title: Menin expression modulates mesenchymal cell commitment to the myogenic and osteogenic lineages.
abstract: Menin plays an established role in the differentiation of mesenchymal cells to the osteogenic lineage. Conversely, whether Menin influences the commitment of mesenschymal cells to the myogenic lineage, despite expression in the developing somite was previously unclear. We observed that Menin is down-regulated in C2C12 and C3H10T1/2 mesenchymal cells when muscle differentiation is induced. Moreover, maintenance of Menin expression by constitutive ectopic expression inhibited muscle cell differentiation. Reduction of Menin expression by siRNA technology results in precocious muscle differentiation and concomitantly attenuates BMP-2 induced osteogenesis. Reduced Menin expression antagonizes BMP-2 and TGF-beta1 mediated inhibition of myogenesis. Furthermore, Menin was found to directly interact with and potentiate the transactivation properties of Smad3 in response to TGF-beta1. Finally in concert with these observations, tissue-specific inactivation of Men1 in Pax3-expressing somite precursor cells leads to a patterning defect of rib formation and increased muscle mass in the intercostal region. These data invoke a pivotal role for Menin in the competence of mesenchymal cells to respond to TGF-beta1 and BMP-2 signals. Thus, by modulating cytokine responsiveness Menin functions to alter the balance of multipotent mesenchymal cell commitment to the osteogenic or myogenic lineages.
authors.affiliation: Department of Biology, 327 Farquharson, LSB, York University, Toronto, M3J 1P3 Ontario, Canada.
authors.forename: Arif
authors.initials: A
authors.lastname: Aziz
authors.forename: Tetsuaki
authors.initials: T
authors.lastname: Miyake
authors.forename: Kurt A
authors.initials: KA
authors.lastname: Engleka
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Epstein
authors.forename: John C
authors.initials: JC
authors.lastname: McDermott
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002460:Cell Line; D019070:Cell Lineage / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D017353:Gene Deletion; D006801:Humans; D007366:Intercostal Muscles / Q000033:anatomy & histology / Q000187:drug effects; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D039902:Multipotent Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D024510:Muscle Development / Q000187:drug effects / Q000235:genetics*; D017570:MyoD Protein / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D009928:Organ Specificity / Q000187:drug effects; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics*; D011485:Protein Binding / Q000187:drug effects; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051900:Smad3 Protein / Q000378:metabolism; D019170:Somites / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: D055396:Bone Morphogenetic Protein 2; C484898:Men1 protein, mouse; D017570:MyoD Protein; D011518:Proto-Oncogene Proteins; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D053773:Transforming Growth Factor beta1