Mechanism of promoter melting by the xeroderma pigmentosum complementation group B helicase of transcription factor IIH revealed by protein-DNA photo-cross-linking
Mechanism of promoter melting by the xeroderma pigmentosum complementation group B helicase of transcription factor IIH revealed by protein-DNA photo-cross-linking
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DOI：
10.1128/mcb.20.21.8168-8177.2000
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发表时间：
2000-11-01
影响因子：
5.3
通讯作者：
Coulombe, B
中科院分区：
文献类型：
--
作者：
Douziech, M;Coin, F;Coulombe, B
P89/着色性干皮病互补B组(XPB)ATPase-转录因子IIH解旋酶(TFIIH)是RNA聚合酶II(RNA-PII)启动转录前启动子熔化所必需的。通过定点蛋白质-DNA光交联法研究启动子复合体的拓扑结构，我们发现p89/XPB使启动子在起始点的上游和下游接触。上游的接触位于发生启动子熔化的区域(位置-9到+2)，需要紧密的DNA包裹在RNAPII周围。可水解性ATP的加入将位于-5和+1位置的模板链与RNAPII亚基连接。在1例着色性干皮病患者中发现的p89/XPB突变会损害TFIIH与该复合体正确结合的能力，从而融化启动子DNA。
The p89/xeroderma pigmentosum complementation group B (XPB) ATPase-helicase of transcription factor IIH (TFIIH) is essential for promoter melting prior to transcription initiation by RNA polymerase II (RNA-PII). By studying the topological organization of the initiation complex using site-specific protein-DNA photo-cross-linking, we have shown that p89/XPB makes promoter contacts both upstream and downstream of the initiation site. The upstream contact, which is in the region where promoter melting occurs (positions -9 to +2), requires tight DNA wrapping around RNAPII. The addition of hydrolyzable ATP tethers the template strand at positions -5 and +1 to RNAPII subunits. A mutation in p89/XPB found in a xeroderma pigmentosum patient impairs the ability of TFIIH to associate correctly with the complex and thereby melt promoter DNA, A model for open complex formation is proposed.