ZFIN ID: ZDB-PUB-961014-422
Specification of jaw muscle identity in zebrafish: correlation with engrailed-homeoprotein expression
Hatta, K., Schilling, T.F., BreMiller, R.A., and Kimmel, C.B.
Molecules that determine the specific features of individual muscles in vertebrates are unknown. Antibody labeling studies described here revealed a molecular difference among muscles in the zebrafish head, in that two functionally related jaw muscles (the levator arcus palatini and the dilator operculi), and not other head muscles, expressed engrailed-homeodomain proteins. Expression began in mesoderm-derived muscle-precursor cells in the paraxial mesenchyme and continued during muscle morphogenesis and differentiation. Growth cones of trigeminal motoneurons that innervate these muscles associated with the precursors within a few hours of the time they began to express engrailed. It is proposed that the engrailed proteins in these cells establish muscle identity and neuromuscular target recognition.