Mechanism of Transcription Control by Drosophila TAF250

描述（由申请人提供）：TAFII 250是10种以上与TFIID中TBP复合的TATA结合蛋白（TBP）相关因子（TAFII）之一。TFIID与基因转录起始位点周围的核心启动子的结合使前起始复合物（PlC）的组装成核，所述前起始复合物（PlC）含有RNA聚合酶II（Pol II）和一般转录因子TFIIA、TFIIB、TFIIE、TFIIF和TFIIH。TFIID的成核功能被认为包括几个不同的事件：（1）核心启动子DNA元件的激活子依赖性识别;（2）有利于PlC组装和转录起始的染色质环境的产生;和（3）GTF的结构和功能修饰以促进PlC组装和转录起始。TAFII 250在体外的活性与TAFII 250在这些TFIID事件中的作用一致，但支持TAFII 250在染色质背景下的这些或其他特定作用的证据不足。我们假设，个别TAFII 250活动发挥基因特异性作用，在RNA聚合酶II转录和信号通路和激活剂利用个别TAFII 250活动，以调节特定基因的转录。因此，在目标1的补助金，我们将使用一个公正的遗传筛选，以确定TAFII 250域和残基是重要的果蝇生存能力。该筛选将使我们能够识别TAFII 250的生物学相关特征。在目标2的补助金，我们将确定是否差异表达或差异染色质协会TAFII 250 C-末端区（CTR）亚型有助于基因特异性转录果蝇和TAFII 250功能是否在目标1中确定有助于这一机制。在目标3的补助金，我们将确定是否差异的生物化学活性TAFII 250 CTR亚型有助于基因特异性转录果蝇和TAFII 250功能是否在目标1中确定有助于这一机制。个体TAFII 250活性如何促进促进体内转录起始的一系列复杂的顺序相互作用和构象变化的确定将导致更好地理解基因表达调节的机制以及该过程中的缺陷如何导致癌症和发育异常。

DESCRIPTION (provided by applicant): TAFII250 is one of more than 10 TATA-binding protein (TBP)-associated factors (TAFIIs) that are complexed with TBP in TFIID. Binding of TFIID to the core promoter surrounding the transcription start site of a gene nucleates assembly of the preinitiation complex (PlC), which contains RNA polymerase II (Pol II) and the general transcription factors TFIIA, TFIIB, TFIIE, TFIIF, and TFIIH. The nucleating function of TFIID is thought to comprise several distinct events: (1) activator-dependent recognition of core promoter DNA elements; (2) the generation of a chromatin environment that is favorable to PlC assembly and transcription initiation; and (3) structural and functional modification of GTFs to facilitate PlC assembly and transcription initiation. Activities attributed to TAFII250 in vitro are consistent with roles for TAFII250 in each of these TFIID events, but evidence supporting these or other specific roles for TAFII250 in the context of chromatin is insufficient. We hypothesize that individual TAFII250 activities play gene-specific roles during RNA Pol II transcription and that signaling pathways and activators utilize individual TAFII250 activities to modulate the transcription of specific genes. Thus, in Aim 1 of the grant, we will use an unbiased genetic screen to identify TAFII250 domains and residues that are important for Drosophila viability. This screen will allow us to identify biologically relevant features of TAFII250. In Aim 2 of the grant, we will determine whether differential expression or differential chromatin association of TAFII250 C-terminal region (CTR) isoforms contributes to gene-specific transcription in Drosophila and whether TAFII250 features identified in Aim 1 contribute to this mechanism. In Aim 3 of the grant, we will determine whether differential biochemical activities of TAFII250 CTR isoforms contribute to gene-specific transcription in Drosophila and whether TAFII250 features identified in Aim 1 contribute to this mechanism. The determination of how individual TAFII250 activities contribute to the complex series of sequential interactions and conformational changes that promote transcription initiation in vivo will lead to a better understanding of mechanisms through which gene expression is regulated and how defects in this process lead to cancer and developmental abnormalities.