Transcription-coupled repair and its deficiency

转录偶联修复及其缺陷

• 批准号: 09044304
• 负责人: TANAKA Kiyoji
• 金额: $ 4.03万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09044304/
• 关键词: DNA repair; trascription; xeroderma pigmentosum; Cockayne syndrome; microinjection; ultraviolet light; skin cancer; gene targeting; 基本転写; 突然変異; アルキル化剤; ノックアウトマウス; 免疫グロブリン

Nucleotide excision repair (NER) removes a wide variety of lesions from the genome and is defective in the genetic disorders xeroderma pigmentosum (XP) and Cockayne syndrome (CS). Complementation studies revealed that 7 genes are involved in XP (XPA-XPG) and 2 in CS (CSA, CSB). There are two subpathways in NER : transcription-coupled (TC-)NER accomplishing efficient removal of lesions blocking transcription and the slower global genome (GG-)NER.(1) We recently discovered a novel 855-amino acid protein, XAB2 (XPA-binding protein 2), containing 18 tetratricopeptide repeats, by virtue of its ability to interact with XPA in yeast two hybrid system. Immunoprecipitation analysis demonstrated that XAB2 is associated with the TC-NER-specific proteins CSA, CSB and RNA polymerase II in vivo. Antibodies against XAB2 inhibited both TCR and transcription when microinjected into living fibroblasts. These results indicate that XAB2 is a novel component involved in TC-NER and transcription. (2) XPA- o … More r CSB-deflcient mice were generated. A very important discovery was made when XPA-deficient micethat develop normally was crossed with the CSB-deflcient mice to generate double knockout mice. The double knockout mice appear to exhibit very severe synergistic developmental impairment resulting in extremely early ceasing of developmenta and death 4-6 weeks after birth. These results indicate that CSB and XPA belong to the different epistatic groups and that DNA damage and transcriptional competance contribute to the process of aging. (3) To find out whether NER contributes to preferential removal of 06-EtGua from active genes (asobserved in mammary cells of the rat and thymus cells of the mouse) repair kinetics for this a dduct have been measured in DNA from different tissues of EtNU-exposed XPA +/- and XPA -/- mice. For tissue-specific global repair of 06-EtGua no significant differences were observed between XPA knock out and heterozygote mice. However, this lesion was removed 3-4 times faster from active genes than from total genomic DNA in liver and brain cells of XPA +/- animals. This preferential repair was not observed in the XPA knock out mice. These results indicate that 06-EtGua in the active gene is repaired by NER. Less

核苷酸切除修复（NER）从基因组中去除各种各样的病变，并且在遗传性疾病着色性干皮病（XP）和Cockayne综合征（CS）中是有缺陷的。互补序列分析表明，XP基因中有7个（XPA-XPG），CS基因中有2个（CSA，CSB）。NER中有两个子途径：转录偶联（TC-）NER实现有效去除阻断转录的病变和较慢的全局基因组（GG-）NER。(1)我们最近在酵母双杂交系统中发现了一个新的XPA结合蛋白XAB 2（XPA binding protein 2），它含有18个三肽重复序列，由855个氨基酸组成。免疫沉淀分析表明，XAB 2与TC-NER特异性蛋白CSA，CSB和RNA聚合酶II在体内。当显微注射到活的成纤维细胞中时，抗XAB 2的抗体抑制TCR和转录。这些结果表明，XAB 2是一个新的组件参与TC-NER和转录。(2)XPA- o ...更多信息 制备CSB缺乏小鼠。当发育正常的XPA缺陷小鼠与CSB缺陷小鼠杂交产生双敲除小鼠时，有了一个非常重要的发现。双基因敲除小鼠似乎表现出非常严重的协同发育障碍，导致极早的发育停止和出生后4-6周的死亡。这些结果表明，CSB和XPA属于不同的上位性类群，DNA损伤和转录竞争参与了衰老过程。(3)为了发现NER是否有助于从活性基因中优先去除06-EtGua（如在大鼠的乳腺细胞和小鼠的胸腺细胞中观察到的），已经在来自EtNU暴露的XPA +/-和XPA -/-小鼠的不同组织的DNA中测量了该产物的修复动力学。对于06-EtGua的组织特异性整体修复，在XPA敲除小鼠和杂合子小鼠之间没有观察到显著差异。然而，在XPA +/-动物的肝和脑细胞中，这种病变从活性基因中去除的速度比从总基因组DNA中快3-4倍。在XPA敲除小鼠中未观察到这种优先修复。这些结果表明，活性基因中的06-EtGua被NER修复。少

项目成果

Ikegami, T., Kuraoka, L., Saijo, M., Kodo, N., Y.Kyogoku, Morikawa, K., Tanaka, K., & Shirakawa, M.: "Solution structure of the DNA- and RPA-binding domain of the human repair factor XPA." Nature Structural Biology. 5. 701-706 (1998)

池上，T.，仓冈，L.，西条，M.，Kodo，N.，Y.Kyogoku，森川，K.，田中，K.，

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Sugasawa, K. 等人：“Xeroderma有色素组C蛋白复合物是全基因组核苷酸切除修复的起始点。”

Sugasawa, K., et al.: "Xeroderma pigmentosum group C protein complex is the initiator of global genome nucleotide excision repair," Mol.Cell. 2. 223-232 (1998)

Sugasawa, K. 等人：“色素性干皮病 C 组蛋白复合物是全基因组核苷酸切除修复的引发剂”，Mol.Cell。

Sugasawa, K., Ng, J.M.Y., Masutani, C., Iwai, S., van der Spek, P., Eker, A.P.M., Hanaoka, F., Bootsma, D., and Hoeijimakers, J.H.J.: "Xeroderma pigmentosum group C protein complex is the initiator of global gnome nucleotide excision repair." Mol.Cell. 2.

Sugasawa, K.、Ng, J.M.Y.、Masutani, C.、Iwai, S.、van der Spek, P.、Eker, A.P.M.、Hanaoka, F.、Bootsma, D. 和 Hoeijimakers, J.H.J.：“着色性干皮病 C 组

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