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Acceleration of somitic myogenesis in embryos of myogenin promoter‐MRF4 transgenic mice
Author(s) -
Block Nancy E.,
Zhu Zhimin,
Kachinsky Amy M.,
Dominov Janice A.,
Miller Jeffrey Boone
Publication year - 1996
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/(sici)1097-0177(199612)207:4<382::aid-aja3>3.0.co;2-d
Subject(s) - myogenesis , myogenin , myod , biology , myogenic regulatory factors , myosin , transgene , somite , microbiology and biotechnology , myocyte , myod protein , embryo , embryogenesis , genetics , gene
The four muscle regulatory factors (MRFs) of the MyoD family are expressed in distinct temporal and spatial patterns in developing somites. To examine MRF function and regulation in somites, we generated myogenin promoter‐MRF4 transgenic mice in which MRF4 was expressed in rostral somites about a half day earlier than normal. We found that the transgene, which was expressed at about the same level as endogenous MRFs, did not noticeably alter developing or adult mice, whereas the rostral somites of transgenic embryos showed accelerated myocyte formation, as well as precocious expression of the endogenous MRF4 gene. In an individual transgenic somite, MRF4 was expressed in both presumptive myotomal (mesenchymal) and dermatomal (epithelial) cells. Transgenic dermatomal cells also contained myogenin, which is expressed early in myogenesis, but did not contain myosin, which is expressed late in myogenesis. In transgenic myotomal cells, in contrast, precocious expression of MRF4 accelerated late events in myogenesis, including myosin expression and striated myofibril formation. MRF function, therefore, appears to be differentially regulated in dermatomal and myotomal cells. © 1996 Wiley‐Liss, Inc.