We are interested in the mechanisms controlling embryonic gene expression that result in the differentiation of omnipotent cells into one of several cell fates. Our model system revolves around myogenesis during embryonic development in the nematode C. elegans. Specifically, we have focused on the nematode homologs of genes encoding myogenic regulatory factors known to be critical in vertebrate myogenesis (eg. MyoD, E12/Da, and MEF2). We want to know what role, if any, these homologs play during nematode myogenesis. The simplicity of the nematode, both in terms of the anatomy and the developmental complexity, allows us to study the expression of these factors in detail. We can also address the function of these genes by inactivating them through mutations. We have shown that although CeMyoD is required to generate functional muscle during embryogenesis it is not required for its determination; C. elegans striated muscle cells undergo substantial differentiation in the absence of CeMyoD. The nematode homologs of both E12/Da and MEF2 also show differences in expression patterns and functions when compared to the vertebrates and Drosophila. Despite the extreme conservation of these factors, from nematodes to humans, the emerging picture is that the developmental processes in which they function are far less conserved.
Krause, M.W., Fire, A., White-Harrison, S., Priess, J., and Weintraub, H. (1990). CeMyoD Accumulation Defines the Bodywall Muscle Cell Fate During C. elegans Embryogenesis. Cell 63, 907-922.
Chen, L, Krause, M., Sepanski, M., and Fire, A. (1994). The C. elegans MyoD homologue HLH-1 is essential for proper muscle function and complete morphogenesis. Development, 120, 1631-1641.
Krause, M.W., White-Harrison, S., Si-Qun, X., Chen, L., and Fire, A. (1994). Elements Regulating Cell- and Stage-Specific Expression of the C. elegans MyoD Family Homolog hlh-1. Devel. Biol., 166, 133-148.
Krause, M. (1995). MyoD and Myogenesis in C. elegans. BioEssays, 17, 219-22