Genomic instability and enhanced radiosensitivity in Hsp70.1-and Hsp70.3-deficient mice
Genomic instability and enhanced radiosensitivity in Hsp70.1-and Hsp70.3-deficient mice
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DOI：
10.1128/mcb.24.2.899-911.2004
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发表时间：
2004-01-01
影响因子：
5.3
通讯作者：
Pandita, TK
中科院分区：
文献类型：
--
作者：
Hunt, CR;Dix, DJ;Pandita, TK
热休克蛋白（HSPs）在从原核生物到真核生物的所有生物中高度保守。在小鼠中，HSP基因Hsp70.1和Hsp70.3可被内源性和外源性应激源诱导，如热和毒物。为了确定这些蛋白质是否特异性地影响基因组不稳定性，通过基因靶向产生Hsp70.1和Hsp70.3缺陷的小鼠（Hsp70.1/3（-/-）小鼠）。从Hsp70.1/3（-/-）小鼠制备的小鼠胚胎成纤维细胞（MEFs）在热诱导应激后不合成Hsp70.1或Hsp70.3。虽然Hsp70.1/3（-/-）突变小鼠是可生育的，但它们的细胞显示出基因组不稳定性，这种不稳定性通过热处理而增强。来自Hsp70.1/3（-/-）小鼠的细胞也显示出比对照Hsp70.1/3（+/+）细胞更高频率的染色体端对端缔合。为了确定所观察到的基因组不稳定性是否与染色体修复缺陷有关，将Hsp70.1/3（-/-）和Hsp70.1/3（+/+）成纤维细胞单独用电离辐射（IR）或加热和IR处理。（基因组不稳定性的标志）、增加的细胞杀伤和增强的IR诱导的Hsp70.1/3（-/-）细胞中的致癌转化。与Hsp70.1/3（+/+）细胞相比，IR暴露前的热处理增强了Hsp70.1/3（-/-）细胞中的细胞杀伤、S期特异性染色体损伤和转化体的频率。体内和体外研究均首次证明Hsp70.1和Hsp70.3在应激条件下维持基因组稳定性方面具有重要作用。
Heat shock proteins (HSPs) are highly conserved among all organisms from prokaryotes to eukaryotes. In mice, the HSP genes Hsp70.1 and Hsp70.3 are induced by both endogenous and exogenous stressors, such as heat and toxicants. In order to determine whether such proteins specifically influence genomic instability, mice deficient for Hsp70.1 and Hsp70.3 (Hsp70.1/3(-/-) mice) were generated by gene targeting. Mouse embryonic fibroblasts (MEFs) prepared from Hsp70.1/3 (-/-) mice did not synthesize Hsp70.1 or Hsp70.3 after heat-induced stress. While the Hsp70.1/3(-/-) mutant mice were fertile, their cells displayed genomic instability that was enhanced by heat treatment. Cells from Hsp70.1/3(-/-) mice also display a higher frequency of chromosome end-to-end associations than do control Hsp70.1/3(+/+) cells. To determine whether observed genomic instability was related to defective chromosome repair, Hsp70.1/3(-/-) and Hsp70.1/3(+/+) fibroblasts were treated with ionizing radiation (IR) alone or heat and IR. Exposure to IR led to more residual chromosome aberrations, radioresistant DNA synthesis (a hallmark of genomic instability), increased cell killing, and enhanced IR-induced oncogenic transformation in Hsp70.1/3(-/-) cells. Heat treatment prior to IR exposure enhanced cell killing, S-phase-specific chromosome damage, and the frequency of transformants in Hsp70.1/3(-/-) cells in comparison to Hsp70.1/3(+/+) cells. Both in vivo and in vitro studies demonstrate for the first time that Hsp70.1 and Hsp70.3 have an,essential role in maintaining genomic stability under stress conditions.