicate. RBP1, tra, tra-2, and bicoid bait constructs as indicated to the left were tested for interaction with wt RBP1, Gly G-A RBP1, Sub RNP RBP1, ΔPvu RBP1, ΔSR RBP1, and +1 RBP1 prey constructs as indicated on top. RBP1 variants are as described in Fig. 1. Some colonies transformed with both the wt RBP1 bait and prey constructs remained white (data not shown), probably because they fail to express the wt RBP1 bait protein.