title: Molecular analysis of fiber type-specific expression of murine myostatin promoter.
abstract: Myostatin is a negative regulator of muscle growth, and absence of the functional myostatin protein leads to the heavy muscle phenotype in both mouse and cattle. Although the role of myostatin in controlling muscle mass is established, little is known of the mechanisms regulating the expression of the myostatin gene. In this study, we have characterized the murine myostatin promoter in vivo. Various constructs of the murine myostatin promoter were injected into the quadriceps muscle of mice, and the reporter luciferase activity was analyzed. The results indicate that of the seven E-boxes present in the 2.5-kb fragment of the murine myostatin promoter, the E5 E-box plays an important role in the regulation of promoter activity in vivo. Furthermore, the in vitro studies demonstrated that MyoD preferentially binds and upregulates the murine myostatin promoter activity. We also analyzed the activity of the bovine and murine promoters in murine skeletal muscle and showed that, despite displaying comparable levels of activity in murine myoblast cultures, bovine myostatin promoter activity is much weaker than murine myostatin promoter in mice. Finally, we demonstrate that in vivo, the 2.5-kb region of the murine myostatin promoter is sufficient to drive the activity of the reporter gene in a fiber type-specific manner.
authors.affiliation: Animal Genomics, AgResearch, Ruakura Research Centre, Private Bag 3123, East St., Hamilton, New Zealand.
authors.forename: Mônica Senna
authors.initials: MS
authors.lastname: Salerno
authors.forename: Mark
authors.initials: M
authors.lastname: Thomas
authors.forename: Davanea
authors.initials: D
authors.lastname: Forbes
authors.forename: Trevor
authors.initials: T
authors.lastname: Watson
authors.forename: Ravi
authors.initials: R
authors.lastname: Kambadur
authors.forename: Mridula
authors.initials: M
authors.lastname: Sharma
mesh_terms: D000818:Animals; D002417:Cattle; D017931:DNA Primers; D024721:E-Box Elements / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D017570:MyoD Protein / Q000502:physiology; D055435:Myostatin; D011401:Promoter Regions, Genetic; D013045:Species Specificity; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D017931:DNA Primers; C525912:Mstn protein, mouse; D017570:MyoD Protein; D055435:Myostatin; D016212:Transforming Growth Factor beta