title: Expression of the rat connexin 39 (rCx39) gene in myoblasts and myotubes in developing and regenerating skeletal muscles: an in situ hybridization study.
abstract: We report a detailed analysis of the expression pattern of the recently identified rat connexin gene, named rat connexin 39 (rCx39), both during embryonic development and in adult life. Qualitative and quantitative reverse transcription/polymerase chain reaction analysis showed intense expression of rCx39 restricted to differentiating skeletal muscles, with a peak of expression detected at 18 days of embryonic life, followed by a rapid decline to undetectable levels within the first week of postnatal life. A combination of the in situ hybridization technique for the detection of rCx39 mRNA and immunohistochemistry for myogenin, a myoblast-specific marker, allowed us to establish that the mRNA for this connexin was expressed in myogenin-positive myoblasts and early myotubes but disappeared in mature myotubes. Moreover, in adult animals, rCx39 mRNA was expressed in myogenic cells involved in skeletal myofiber regeneration following a crush injury. This is the first case of a connexin being mainly expressed in the myogenic cell lineage. The information presented should pave the way to novel molecular approaches in studies on the role of connexin-based gap-junctional communication in skeletal muscle differentiation and regeneration.
authors.affiliation: Department of Experimental Medicine, Section of Human Physiology, Laboratory of Neurobiology, University of Palermo, Italy. n.belluardo@unipa.it
authors.forename: N
authors.initials: N
authors.lastname: Belluardo
authors.forename: A
authors.initials: A
authors.lastname: Trovato-Salinaro
authors.forename: G
authors.initials: G
authors.lastname: Mudò
authors.forename: D F
authors.initials: DF
authors.lastname: Condorelli
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019070:Cell Lineage; D017630:Connexins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000196:embryology*; D032448:Myoblasts, Skeletal / Q000378:metabolism*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D017630:Connexins; D012333:RNA, Messenger; C506394:connexin 39, rat