Olson, Eric N.2010-07-122010-07-122007-12-18https://hdl.handle.net/2152.5/437The early morphogenetic mechanisms involved in heart formation are evolutionarily conserved. The Drosophila heart, known as the dorsal vessel, functions as a pulsatile tube-like organ containing an inner layer of contractile cardial cells that adhere tightly to an adjacent layer of pericardial cells. A genetic screen for genes that control Drosophila heart development revealed a cardiac defect in which pericardial and cardial cells dissociate causing loss of cardiac function and embryonic lethality. This phenotype resulted from mutations in the genes encoding HMG-CoA Reductase, downstream enzymes in the mevalonate pathway, and G-protein Ggamma 1, which is geranylgeranylated, thus representing an endpoint of isoprenoid biosynthesis. These findings reveal a cardial cell-autonomous requirement of Ggamma 1 geranylgeranylation for heart formation and suggest the involvement of the mevalonate pathway in congenital heart disease. In addition, we found that the heterotrimeric G proteins Gbeta 13F and G-oalpha 47A together with the RGS (regulator of G protein signaling) protein Loco function in the same pathway as Ggamma 1 to regulate septate junction formation in cardial cells of the Drosophila heart. We also present evidence that the septate junction protein Sinuous interacts with Pericardin, a matrix protein secreted by pericardial cells, providing the molecular basis for cardial-pericardial cell adhesion and serving as a mediator of the actions of the mevalonate pathway and heterotrimeric G protein signaling in Drosophila heart development.Electronicapplication/pdfenHeartDrosophila melanogasterGenetic TestingThesisborn digital759399923