Genetic probing of homologous recombination and non-homologous end joining during meiotic prophase in irradiated mouse spermatocytes
Genetic probing of homologous recombination and non-homologous end joining during meiotic prophase in irradiated mouse spermatocytes
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DOI：
10.1016/j.mrfmmm.2010.02.004
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发表时间：
2010-06-01
影响因子：
2.3
通讯作者：
de Boer, Peter
中科院分区：
文献类型：
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作者：
Ahmed, Emad A.;Philippens, Marielle E. P.;de Boer, Peter
本研究旨在更好地了解同源重组 (HR) 和非同源末端连接 (NHEJ) 对第一次减数分裂前期辐射诱导的 DNA 双链断裂 (DSB) 修复的相对贡献。对已完成交换的早期和晚期粗线期以及早期双线期精母细胞进行取样。我们研究了 HR 缺陷小鼠和 NHEJ 缺陷小鼠照射后 γ-H2AX 染色质焦点去除的动力学。分析未照射的 RAD54/RAD54B 缺陷精母细胞中的 γ-H2AX 信号表明，由于后期初级精母细胞中 γ-H2AX 焦点显着增加，减数分裂重组修复不完全。在这些小鼠中，照射后 8 小时，早期粗线期精母细胞结果表明，与野生型的 82% 相比，gamma-H2AX 病灶的数量减少了 52%，差异显着。然而，在交叉后（粗线期晚期和双线期早期），没有观察到RAD54/RAD54B缺陷对辐射诱导病灶减少的影响。在NHEJ缺陷的SCID小鼠中，早期精母细胞的修复动力学与野生型小鼠相似。然而，照射后1小时，粗线期晚期和双线期早期精母细胞中发现的病灶比野生型小鼠多1.7倍。这种差异可能与 SCID 小鼠缺乏 DNA-PKcs 依赖性快速修复成分有关。由于随后的修复正常，HR 可能正在接管 综合来看，在 RAD54/RAD54B 缺陷小鼠和 SCID 小鼠中获得的结果表明早期粗线期精母细胞中的 DSB 修复主要通过 HR 进行。 (C) 2010 Elsevier B V 保留所有权利。
This study was designed to obtain a better insight into the relative contribution of homologous recombination (HR) and non-homologous end joining (NHEJ) to the repair of radiation-Induced DNA double-strand breaks (DSBs) at first meiotic prophase. Early and late pachytene and early diplotene spermatocytes that had completed crossing over were sampled. We studied the kinetics of gamma-H2AX chromatin foci removal after irradiation of mice deficient for HR and mice deficient for NHEJ Analyzing gamma-H2AX signals in unirradiated RAD54/RAD54B deficient spermatocytes indicated Incomplete meiotic recombination repair due to the pronounced increase of gamma-H2AX foci in late prophase primary spermatocytes In these mice, 8 h after irradiation, early pachytene spermatocytes showed a reduction of the numbers of gamma-H2AX foci by 52% compared to 82% in the wild type, the difference being significant. However, after crossing over (In late pachytene and early diplotene), no effect of RAD54/RAD54B deficiency on the reduction of irradiation-induced foci was observed In NHEJ deficient SCID mice, repair kinetics in early spermatocytes were similar to those in wild type mice However, 1 h after irradiation in late pachytene and early diplotene spermatocytes 1.7 times more foci were found than in wild type mice. This difference might be related to the absence of a DNA-PKcs dependent fast repair component in SCID mice. As subsequent repair is normal, HR likely is taking over Taken together, the results obtained in RAD54/RAD54B deficient mice and in SCID mice indicate that DSB repair in early pachytene spermatocytes is mainly carried out through HR In late spermatocytes (late pachytenes and early diplotenes) NHEJ is active However, probably there is an interplay between these repair pathways and when in late spermatocytes the NHEJ pathway is compromised HR may take over (C) 2010 Elsevier B V All rights reserved.