背部開口基因Raw為果蠅心肌細胞正常分化所需

[[abstract]]Previous studies have shown that raw functions in dorsal closure by restricting the expression of Dpp in dorsal ectoderm. In the raw mutant embryos the dorsal ectoderm was not closed. Since Dpp also functions in heart development by maintaining the cardiogenic gene, tinman (tin) in the underlying dorsal mesoderm, we believed that raw may play a role in heart development of insect. In this study we have found that raw is indeed required for proper differentiation of various cardial cell types, including even-skipped pericardial cells (EPCs), Odd positive pericardial cells, cardial cells, which are missing in raw mutant embryos. The precursor cells are formed initially, but missing during late embryogenesis, suggesting raw is not required for specification of these cardial cells but, is required for the survival of cardial cell types. As described above raw limit the expression of Dpp in leading edge of the embryos, loss-of-function of raw results in the ectopic expression of Dpp in dorsal ectoderm. Together with the fact that Dpp directly regulates the expression of tin in mesoderm. We expect that tin may ectopic express in mesoderm. Indeed we have observed that tin is ectopically expressed in raw mutant embryos. In addition, we have found that Wg signaling, which is also essential for cardiogenesis of Drosophila, is missing in raw mutant background. We have hypothesized that loss of Wg signaling may count for the loss of various cardial cell types in raw mutants. More studies are in progress to investigate the possibility.