title: Premeiotic germ cell defect in seminiferous tubules of Atm-null testis.
abstract: Lifelong spermatogenesis is maintained by coordinated sequential processes including self-renewal of stem cells, proliferation of spermatogonial cells, meiotic division, and spermiogenesis. It has been shown that ataxia telangiectasia-mutated (ATM) is required for meiotic division of the seminiferous tubules. Here, we show that, in addition to its role in meiosis, ATM has a pivotal role in premeiotic germ cell maintenance. ATM is activated in premeiotic spermatogonial cells and the Atm-null testis shows progressive degeneration. In Atm-null testicular cells, differing from bone marrow cells of Atm-null mice, reactive oxygen species-mediated p16(Ink4a) activation does not occur in Atm-null premeiotic germ cells, which suggests the involvement of different signaling pathways from bone marrow defects. Although Atm-null bone marrow undergoes p16(Ink4a)-mediated cellular senescence program, Atm-null premeiotic germ cells exhibited cell cycle arrest and apoptotic elimination of premeiotic germ cells, which is different from p16(Ink4a)-mediated senescence.
authors.affiliation: Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582, Japan. keiyot@gmail.com
authors.forename: Keiyo
authors.initials: K
authors.lastname: Takubo
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirao
authors.forename: Masako
authors.initials: M
authors.lastname: Ohmura
authors.forename: Masaki
authors.initials: M
authors.lastname: Azuma
authors.forename: Fumio
authors.initials: F
authors.lastname: Arai
authors.forename: Go
authors.initials: G
authors.lastname: Nagamatsu
authors.forename: Toshio
authors.initials: T
authors.lastname: Suda
mesh_terms: D000818:Animals; D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D016922:Cellular Senescence / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D008297:Male; D008540:Meiosis; D051379:Mice; D008817:Mice, Mutant Strains; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012671:Seminiferous Tubules / Q000166:cytology*; D013091:Spermatogenesis / Q000235:genetics*; D013093:Spermatogonia / Q000166:cytology*; D013737:Testis / Q000166:cytology; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D017382:Reactive Oxygen Species; D025521:Tumor Suppressor Proteins; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases