title: Calpain and myogenesis: development of a convenient cell culture model.
abstract: Previous studies have led us to hypothesize that m-calpain plays a pivotal role in myoblast fusion through its involvement in cell membrane and cytoskeleton component reorganization. To support this hypothesis, a convenient and simple myoblast culture model using frozen embryonic myoblasts was developed, which resolved a number of problems inherent to cell primary culture. Biological assays on cultured myoblasts using different media to define the characteristics of the fusion process were first conducted. Proteinase was detectable before the initiation of the fusion process and was closely correlated to the phenomenon of fusion under each culture condition studied. In addition, the study of calpastatin showed that the initiation of fusion does not require a decrease in the level of this endogenous inhibitor of calpains and also confirmed that calpastatin may be implicated in the determination of the end of fusion. On the other hand, analysis of the evolution of myogenic factors revealed that myogenins, MyoD and Myf5, increase very significantly during the formation of multinucleated myotubes. Moreover, the antisense technique against myogenin is capable of preventing the process of fusion by 50%, confirming the pivotal role of this factor in the early stages of differentiation. The possible role of myogenic regulator factors on m-calpain gene expression is discussed.
authors.affiliation: ISTAB-USC-INRA 429, laboratoire de biochimie et technologie des aliments, université Bordeaux 1, avenue des facultés, 33405 Talence, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Dedieu
authors.forename: Nathalie
authors.initials: N
authors.lastname: Dourdin
authors.forename: Elise
authors.initials: E
authors.lastname: Dargelos
authors.forename: Sylvie
authors.initials: S
authors.lastname: Poussard
authors.forename: Philippe
authors.initials: P
authors.lastname: Veschambre
authors.forename: Patrick
authors.initials: P
authors.lastname: Cottin
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Brustis
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002154:Calpain / Q000502:physiology*; D002459:Cell Fusion; D002478:Cells, Cultured; D008954:Models, Biological; D024510:Muscle Development / Q000502:physiology*; D032446:Myoblasts / Q000502:physiology*; D018008:Myogenin / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002135:Calcium-Binding Proteins; C503803:Myog protein, rat; D018008:Myogenin; C033668:calpastatin; D002154:Calpain