BLM is an early responder to DNA double-strand breaks
BLM is an early responder to DNA double-strand breaks
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DOI：
10.1016/j.bbrc.2006.07.037
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发表时间：
2006-09-15
影响因子：
3.1
通讯作者：
Enomoto, Takemi
中科院分区：
文献类型：
--
作者：
Karmakar, Parimal;Seki, Masayuki;Enomoto, Takemi
Bloom综合征(BS)是一种常染色体隐性遗传病，以明显的癌症易感性和基因组不稳定性增加为特征。BS中的缺陷蛋白BLm是RecQ解旋酶家族的成员，被认为在各种DNA交易中发挥功能，包括复制、修复和重组。在这里，我们证明了内源性和过表达的人类BLM都在激光诱导的DNA双链断裂的位置积累在10s内，并与Gamma、H2AX和ATM共定位。与其RecQ解旋酶家族成员WRN一样，Werner综合征中的缺陷蛋白WRN对BLM蛋白的剖析表明，其HRDC结构域足以使其募集到受损部位。此外，我们还证实了HRDC结构域内跨越1250-1292氨基酸的C末端区域是BLM招募所必需的。为了确定BLM募集所需的其他蛋白质，我们检测了从鸡DT40细胞产生的各种突变体中BLM的募集情况，发现BLM的早期积累并不依赖于ATM、RAD17、DNA-PKcs、NBS1、XRCC3、RAD52、RAD54或WRN的存在。因此，DNA解旋酶中的HRDC结构域是DNA双链断裂的常见早期反应，使BLM和WRN参与DNA修复。(C)2006 Elsevier Inc.保留所有权利。
Bloom syndrome (BS) is an autosomal recessive disorder characterized by a marked predisposition to cancer and elevated genomic instability. The defective protein in BS, BLM, is a member of the RecQ helicase family and is believed to function in various DNA transactions, including in replication, repair, and recombination. Here, we show that both endogenous and overexpressed human BLM accumulates at sites of laser light-induced DNA double-strand breaks within 10s and colocalizes with gamma H2AX and ATM. Like its RecQ helicase family member, WRN, the defective protein in Werner syndrome, dissection of the BLM protein revealed that its HRDC domain is sufficient for its recruitment to the damaged sites. In addition, we confirmed that the C-terminal region spanning amino acids 1250-1292 within the HRDC domain is necessary for BLM recruitment. To identify additional proteins required for the recruitment of BLM, we examined the recruitment of BLM in various mutants generated from chicken DT40 cells and found that the early accumulation of BLM was not dependent on the presence of ATM, RAD17, DNA-PKcs, NBS1, XRCC3, RAD52, RAD54, or WRN. Thus, HRDC domain in DNA helicases is a common early responder to DNA double-strand breaks, enabling BLM and WRN to be involved in DNA repair. (c) 2006 Elsevier Inc. All rights reserved.