title: Expression of a developmentally regulated cross-linking intermediate filament-associated protein (IFAPa-400) during the replacement of vimentin for desmin in muscle cell differentiation.
abstract: Myogenic and neurogenic tissues of the chick embryo transiently express IFAPa-400, a high molecular weight protein that colocalizes and is copurified with intermediate filaments. Using monoclonal antibody F51H2 to identify it, we carried out immunoelectron microscopy experiments on whole-mount chick embryo cells and showed that IFAPa-400 was localized at crossing points of intermediate filaments. Also, immunoblot experiments with F51H2, anti-vimentin and anti-desmin antibodies demonstrated the complete disappearance of IFAPa-400 in those muscle cell types that change their vimentin content for desmin during embryogenesis. During in vitro myogenesis, the expression of IFAPa-400 was shown to be concurrent with the progressive replacement of vimentin by desmin in myoblasts. When long-term myotube cultures were maintained on a fibroblast-like cell layer, we observed the complete replacement of vimentin by desmin, followed by the disappearance of IFAPa-400 from the myotubes. These results suggest that IFAPa-400 might be involved in the reorganization of the intermediate filament network during muscle differentiation.
authors.affiliation: Ontogénèse et Génétique Moléculaire, Centre de Recherche du CHUL, Québec, Canada.
authors.forename: L J
authors.initials: LJ
authors.lastname: Cossette
authors.forename: M
authors.initials: M
authors.lastname: Vincent
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D002642:Chick Embryo; D003893:Desmin / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000166:cytology; D005455:Fluorescent Antibody Technique; D007381:Intermediate Filament Proteins / Q000276:immunology / Q000378:metabolism*; D007382:Intermediate Filaments / Q000737:chemistry / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D009132:Muscles / Q000166:cytology* / Q000378:metabolism; D009474:Neurons / Q000166:cytology; D014746:Vimentin / Q000032:analysis*
chemical_list: D003893:Desmin; D007381:Intermediate Filament Proteins; D014746:Vimentin