A membrane guanylate cyclase Drosophila homolog gene exhibits maternal and zygotic expression.

A putative membrane form of guanylate cyclase gene was identified in region 32 of the second chromosome of Drosophila melanogaster. The Drosophila protein has a single hydrophobic sequence that divides the protein into a putative extracellular region and a cytoplasmic catalytic region which contains tyrosine kinase and cyclase domains showing varying degrees of conservation with other guanylate and adenylate cyclases. The gene shows a very interrupted organization with small exons separated by small introns and a low level of expression. Transcripts have been localized in situ during oogenesis in the germarium and later in stages 10-14 of egg chamber development. The putative maternal transcript can be seen in very early embryos and reappears later as a product of zygotic gene expression.