Functional Comparison of XPF Missense Mutations Associated to Multiple DNA Repair Disorders
Functional Comparison of XPF Missense Mutations Associated to Multiple DNA Repair Disorders
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DOI：
10.3390/genes10010060
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发表时间：
2019-01
期刊：
影响因子：
3.5
通讯作者：
Maria Marín;M. Ramírez;M. A. Carmona;Nan Jia;T. Ogi;M. Bogliolo;J. Surrallés
中科院分区：
文献类型：
--
作者：
Maria Marín;M. Ramírez;M. A. Carmona;Nan Jia;T. Ogi;M. Bogliolo;J. Surrallés
XPF 核酸内切酶是最重要的 DNA 修复蛋白之一。 XPF 由 XPF/ERCC4 编码，提供 XPF-ERCC1 异二聚体的酶活性，XPF-ERCC1 异二聚体是一种核酸内切酶，可在各种 DNA 损伤的 5' 侧进行切割。 XPF 对于核苷酸切除修复 (NER) 和链间交联修复 (ICLR) 至关重要。 XPF/ERCC4 突变与多种人类疾病相关：色素性干皮病 (XP)、节段性早衰症 (XFE)、范可尼贫血 (FA)、科凯恩综合征 (CS) 和 XP/CS 联合疾病 (XPCSCD)。大多数受影响的个体是 XPF/ERCC4 突变的复合杂合子，使基因型/表型相关性的识别变得复杂。我们报告了表达六种疾病特异性致病性 XPF 氨基酸取代突变的人 XPF-KO（敲除）同基因细胞中的 NER 和 ICLR 功能研究的详细概述。紫外线 (UV) 敏感性和非计划 DNA 合成 (UDS) 检测提供了最可靠的信息，可区分与 ICLR 损伤相关的突变和与 NER 缺陷相关的突变，而 RNA 合成 (RRS) 检测的恢复结果暗示 XPF 在解决 R 环中可能发挥的作用。我们的功能研究表明，确定的细胞表型不能轻易与每个 XPF 突变相关联。 XPF 序列上的取代位置不能预测细胞表型，也不能反映特定疾病。因此，除了突变类型之外，等位基因相互作用、蛋白质稳定性和突变蛋白的细胞内分布也可能有助于改变DNA修复途径的平衡，从而导致临床上不同的疾病。
XPF endonuclease is one of the most important DNA repair proteins. Encoded by XPF/ERCC4, XPF provides the enzymatic activity of XPF-ERCC1 heterodimer, an endonuclease that incises at the 5’ side of various DNA lesions. XPF is essential for nucleotide excision repair (NER) and interstrand crosslink repair (ICLR). XPF/ERCC4 mutations are associated with several human diseases: Xeroderma Pigmentosum (XP), Segmental Progeria (XFE), Fanconi Anemia (FA), Cockayne Syndrome (CS), and XP/CS combined disease (XPCSCD). Most affected individuals are compound heterozygotes for XPF/ERCC4 mutations complicating the identification of genotype/phenotype correlations. We report a detailed overview of NER and ICLR functional studies in human XPF-KO (knock-out) isogenic cells expressing six disease-specific pathogenic XPF amino acid substitution mutations. Ultraviolet (UV) sensitivity and unscheduled DNA synthesis (UDS) assays provide the most reliable information to discern mutations associated with ICLR impairment from mutations related to NER deficiency, whereas recovery of RNA synthesis (RRS) assays results hint to a possible role of XPF in resolving R-loops. Our functional studies demonstrate that a defined cellular phenotype cannot be easily correlated to each XPF mutation. Substituted positions along XPF sequences are not predictive of cellular phenotype nor reflect a particular disease. Therefore, in addition to mutation type, allelic interactions, protein stability and intracellular distribution of mutant proteins may also contribute to alter DNA repair pathways balance leading to clinically distinct disorders.