CGC Bibliography Paper 3138

MyoD and the specification of muscle and non-muscle fates during postembryonic development of the C. elegans

Harfe BD, Branda CS, Krause M, Stern MJ, Fire A

Medline:

98274207

Citation:

Development 125: 2479-2488 1998

Type:

ARTICLE

Genes:

ceh-24 egl-15 hlh-1 hlh-8 lin-12 myo-3 sup-5

Abstract:

Basic-helix-loop helix factors of the myoD/myf5/myogenin/MRF4 family have been implicated in acquisition and elaboration of muscle cell fates. Here we describe both myogenic and non-myogenic roles for the Caenorhabditis elegans member of this family (CeMyoD) in postembryonic mesodermal patterning. The postembryonic mesodermal lineage in C, elegans provides a paradigm for many of the issues in mesodermal fate specification: a single mesoblast ('M') divides to generate 14 striated muscles, 16 non-striated muscles, and two non-muscle cells. To study CeMyoD function in the M lineage, we needed to circumvent an embryonic requirement for the protein. Two approaches were used: (1) isolation of mutants that decrease CeMyoD levels while retaining viability, and (2) analysis of genetic mosaics that had lost CeMyoD in the M lineage. With either manipulation, we observed a series of cell-fate transformations affecting a subset of both striated muscles and non-muscle cells. In place of these normal fates, the affected lineages produced a number of myoblast-like cells that initially failed to differentiate, instead swelling to acquire a resemblance to sex myoblast (M-lineage-derived precursors to non-striated uterine and vulval muscles). Like normal ses myoblasts, the ectopic myoblast-like cells were capable of migration and proliferation followed by differentiation of progeny cells into vulval and uterine muscle, Our results demonstrate a cell-intrinsic contribution of CeMyoD to specification of both non-muscle and muscle fates.