The dTAFII80 subunit of Drosophila TFIID contains β-transducin repeats-猫眼课题宝

果蝇 TFIID 的 dTAFII80 亚基包含 β-转导蛋白重复序列

DOI：

发表时间：

1993

期刊：

Nature

影响因子：

64.8

通讯作者：

中科院分区：

综合性期刊1区

文献类型：

作者：

B. Dynlacht;R. Weinzierl;A. Admon;R. Tjian

RNA聚合酶II转录装置TFIID的一个关键组成部分是一个多蛋白复合物，包含TATA盒结合蛋白（TBP）和至少7个紧密相关因子（TAFs）1,2。虽然大多数TFIID亚基的功能尚不清楚，但很明显，TAFs不是基础活性所必需的，而是调节转录所必需的一个或多个，因此充当辅激活因子1 - 4。多个亚基的存在表明存在一个复杂的组装过程，并且taf可能负责其他活动。我们已经描述了亚基dTAFII110的性质，它可以直接与转录激活子Sp1相互作用（参考文献5）。此外，最大的亚基dTAFII250直接与TBP结合，并将其他TAFs连接到该复合物6。本文描述了果蝇TAF基因Mr 80000， dTAFII80的克隆、表达和部分特性。序列分析显示，dTAFII80含有多个WD40 （β-转导素）重复序列7拷贝。此外，dTAFII80与拟南芥基因COP1具有扩展序列相似性，COP1编码一种被认为调节发育的转录因子8。我们已经表达了重组dTAFII80，并开始表征其与TFIID复合体其他成员的相互作用。纯化的重组dTAFII80不能直接结合TBP，也不能与dTAFII250的c端结构域强相互作用（Δ250）。相反，dTAFII80只能识别含有TBP、Δ250、110和60的高阶复合物并与之相互作用。这些发现表明，TFIID的形成可能需要TAFs的有序组装，其中一些直接与TBP结合，而另一些则作为特定的TAF/TAF相互作用的结果被拴在复合物上。

A KEY component of the RNA polymerase II transcriptional apparatus, TFIID, is a multi-protein complex containing the TATA box-binding protein (TBP) and at least seven tightly associated factors (TAFs)1,2. Although the functions of most TFIID subunits are unknown, it is clear that TAFs are not necessary for basal activity but that one or more are required for regulated transcription, and so behave as coactivators1–4. The presence of multiple subunits indicates that there is an intricate assembly process and that TAFs may be responsible for other activities. We have described the properties of the subunit dTAFII110, which can interact directly with the transcriptional activator Sp1 (ref. 5). In addition, the largest subunit, dTAFII250, binds directly to TBP and links other TAFs to the complex6. Here we describe the cloning, expression and partial characterization of the Drosophila TAF of Mr 80,000, dTAFII80. Sequence analysis reveals that dTAFII80 contains several copies of the WD40 (β-transducin) repeat7. Moreover, dTAFII80 shares extended sequence similarity with an Arabidopsis gene, COP1, which encodes a putative transcription factor that is thought to regulate development8. We have expressed recombinant dTAFII80 and begun to characterize its interaction with other members of the TFIID complex. Purified recombinant dTAFII80 is unable to bind TBP directly or to interact strongly with the C-terminal domain of dTAFII250 (Δ250). Instead, dTAFII80 is only able to recognize and interact with a higher-order complex containing TBP, Δ250, 110 and 60. These findings suggest the formation of TFIID may require an ordered assembly of the TAFs, some of which bind directly to TBP and others that are tethered to the complex as a result of specific TAF/TAF interactions.