| First Author | Tajbakhsh S | Year | 1996 |
| Journal | Dev Dyn | Volume | 206 |
| Issue | 3 | Pages | 291-300 |
| PubMed ID | 8896984 | Mgi Jnum | J:33706 |
| Mgi Id | MGI:81183 | Doi | 10.1002/(SICI)1097-0177(199607)206:3<291::AID-AJA6>3.0.CO;2-D |
| Citation | Tajbakhsh S, et al. (1996) Gene targeting the myf-5 locus with nlacZ reveals expression of this myogenic factor in mature skeletal muscle fibres as well as early embryonic muscle. Dev Dyn 206(3):291-300 |
| abstractText | We have introduced the nlacZ reporter gene into the locus of the myogenic factor gene myf-5 by homologous recombination in embryonic stem (ES) cells. Targeted ES clones were injected into precompaction morula, and the B- galactosidase expression pattern was monitored. These mice permit the sensitive visualization of myf-5 expression throughout the embryo, and provide a standard for comparing it with that seen with different myf-5/nlacZ transgenes. Thus, in a comparison using ES cells in chimaeric embryos containing the targeted or randomly integrated myf-5/nlacZ construct, we demonstrate that 5.5 kbp of myf-5 upstream Banking sequence including exon1 and most of intron1 directs some skeletal muscle expression, but this is neither qualitatively nor quantitatively equivalent to that of the endogenous gene. Myf-5 is expressed early, before terminal myogenesis takes place in the medial half of the somite, and subsequently it is a major myogenic factor as skeletal muscle forms. All skeletal muscle shows P-galactosidase activity, even after birth, indicating that myf-5 expression is not confined to primary myotubes, which are derived from embryonic myoblasts, but is also present in muscles containing different adult fibre types. The presence of myf-5 transcripts from the endogenous gene in older muscle was confirmed by in situ hybridization. These results suggest that the myf-5 gene is not activated in only a subset of muscle cells and are consistent with the results on the MyoD knockout mice. (C) 1996 Wiley-Liss, Inc. |
