KU AUTOANTIGEN IS THE REGULATORY COMPONENT OF A TEMPLATE-ASSOCIATED PROTEIN-KINASE THAT PHOSPHORYLATES RNA POLYMERASE-II
KU AUTOANTIGEN IS THE REGULATORY COMPONENT OF A TEMPLATE-ASSOCIATED PROTEIN-KINASE THAT PHOSPHORYLATES RNA POLYMERASE-II
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DOI：
10.1073/pnas.89.24.11920
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发表时间：
1992-12-15
影响因子：
11.1
通讯作者：
DYNAN, WS
中科院分区：
文献类型：
--
作者：
DVIR, A;PETERSON, SR;DYNAN, WS
RNA聚合酶II的羧基末端结构域含有串联重复的七肽序列。先前的工作表明，该序列在多个位点被模板相关蛋白激酶磷酸化，该反应与RNA合成的起始密切相关。我们已经从人（HeLa）细胞中纯化了这种激酶，使其具有明显的同质性。纯化的激酶仅在DNA和一般转录因子TFIID（TBP）、TFIIB和TFIIF存在下磷酸化天然RNA聚合酶II。完全活性需要两种激酶组分：催化组分和DNA结合调节组分。根据其组分多肽的分子量、其DNA结合特性及其与抗Ku单克隆抗体的反应性，已将调节组分鉴定为Ku自身抗原。Ku自身抗原将激酶的催化组分募集到模板。Ku自身抗原先前已被提出通过特征性的结合和滑动机制与DNA相互作用。这种相互作用模式可以提供一种机制，使激酶靶向转录复合物和其他DNA结合的底物。
The carboxyl-terminal domain of RNA polymerase II contains a tandemly repeated heptapeptide sequence. Previous work has shown that this sequence is phosphorylated at multiple sites by a template-associated protein kinase, in a reaction that is closely associated with the initiation of RNA synthesis. We have purified this kinase to apparent homogeneity from human (HeLa) cells. The purified kinase phosphorylates native RNA polymerase II only in the presence of DNA and the general transcription factors TFIID (TBP), TFIIB, and TFIIF. Two kinase components are required for full activity: a catalytic component and a DNA-binding regulatory component. The regulatory component has been identified as Ku autoantigen, based on the molecular weights of its component polypeptides, its DNA-binding properties, and its reactivity with anti-Ku monoclonal antibodies. The Ku autoantigen recruits the catalytic component of the kinase to the template. Ku autoantigen has been previously proposed to interact with DNA by a characteristic bind-and-slide mechanism. This mode of interaction may provide a mechanism for targeting the kinase to the transcription complex and other DNA-bound substrates.