title: Alterations in somite patterning of Myf-5-deficient mice: a possible role for FGF-4 and FGF-6.
abstract: Mice carrying a targeted mutation in the gene for the myogenic factor Myf-5 fail to form major parts of the ribs, which leads to an unstable thorax and perinatal death. Here, we report that somites of Myf-5-deficient mice lack the expression of FGF-4 and FGF-6 while TGF beta-2 is expressed normally. Early sclerotomal markers, such as Pax-1 reveal no substantial reduction of sclerotome size. At E11.5 the condensing mesenchyme of the rib anlagen is considerably reduced in size in Myf-5 mutant mice. This may be caused by the lack of Myf-5-positive, FGF-expressing cells which normally are in close contact with the lateral sclerotome generating the rib progenitors. The potential role of FGFs and TGF beta on sclerotome formation is demonstrated in micromass cultures of early somites. Combinations of FGF-4 or FGF-6 with TGF beta-2 potentiate chondrogenesis suggesting that these growth factors emanating from early myotomal and dermomyotomal cells may have instructive or permissive effects on differentiation or outgrowth of sclerotomal cells.
authors.affiliation: Department of Cell and Molecular Biology, University of Braunschweig, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Grass
authors.forename: H H
authors.initials: HH
authors.lastname: Arnold
authors.forename: T
authors.initials: T
authors.lastname: Braun
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D004268:DNA-Binding Proteins; D004357:Drug Synergism; D005260:Female; D051519:Fibroblast Growth Factor 4; D051522:Fibroblast Growth Factor 6; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D015870:Gene Expression; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009124:Muscle Proteins / Q000235:genetics*; D009154:Mutation; D051787:Myogenic Regulatory Factor 5; D011247:Pregnancy; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D012272:Ribs / Q000002:abnormalities* / Q000196:embryology; D015534:Trans-Activators; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D004268:DNA-Binding Proteins; C496446:Fgf4 protein, mouse; C486115:Fgf6 protein, mouse; D051519:Fibroblast Growth Factor 4; D051522:Fibroblast Growth Factor 6; D009124:Muscle Proteins; C497418:Myf5 protein, mouse; D051787:Myogenic Regulatory Factor 5; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D005346:Fibroblast Growth Factors