Aging stem cells lose the capacity to properly respond to injury and regenerate their residing tissues. Here, we utilized the ability of Drosophila melanogaster germline stem cells (GSCs) to survive exposure to low doses of ionizing radiation (IR) as a model of adult stem cell injury and identified a regeneration defect in aging GSCs: while aging GSCs survive exposure to IR, they fail to reenter the cell cycle and regenerate the germline in a timely manner. Mechanistically, we identify foxo and mTOR homologue, Tor as important regulators of GSC quiescence following exposure to ionizing radiation. foxo is required for entry in quiescence, while Tor is essential for cell cycle reentry. Importantly, we further show that the lack of regeneration in aging germ line stem cells after IR can be rescued by loss of foxo.

中文翻译：

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Foxo 的缺失挽救了果蝇生殖系中的干细胞衰老

老化的干细胞失去了对损伤做出正确反应和再生其驻留组织的能力。在这里，我们利用黑腹果蝇生殖系干细胞 (GSC) 在低剂量电离辐射 (IR) 下存活的能力作为成体干细胞损伤模型，并确定了老化 GSC 的再生缺陷：而老化 GSC 在暴露于低剂量电离辐射 (IR) 时存活下来IR，它们未能及时重新进入细胞周期并再生生殖系。从机制上讲，我们将 Foxo 和 mTOR 同系物 Tor 确定为暴露于电离辐射后 GSC 静止的重要调节剂。Foxo 是进入静止状态所必需的，而 Tor 是细胞周期再进入所必需的。重要的是，我们进一步表明，IR 后衰老生殖系干细胞缺乏再生可以通过 Foxo 的丢失来挽救。