Fig. 1. Molecular lesion of gyc76C²³⁸⁸ and gyc76C RNA expression in the Drosophila embryo.

A single nucleotide change from T to G in the 5′ intron sequence following exon 16 changes the conserved GU at the splice donor site to GG. This nucleotide change is followed by the insertion of 92 base pairs of intron 6 that contain an in-frame stop codon before the guanylyl cylcase domain (A). gyc76C RNA is expressed in the circular visceral mesoderm (CVM) (B, large arrow) overlying the migrating salivary gland (B, arrowhead) and in the fat body (FB) (B, small arrows) underlying the gland at stage 13, in the lateral body wall muscles (C, arrow) and in the tendon cells (D, arrow) at stage 15 and salivary gland (E, arrow) and midgut constrictions (F, arrow) at stage 16. gyc76C RNA is also expressed in the developing trachea (G) when primary branches such as the dorsal trunk (DT) are migrating out (G, arrow) at stage 12, when the DT undergoes anastomosis (G′) at stage 13 and is enriched apically in DT cells (G″) at stage 15. All embryos shown were processed for in situ hybridization to gyc76C RNA. Scale bar in B and G represents 20 µm.