Fig. 3.

tup is required for the normal expression of early cardiac transcription factors. (A,B) Drosophila stage 11 tup^isl-1 mutants are characterized by a reduction in Tin-expressing cells (arrows). (C,D) The Pnr expression domain is strongly reduced in tup^isl-1 mutants (arrows). (E,F) Double fluorescence labeling for Dmef2 protein and pnr RNA shows the mesodermal reduction of pnr expression in tup^isl-1 mutants (arrows). (G,H) Reduced pnr expression (arrows) in the ectoderm is demonstrated by co-staining for Wg protein. (I,J) Stage 11 tup^isl-1 mutants lack cardiac Doc2-positive cells (arrows). Arrowheads indicate missing Eve-expressing cells.