MULTIPLE ROLES FOR NOTCH IN DROSOPHILA MYOGENESIS

Notch plays a role in many cell fate decisions in the developing Droso phila embryo, often at successive stages during the formation of a sin gle tissue. In the embryonic mesoderm, Notch is involved in the proces s by which muscle progenitors are selected from a field of equivalent myoblasts. We have investigated the roles of Notch in somatic myogenes is and show that Notch can affect at least two additional steps in mus cle development. Subsequent to the initial specification of progenitor s, myoblast identity remains sensitive to mesodermal Notch activity un til the time of fusion. Additionally, Notch is capable of suppressing muscle development nonautonomously by regulating a signal that emanate s from the ectoderm. (C) 1998 Academic Press.