Sequence and expression of myoglianin, a novel Drosophila gene of the TGF-beta superfamily

Various members of the TGF-beta superfamily of signaling molecules are know n to have important roles in mesoderm patterning and differentiation during vertebrate and invertebrate embryogenesis. Here we characterize a new TGF- beta member from Drosophila, Myoglianin, that is most closely related to th e vertebrate muscle differentiation factor Myostatin and to vertebrate BMP- 11. Northern analysis shows that myoglianin is expressed throughout the Dro sophila life cycle. In situ hybridization detects maternally-derived transc ripts that are enriched in the pole plasm and later become enclosed in the pole cells. Between stares 11 and 14, myoglianin mRNA is exclusively detect ed in glial cells and their precursors. Following stage 14, high levels of myoglianin expression are observed in the developing somatic muscles as wel l as in visceral muscles and cardioblasts. We also show that the zygotic ex pression of a recently described Drosophila activin, which maps to the same interval 102 on chromosome 4 as myoglianin, is restricted to the developin g central and peripheral nervous system. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.