The two activation domains of the CCAAT-binding factor CBF interact with the dTAFII110 component of the Drosophila TFIID complex
The two activation domains of the CCAAT-binding factor CBF interact with the dTAFII110 component of the Drosophila TFIID complex
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DOI：
10.1042/bj3310291
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发表时间：
1998-04-01
影响因子：
4.1
通讯作者：
de Crombrugghe, B
中科院分区：
文献类型：
--
作者：
Coustry, F;Sinha, S;de Crombrugghe, B
CCAAT结合因子CBF是一种异源三聚体转录因子，能与许多真核基因中的CCAAT序列特异性结合。以往的研究表明，CBF含有两个转录激活区域：CBF-B亚基中的富含谷氨酰胺、丝氨酸-苏氨酸的区域和CBF-C亚基中的富含谷氨酰胺的区域。在本研究中，我们利用CBF-B和CBF-C在体外转录实验中的一系列缺失突变，进一步描述了这些区域中足以支持CBF转录激活的较小片段。为了测试CBF激活转录是否需要共激活剂，我们研究了CBF和dTAF110之间的相互作用，dTAF110是果蝇TFIID复合体的一个成分。最近的工作表明，SPL转录因子的富含谷氨酰胺的区域与dTAF110相互作用，这种相互作用在介导转录激活中起着重要作用。在这里，我们首先在体外的直接相互作用实验中证明了CBF与dTAF110结合。通过酵母双杂交系统，我们发现CBF的两个转录激活结构域都与dTAF110相互作用。缺失分析表明，转录激活所需的CBF-B片段也参与了与dTAF110的相互作用。在CBF-C中，分子的C-末端似乎是这两种活动所必需的。我们的结果表明，TAF110可能是CBF介导转录激活的辅助激活因子之一。
The CCAAT-binding factor CBF is a heterotrimeric transcription factor that specifically binds to CCAAT sequences in many eukaryotic genes. Previous studies have shown that CBF contains two transcription activation domains: a glutamine-rich, serine-threonine-rich domain present in the CBF-B subunit and a glutamine-rich domain in the CBF-C subunit, In this study, by using a series of deletion mutations of CBF-B and CBF-C in transcription assay in vitro, we further delineated smaller segments in these domains that were sufficient to support transcriptional activation by CBF. To test whether transcription activation by CBF requires co-activators, we examined the interaction between CBF and dTAF110, a component of the Drosophila TFIID complex. Recent work has demonstrated that glutamine-rich domains of the Spl transcription factor interact with dTAF110 and that this interaction has an important role in mediating transcription activation. Here we first demonstrate in a direct interaction assay in vitro that CBF binds dTAF110. By using a yeast two-hybrid system we show that both of the transcription activation domains of CBF interact with dTAF110. A deletion analysis suggests that a segment of CBF-B needed for transcription activation is also involved in interaction with dTAF110. In CBF-C the C-terminal portion of the molecule seems to be needed for these two activities. Our results suggest that TAF110 might represent one of the co-activators that mediate transcriptional activation by CBF.