title: Transient inactivation of Rb and ARF yields regenerative cells from postmitotic mammalian muscle.
abstract: An outstanding biological question is why tissue regeneration in mammals is limited, whereas urodele amphibians and teleost fish regenerate major structures, largely by cell cycle reentry. Upon inactivation of Rb, proliferation of postmitotic urodele skeletal muscle is induced, whereas in mammalian muscle this mechanism does not exist. We postulated that a tumor suppressor present in mammals but absent in regenerative vertebrates, the Ink4a product ARF (alternative reading frame), is a regeneration suppressor. Concomitant inactivation of Arf and Rb led to mammalian muscle cell cycle reentry, loss of differentiation properties, and upregulation of cytokinetic machinery. Single postmitotic myocytes were isolated by laser micro-dissection-catapulting, and transient suppression of Arf and Rb yielded myoblast colonies that retained the ability to differentiate and fuse into myofibers upon transplantation in vivo. These results show that differentiation of mammalian cells is reversed by inactivation of Arf and Rb and support the hypothesis that Arf evolved at the expense of regeneration.
authors.affiliation: Baxter Laboratory for Stem Cell Biology, Department of Microbiology & Immunology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Kostandin V
authors.initials: KV
authors.lastname: Pajcini
authors.forename: Stephane Y
authors.initials: SY
authors.lastname: Corbel
authors.forename: Julien
authors.initials: J
authors.lastname: Sage
authors.forename: Jason H
authors.initials: JH
authors.lastname: Pomerantz
authors.forename: Helen M
authors.initials: HM
authors.lastname: Blau
mesh_terms: D000818:Animals; D054337:Cell Dedifferentiation; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D002999:Clone Cells; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism*; D048749:Cytokinesis; D007834:Lasers; D008322:Mammals / Q000378:metabolism*; D051379:Mice; D042282:Microdissection; D008938:Mitosis; D032342:Muscle Cells / Q000166:cytology / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D009132:Muscles / Q000166:cytology* / Q000378:metabolism*; D011312:Pressure; D034741:RNA, Small Interfering / Q000378:metabolism; D012038:Regeneration / Q000502:physiology*; D016160:Retinoblastoma Protein / Q000378:metabolism*; D016196:S Phase; D044967:Serum; D015854:Up-Regulation
chemical_list: C417743:Cdkn2a protein, mouse; D019941:Cyclin-Dependent Kinase Inhibitor p16; D034741:RNA, Small Interfering; D016160:Retinoblastoma Protein