Biochemical analysis of torso and D-raf during Drosophila embryogenesis: implications for terminal signal transduction.

摘要: Abstract Determination of anterior and posterior terminal structures Drosophila embryos requires activation two genes encoding putative protein kinases, torso D-raf. In this study, we demonstrate that Torso has intrinsic tyrosine kinase activity show it is transiently phosphorylated (activated) at syncytial blastoderm stages. proteins causing a gain-of-function phenotype are constitutively phosphorylated, while loss-of-function lack activity. The D-raf gene product, which required for function, identified as 90-kDa with serine/threonine D-Raf expressed throughout embryogenesis; however, the phosphorylation state changes during development. wild-type embryos, hyperphosphorylated 1 to 2 h after egg laying, thereafter only most highly form detected. Embryos lacking activity, significant reductions in expression rather than major alterations protein's state. This report provides first biochemical analysis signal transduction pathway embryos.