title: CELF and PTB proteins modulate the inclusion of the β-tropomyosin exon 6B during myogenic differentiation.
abstract: Exon 6B from the chicken β-tropomyosin pre-mRNA is alternatively spliced during myogenic differentiation. Exon 6B is excluded in mRNA from myoblasts and included in mRNA from myotubes. We investigated the regulation of exon 6B inclusion ex vivo in a quail myogenic cell line, which behaves as myoblasts in undifferentiated state and as myotubes after differentiation. We show that the β-tropomyosin exon 6B is a novel target of CUG-BP and ETR-3-like factor (CELF). Overexpression of CELF proteins in myoblasts activates splicing of exon 6B. Using a dominant-negative form of CELF4, we demonstrate that CELF proteins are involved in switching splicing from exon 6A towards exon 6B inclusion during myogenic differentiation. We also found that polypyrimidine tract binding protein (PTB) is required for splicing repression of exon 6B in myoblasts. CELF and PTB proteins exhibit antagonistic properties toward inclusion of exon 6B during myogenic differentiation. Our results suggest that a change in the protein level of CUGBP1 and PTB proteins, associated with a distinct pattern of PTB during the transition from myoblasts to myotubes is one of the parameters involved in regulating splicing of exon 6B during myogenesis.
authors.affiliation: Centre de Génétique Moléculaire, FRE 3144, CNRS, Gif sur Yvette, France, Université Paris XI, Orsay, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Sureau
authors.forename: Jérôme
authors.initials: J
authors.lastname: Saulière
authors.forename: Alain
authors.initials: A
authors.lastname: Expert-Bezançon
authors.forename: Joëlle
authors.initials: J
authors.lastname: Marie
mesh_terms: D017398:Alternative Splicing / Q000187:drug effects / Q000235:genetics*; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D005091:Exons / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D024510:Muscle Development / Q000187:drug effects / Q000235:genetics*; D038941:Polypyrimidine Tract-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011784:Quail / Q000196:embryology; D012322:RNA Precursors / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014335:Tropomyosin / Q000235:genetics* / Q000378:metabolism
chemical_list: D012322:RNA Precursors; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D014335:Tropomyosin; D038941:Polypyrimidine Tract-Binding Protein