Radiation-induced delayed cell death in a hypomorphic Artemis cell line
Radiation-induced delayed cell death in a hypomorphic Artemis cell line
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DOI：
10.1093/hmg/ddl050
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发表时间：
2006-04-15
影响因子：
3.5
通讯作者：
Jeggo, PA
中科院分区：
文献类型：
--
作者：
Evans, PM;Woodbine, L;Jeggo, PA
Artemis的零突变导致一种被描述为RS-SCID的情况，在这种情况下，患者表现出放射敏感性并伴有严重的联合免疫缺陷。在这里，我们描述了一位表现为进行性联合免疫缺陷(CID)和淋巴细胞凋亡率升高的患者的Artemis缺陷。患者是两个等位基因都有新突变的复合杂合子，导致Artemis蛋白L70缺失或G126D替换。这两种突变都会影响Artemis的功能，来自患者的成纤维细胞系(F96-224)极大地减少了Artemis的蛋白。Artemis零细胞株不能修复电离辐射引起的DNA双链断裂(DSB)的一个子集，而F96-224细胞表现出缓慢但残留的DSB重新连接。尽管F96-224细胞表现出中等的细胞和临床特征，但它与Artemis空细胞系一样对辐射敏感。我们开发了一种基于流式细胞仪的检测方法，用于检测暴露于电离辐射(2和4GY)后10天的细胞分裂和细胞特性。这一分析表明，与Artemis空细胞系的快速生长停滞相比，F96-224细胞表现出延迟的细胞死亡，并且出现了由对照株显示的周期群体。与对照细胞相比，F96-224细胞的染色体畸变率也升高。因此，F96-224代表了亚形细胞系的一种新的表型。我们认为延迟性细胞死亡与Artemis患者进行性CID表型有关。
Null mutations in Artemis confer a condition described as RS-SCID, in which patients display radiosensitivity combined with severe combined immunodeficiency. Here, we characterize the defect in Artemis in a patient who displayed progressive combined immunodeficiency (CID) and elevated lymphocyte apoptosis. The patient is a compound heterozygote with novel mutations in both alleles, resulting in Artemis proteins with either L70 deletion or G126D substitution. Both mutational changes impact upon Artemis function and a fibroblast cell line derived from the patient (F96-224) has greatly reduced Artemis protein. In contrast to Artemis null cell lines, which fail to repair a subset of DNA double strand breaks (DSBs) induced by ionizing radiation, F96-224 cells show slow but residual DSB rejoining. Despite showing intermediate cellular and clinical features, F96-224 cells are as radiosensitive as Artemis null cell lines. We developed a FACS-based assay to examine cell division and cellular characteristics for 10 days following exposure to ionizing radiation (2 and 4 Gy). This analysis demonstrated that F96-224 cells show delayed cell death when compared with rapid growth arrest of an Artemis null cell line, and the emergence of a cycling population shown by a control line. F96-224 cells also display elevated chromosome aberrations when compared with control cells. F96-224 therefore represents a novel phenotype for a hypomorphic cell line. We suggest that delayed cell death contributes to the progressive CID phenotype of the Artemis patient.