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Asian Journal of Andrology ; (6): 739-750, 2007.
Artigo em Inglês | WPRIM | ID: wpr-310456

RESUMO

<p><b>AIM</b>To analyze the functional interactions of Cyclin with p53 and Atm in spermatogenesis and DNA double-strand break repair.</p><p><b>METHODS</b>Two lines of double knockout mice were generated. Spermatogenesis and double strand break repair mechanisms were analyzed in Cyclin A1 (Ccna1); p53- and Ccna1; Atm-double knockout mice.</p><p><b>RESULTS</b>The block in spermatogenesis observed in Cyclin A1-/- (Ccna1-/-) testes at the mid-diplotene stage is associated with polynucleated giant cells. We found that Ccna1-deficient testes and especially the giant cells accumulate unrepaired DNA double-strand breaks, as detected by immunohistochemistry for phosphorylated H2AX. In addition, the giant cells escape from apoptosis. The development of giant cells occurred in meiotic prophase I, because testes lacking ATM, which are known to develop spermatogenic arrest earlier than prophase I, do not develop giant cells in the absence of cyclin A1. Cyclin A1 interacted with p53 and phosphorylated p53 in complex with CDK2. Interestingly, p53-deficiency significantly increased the number of giant cells in Ccna1-deficient testes. Gene expression analyses of a panel of DNA repair genes in the mutant testes revealed that none of the genes examined were consistently misregulated in the absence of cyclin A1.</p><p><b>CONCLUSION</b>Ccna1-deficiency in spermatogenesis is associated with defects in DNA double-strand break repair, which is enhanced by loss of p53.</p>


Assuntos
Animais , Masculino , Camundongos , Proteínas Mutadas de Ataxia Telangiectasia , Ciclo Celular , Genética , Fisiologia , Proteínas de Ciclo Celular , Genética , Metabolismo , Ciclina A , Genética , Metabolismo , Ciclina A1 , Ciclina B , Ciclina B2 , DNA , Genética , Reparo do DNA , Genética , Fisiologia , Proteínas de Ligação a DNA , Genética , Metabolismo , Regulação da Expressão Gênica , Genética , Fisiologia , Camundongos Knockout , Proteínas Serina-Treonina Quinases , Genética , Metabolismo , Espermatogênese , Genética , Fisiologia , Testículo , Biologia Celular , Metabolismo , Proteína Supressora de Tumor p53 , Genética , Metabolismo , Proteínas Supressoras de Tumor , Genética , Metabolismo
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