title: Differential expression of entactin-1/nidogen-1 and entactin-2/nidogen-2 in myogenic differentiation.
abstract: Here, we show that entactin-2 expression is strongly, but transiently, induced in myogenic differentiation. Treatment of C2C12 myoblasts with actinomycin D in parallel to the induction of differentiation could demonstrate that this is due to enhanced transcription of the entactin-2 gene. Furthermore, treatment with the translation inhibitor cycloheximide could show that entactin-2 is a primary response gene. As p38 MAP kinase is an important regulator of myogenic differentiation, we also analyzed the possibility that entactin-2 might be a target of this pathway. However, using various p38 MAPK inhibitors, we could not detect involvement of p38 in entactin-2 up-regulation. Most remarkably, expression of the entactin-2 homolog entactin-1 dramatically declined in myogenesis, suggesting different functions of the two entactins in this process. A similar effect was seen in primary myoblasts isolated from two different mouse strains. Expression of high levels of entactin-1 in myoblasts using a retroviral expression system led to a higher proliferation rate both in growth and in differentiation medium and to reduced expression of various myogenic differentiation markers after the induction of differentiation. Furthermore, decreased expression of the entactin-2 gene after treatment of the cells with ent-2-specific siRNA preparation led to reduced expression of the cell cycle inhibitor p21. These data suggest important and distinct functions of entactin-1 and -2 in myogenic differentiation.
authors.affiliation: Institute of Physiology Charité, University Medicine Berlin, Arnimallee 22, 14195 Berlin, Germany.
authors.forename: Ricarda
authors.initials: R
authors.lastname: Neu
authors.forename: Stephanie
authors.initials: S
authors.lastname: Adams
authors.forename: Barbara
authors.initials: B
authors.lastname: Munz
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins; D015815:Cell Adhesion Molecules; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D024510:Muscle Development; D032446:Myoblasts / Q000187:drug effects / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C493956:CDKN1A protein, human; D002135:Calcium-Binding Proteins; D015815:Cell Adhesion Molecules; D050759:Cyclin-Dependent Kinase Inhibitor p21; D008562:Membrane Glycoproteins; C112846:Nid2 protein, mouse; D011500:Protein Synthesis Inhibitors; C029967:nidogen; D003609:Dactinomycin; D003513:Cycloheximide; D048051:p38 Mitogen-Activated Protein Kinases