BONE MORPHOGENETIC PROTEIN-2 (BMP-2) INHIBITS MUSCLE DEVELOPMENT AND PROMOTES CARTILAGE FORMATION IN CHICK LIMB BUD CULTURES

Bone morphogenetic proteins (BMPs) induce ectopic cartilage and bone w hen implanted intramuscularly in adult rats. Expression data suggest t hat BMPs signal skeletal development in embryos. An important question is which cells are targets of BMP signaling in adult and embryonic ti ssues. Here, rye examined the effect of BMP-P on micromass cultures of chick limb bud mesenchyme. We report that BMP-2 promotes formation of cartilage and simultaneously inhibits development of muscle cells. To follow the fate of presumptive muscle cells, we replaced chick somite s with quail somites at the wing level and made micromass cultures fro m the chimeric wings. In untreated cultures, quail cells formed muscle but not cartilage. In BMP-2-treated cultures, quail cells disappeared altogether. This suggests that BMP-2 may simultaneously promote carti lage differentiation and reduce the presumptive myogenic cell populati ons in regions of skeletal development. (C) 1996 Academic Press, Inc.