title: Expression of MRF4 protein in adult and in regenerating muscles in Xenopus.
abstract: In Xenopus, previous studies showed that the transcripts of the myogenic regulatory factor (MRF) MRF4 accumulate during skeletal muscle differentiation, but nothing is known about the accumulation of XMRF4 protein during myogenesis. In this report, an affinity-purified polyclonal antibody against Xenopus MRF4 was developed and used to describe the pattern of expression of this myogenic factor in the adult and in regenerating muscles. From young forming myotubes, XMRF4 protein persistently accumulated in nuclei during the regeneration process and was strongly expressed in nuclei of adult muscles. No selective accumulation of XMRF4 protein was detectable at neuromuscular junctions, but XMRF4 immunoreactivity was observed in sole plate nuclei as well as in extrasynaptic myofiber nuclei. We also report that XMRF4 protein accumulated before the establishment of neuromuscular connections, showing that innervation is not necessary for the appearance of XMRF4 protein during muscle regeneration.
authors.affiliation: Biologie du Développement et de la Différenciation Musculaire, LNRS UMR 7060 CNRS, Université René Descartes, Paris, France.
authors.forename: Christel
authors.initials: C
authors.lastname: Becker
authors.forename: Bruno
authors.initials: B
authors.lastname: Della Gaspera
authors.forename: Michèle
authors.initials: M
authors.lastname: Guyot
authors.forename: Evelyne
authors.initials: E
authors.lastname: Donsez
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Armand
authors.forename: Frédéric
authors.initials: F
authors.lastname: Charbonnier
authors.forename: Thierry
authors.initials: T
authors.lastname: Launay
authors.forename: Christophe
authors.initials: C
authors.lastname: Chanoine
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000378:metabolism; D015151:Immunoblotting; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D018482:Muscle, Skeletal / Q000166:cytology; D009132:Muscles / Q000166:cytology* / Q000294:innervation / Q000502:physiology*; D018006:Myogenic Regulatory Factors / Q000096:biosynthesis*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012038:Regeneration; D013997:Time Factors; D014981:Xenopus
chemical_list: D018006:Myogenic Regulatory Factors; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C063403:myogenic factor 6; D005982:Glutathione Transferase