Fanconi anemia, complementation group A, cells are defective in ability to produce incisions at sites of psoralen interstrand cross-links
Fanconi anemia, complementation group A, cells are defective in ability to produce incisions at sites of psoralen interstrand cross-links
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DOI：
10.1093/carcin/21.4.741
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发表时间：
2000-04-01
期刊：
影响因子：
4.7
通讯作者：
Lambert, MW
中科院分区：
文献类型：
--
作者：
Kumaresan, KR;Lambert, MW
Fanconi贫血，互补组A（FA-A）细胞对产生DNA链间交联的试剂的超敏性与它们修复这种类型的损伤的能力的缺陷相关。为了更清楚地阐明这种修复缺陷，检查了FA-A细胞的染色质相关蛋白提取物在DNA链间交联位点内切核酸产生切口的能力。用由4，5 '，8-三甲基补骨脂素（TMP）加长波长（UVA）光产生的单位点特异性单加合物或链间交联构建确定的140 bp DNA底物。我们的研究结果表明，FA-A细胞在DNA链间交联位点产生双切口的能力是有缺陷的。具体地，在交联的呋喃和吡喃酮侧的3 '-和5'-侧上存在缺陷切口。这种缺陷在用表达FANCA cDNA的逆转录病毒载体转导的FA-A细胞中得到纠正。在TMP单加合物的位点处，FA-A细胞可以在呋喃侧单加合物的3 '和5'侧上引入切口，但是在吡喃酮侧单加合物上产生这些切口的能力有缺陷。这些研究还表明，XPF参与了正常浸提液在这些底物上产生的5'切口。这些结果与我们先前的工作相关，该工作表明FA-A细胞主要在修复磷脂链间交联的能力上有缺陷，在修复磷脂单加合物的能力上有较小的缺陷。在TMP链间交联位点的核酸内切切割缺陷可能与非红细胞a血影蛋白水平降低有关。（α SpII Sigma*）在FA-A细胞提取物中，α SpII Sigma* 可以作为支架排列参与交联修复的蛋白质并增强它们的相互作用;因此，α SpII Sigma* 的缺陷可导致修复效率降低和我们在FA-A细胞中链间交联位点观察到的切口水平降低。
The hypersensitivity of Fanconi anemia, complementation group A, (FA-A) cells to agents which produce DNA interstrand cross-links correlates with a defect in their ability to repair this type of damage. In order to more clearly elucidate this repair defect, chromatin-associated protein extracts from FA-A cells were examined for ability to endonucleolytically produce incisions in DNA at sites of interstrand cross-links. A defined 140 bp DNA substrate was constructed with a single site-specific monoadduct or interstrand cross-link produced by 4,5',8-trimethylpsoralen (TMP) plus long wavelength (UVA) light. Our results show that FA-A cells are defective in ability to produce dual incisions in DNA at sites of interstrand cross-links. Specifically, there is defective incision on the 3'- and 5'-sides of both the furan and pyrone sides of the crosslink. This defect is corrected in FA-A cells transduced with a retroviral vector expressing FANCA cDNA, At the site of a TMP monoadduct, FA-A cells can introduce incisions on both the 3'- and 5'-sides of the furan side monoadduct, but are defective in ability to produce these incisions on the pyrone side monoadduct. These studies also indicate that XPF is involved in production of the 5' incision by the normal extracts on these substrates. These results correlate with our previous work, which showed that FA-A cells are mainly defective in ability to repair psoralen interstrand cross-links with a lesser defect in ability to repair psoralen monoadducts. This defect in endonucleolytic incision at sites of TMP interstrand cross-links could be related to reduced levels of non-erythroid a spectrin (alpha SpII Sigma*) in the extracts from FA-A cells, alpha SpII Sigma* could act as a scaffold to align proteins involved in cross-link repair and enhance their interactions; a deficiency in alpha SpII Sigma* could thus lead to reduced efficiency of repair and the decreased levels of incisions we observe at sites of interstrand cross-links in FA-A cells.