Mammalian BTBD12 (SLX4) protects against genomic instability during mammalian spermatogenesis.
Mammalian BTBD12 (SLX4) protects against genomic instability during mammalian spermatogenesis.
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DOI：
10.1371/journal.pgen.1002094
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发表时间：
2011-06
期刊：
影响因子：
4.5
通讯作者：
Cohen PE
中科院分区：
文献类型：
--
作者：
Holloway JK;Mohan S;Balmus G;Sun X;Modzelewski A;Borst PL;Freire R;Weiss RS;Cohen PE
酵母Slx 4的哺乳动物直系同源物BTBD 12是ATM底物，其充当各种DNA修复活性的支架。在一种新的范可尼贫血亚型患者中报告了人BTBD 12的突变。最近的研究表明，苍蝇和蠕虫的直系同源物，MUS 312和HIM-18，在调节减数分裂交叉所产生的双链断裂（DSB）启动事件，也在减数分裂前的基因组稳定性。利用Btbd 12突变小鼠，我们分析了BTBD 12在哺乳动物配子发生中的作用。BTBD 12定位于野生型雄性的减数分裂前精原细胞和减数分裂精母细胞。btbd 12突变小鼠的正常精子少于15%，生育力低下。胚胎发生过程中BTBD 12的缺失导致原始生殖细胞增殖受损和凋亡增加，从而减少了出生后早期睾丸中的精原细胞池。在前期I，DSB在Btbd 12突变动物中正常启动。然而，DSB修复延迟或受阻，导致持续的γ H2 AX和RAD 51，并且修复途径的选择可能改变，导致粗线处MLH 1/MLH 3病灶数量增加。结果是I期前期及以后的细胞凋亡增加。因此，与酵母Slx 4不同，BTBD 12似乎在减数分裂前期I中起作用，可能在导致产生交换的重组事件期间起作用。与ATM激酶的预期调控一致，Atm−/−雄性小鼠睾丸中的BTBD 12蛋白减少，Btbd 12突变小鼠表现出基因组不稳定性增加，表现为血细胞微核形成增加，与Atm−/−雄性小鼠相似。总之，这些数据表明，BTBD 12的功能，在整个配子发生，以保持基因组的稳定性，可能通过协调修复过程和/或通过连接DNA修复事件的细胞周期通过ATM。减数分裂期间基因组维持所必需的基因突变可导致哺乳动物精子发生的严重破坏和随后的低生育力和/或出生缺陷。酵母Slx 4的哺乳动物同源物BTBD 12在小鼠的体细胞修复中起着关键作用。在这里，我们表明，这一关键功能延伸到哺乳动物生殖细胞，通过检查小鼠中的Btbd 12基因破坏的影响。btbd 12突变小鼠表现出严重的生育能力下降，这是由于减数分裂前精原细胞增殖缺陷和减数分裂进程受损。BTBD 12似乎是导致母本和父本同源染色体之间形成交叉的双链断裂修复事件的正常进展所需的，Btbd 12突变体显示未修复断裂增加，同源染色体相互作用受损，以及交叉中间体数量略有增加。BTBD 12蛋白在Atm敲除小鼠的睾丸中也下调，支持先前的研究表明BTBD 12是ATM激酶的靶标。这些数据提供了关于BTBD 12在哺乳动物配子发生中的作用的新证据，并且对于进一步理解减数分裂DNA修复所涉及的分子过程至关重要。
The mammalian ortholog of yeast Slx4, BTBD12, is an ATM substrate that functions as a scaffold for various DNA repair activities. Mutations of human BTBD12 have been reported in a new sub-type of Fanconi anemia patients. Recent studies have implicated the fly and worm orthologs, MUS312 and HIM-18, in the regulation of meiotic crossovers arising from double-strand break (DSB) initiating events and also in genome stability prior to meiosis. Using a Btbd12 mutant mouse, we analyzed the role of BTBD12 in mammalian gametogenesis. BTBD12 localizes to pre-meiotic spermatogonia and to meiotic spermatocytes in wildtype males. Btbd12 mutant mice have less than 15% normal spermatozoa and are subfertile. Loss of BTBD12 during embryogenesis results in impaired primordial germ cell proliferation and increased apoptosis, which reduces the spermatogonial pool in the early postnatal testis. During prophase I, DSBs initiate normally in Btbd12 mutant animals. However, DSB repair is delayed or impeded, resulting in persistent γH2AX and RAD51, and the choice of repair pathway may be altered, resulting in elevated MLH1/MLH3 focus numbers at pachynema. The result is an increase in apoptosis through prophase I and beyond. Unlike yeast Slx4, therefore, BTBD12 appears to function in meiotic prophase I, possibly during the recombination events that lead to the production of crossovers. In line with its expected regulation by ATM kinase, BTBD12 protein is reduced in the testis of Atm−/− males, and Btbd12 mutant mice exhibit increased genomic instability in the form of elevated blood cell micronucleus formation similar to that seen in Atm−/− males. Taken together, these data indicate that BTBD12 functions throughout gametogenesis to maintain genome stability, possibly by co-ordinating repair processes and/or by linking DNA repair events to the cell cycle via ATM. Mutations in genes essential for genome maintenance during meiosis can result in severe disruptions to spermatogenesis and subsequent low fertility and/or birth defects in mammals. The mammalian homolog of yeast Slx4, BTBD12, plays a critical role in somatic cell repair in mice. Here, we show that this critical function extends to mammalian germ cells, by examining the effects of a Btbd12 gene disruption in mice. Btbd12 mutant mice show severely reduced fertility, as a result of both pre-meiotic spermatogonial proliferation defects and impairment of proper meiotic progression. BTBD12 appears to be required for normal progression of double-strand break repair events that result in the formation of crossovers between maternal and paternal homologous chromosomes, with Btbd12 mutants displaying an increase in unrepaired breaks, impaired homologous chromosome interactions, and a slight increase in the number of crossover intermediates. BTBD12 protein is also down-regulated in the testes of Atm null mice, supporting previous studies showing that BTBD12 is a target of ATM kinase. These data provide new evidence about the role of BTBD12 in mammalian gametogenesis and are critical to furthering the understanding of the molecular processes involved in meiotic DNA repair.
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影响因子：
4.5
作者：
Holloway JK;Booth J;Edelmann W;McGowan CH;Cohen PE
通讯作者：
Cohen PE
影响因子：
10.5
作者：
Fricke, WM;Brill, SJ
通讯作者：
Brill, SJ
影响因子：
64.5
作者：
Fekairi S;Scaglione S;Chahwan C;Taylor ER;Tissier A;Coulon S;Dong MQ;Ruse C;Yates JR 3rd;Russell P;Fuchs RP;McGowan CH;Gaillard PHL
通讯作者：
Gaillard PHL
影响因子：
4.5
作者：
Barchi M;Roig I;Di Giacomo M;de Rooij DG;Keeney S;Jasin M
通讯作者：
Jasin M
DOI：
10.1083/jcb.200909048
发表时间：
2010-03-22
期刊：
The Journal of cell biology
影响因子：
--
作者：
Holloway JK;Morelli MA;Borst PL;Cohen PE
通讯作者：
Cohen PE