Biniou is a regulator of hand in the visceral mesoderm. A) Biniou is a regulator of hand expression in vivo. Shown are wildtype embryos carrying a bap-lacZ transgene (upper row), stained with a βGal antibody (in red) to visualize visceral mesodermal cells, and hand RNA (in green). Embryos lacking functional Biniou reveal a total loss of hand expression in the visceral mesoderm (lower row). (B) shows the result of a similar experiment. Here, the hand 3rd intron, fused to GFP, was used as a reporter. Embryos lacking Biniou reveal a complete absence of hand-GFP reporter gene expression in the visceral mesoderm. (C) Compared to the wildtype, embryos homozygous mutant for the Gli-like transcription factor Lame duck exhibit an expansion of hand expression in the visceral mesoderm (fc = founder cells, fcm = fusion competent myoblasts, vm = visceral mesoderm).