Gamma-ray irradiation promotes premature meiosis of spontaneously differentiating testis-ova in the testis of p53-deficient medaka (Oryzias latipes).
Gamma-ray irradiation promotes premature meiosis of spontaneously differentiating testis-ova in the testis of p53-deficient medaka (Oryzias latipes).
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DOI：
10.1038/cddis.2012.133
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发表时间：
2012-10-04
影响因子：
9
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在本研究中，通过 RT-PCR 或原位杂交分析组织学变化以及 42Sp50、Oct 4 和卵黄原蛋白 (VTG2) 的基因表达，研究 p53 在 p53 缺陷的青鳉雄性生精细胞受损中的作用。我们发现，在p53缺陷的睾丸中，少量卵母细胞样细胞（睾丸-卵子）在A型和早期B型精原细胞的囊肿中自发分化，而野生型（wt）睾丸中从未发现睾丸-卵子。此外，电离辐射（IR）照射增加了p53缺陷睾丸中睾丸-卵子的数量，增加了睾丸-卵子的大小，并在照射后14天内进入过早减数分裂的合子期或粗线期阶段。然而，照射后 28 天，几乎所有的睾丸卵子都被 p53 独立的细胞凋亡消除，精子发生完全恢复。在wt睾丸中，IR从未诱导睾丸-卵子分化。这是第一项证明p53基因在消除睾丸中自发睾丸-卵子中的关键作用的研究，并且p53对于受损睾丸中精子发生的恢复并不是必不可少的，在受损睾丸中，细胞周期调节受到红外线辐射的干扰。
In this study, the roles of p53 in impaired spermatogenic male germ cells of p53-deficient medaka were investigated by analyzing histological changes, and gene expressions of 42Sp50, Oct 4 and vitellogenin (VTG2) by RT-PCR or in situ hybridization in the testes. We found that a small number of oocyte-like cells (testis–ova) differentiated spontaneously in the cysts of type A and early type B spermatogonia in the p53-deficient testes, in contrast to the wild-type (wt) testes in which testis–ova were never found. Furthermore, ionizing radiation (IR) irradiation increased the number of testis–ova in p53-deficient testes, increased testis–ova size and proceeded up to the zygotene or pachytene stages of premature meiosis within 14 days after irradiation. However, 28 days after irradiation, almost all the testis–ova were eliminated presumably by p53-independent apoptosis, and spermatogenesis was restored completely. In the wt testis, IR never induced testis–ova differentiation. This is the first study to demonstrate the pivotal role of the p53 gene in the elimination of spontaneous testis–ova in testes, and that p53 is not indispensable for the restoration of spermatogenesis in the impaired testes in which cell cycle regulation is disturbed by IR irradiation.