UASt regulatory sequences drive expression of a XbaI fragment containing a RhoGEF2 cDNA corresponding to the RhoGEF2-RE transcript (made by joining a partial cDNA encompassing the region from a central EcoRI site to the 3' end of RhoGEF2 with a cDNA representing the RhoGEF2-RE transcript from the same EcoRI site to the 5' end).