title: A Twist2-dependent progenitor cell contributes to adult skeletal muscle.
abstract: Skeletal muscle possesses remarkable regenerative potential due to satellite cells, an injury-responsive stem cell population located beneath the muscle basal lamina that expresses Pax7. By lineage tracing of progenitor cells expressing the Twist2 (Tw2) transcription factor in mice, we discovered a myogenic lineage that resides outside the basal lamina of adult skeletal muscle. Tw2+progenitors are molecularly and anatomically distinct from satellite cells, are highly myogenic in vitro, and can fuse with themselves and with satellite cells. Tw2+progenitors contribute specifically to type IIb/x myofibres during adulthood and muscle regeneration, and their genetic ablation causes wasting of type IIb myofibres. We show that Tw2 expression maintains progenitor cells in an undifferentiated state that is poised to initiate myogenesis in response to appropriate cues that extinguish Tw2 expression. Tw2-expressing myogenic progenitors represent a previously unrecognized, fibre-type-specific stem cell involved in postnatal muscle growth and regeneration.
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Glynnis A
authors.initials: GA
authors.lastname: Garry
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Bezprozvannaya
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Efrain
authors.initials: E
authors.lastname: Sanchez-Ortiz
authors.affiliation: Department of Clinical Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Beibei
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Shelton
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Priscilla
authors.initials: P
authors.lastname: Jaichander
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Rhonda
authors.initials: R
authors.lastname: Bassel-Duby
authors.affiliation: Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
authors.forename: Eric N
authors.initials: EN
authors.lastname: Olson
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D001284:Atrophy; D054715:Cardiotoxins / Q000633:toxicity; D019070:Cell Lineage / Q000187:drug effects; D002469:Cell Separation; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D051379:Mice; D024510:Muscle Development / Q000187:drug effects; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D051763:PAX7 Transcription Factor / Q000378:metabolism; D012038:Regeneration / Q000187:drug effects; D012097:Repressor Proteins / Q000378:metabolism*; D012190:Retroviridae / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D013629:Tamoxifen / Q000494:pharmacology; D051879:Twist-Related Protein 1 / Q000378:metabolism*
chemical_list: D018952:Antigens, CD34; D054715:Cardiotoxins; D051763:PAX7 Transcription Factor; C497322:Pax7 protein, mouse; D012097:Repressor Proteins; D051879:Twist-Related Protein 1; C096852:Twist2 protein, mouse; D013629:Tamoxifen; D009218:Myosins