The TFIID Complex-Biophysical & Structural Studies

描述(申请人提供)：在真核生物中，基因组中包含的信息的转录是一个严格调控的过程。转录是通过组装成多个复合体的大约40-50个不同的蛋白质组分的协调作用来进行的，这些复合体相互协作识别转录起始点，整合调控信号，并提供合成RNA转录本所需的酶活性。每个基因内部都有控制元件，它们决定了基因转录的方式和时间。对于由RNA聚合酶II转录的蛋白质编码基因，核心启动子和基础机制之间的相互作用会形成预起始复合体--一个包含RNA Pol II和一般转录因子IIA、Lib、LID、LiE、IIF和IIH的组件，而调控元件是序列特异性DNA结合蛋白的目标，这些蛋白包含影响转录激活或抑制的结构域。基因特异性激活子/抑制子与调控序列元件相互作用的累积效应，以及核心启动子元件与基础机制之间的相互作用，决定了任何特定基因的转录强度。正确调控基因表达的重要性怎么强调都不为过。转录调控的错误可能会导致许多有害的后果，包括但不限于发育缺陷、细胞增殖失控、不适当的细胞凋亡和代谢性疾病。转录调控的一个重要组成部分是通用转录因子LID(TFIID)。它是一个由TATA结合蛋白(TBP)和13-15个附加亚基组成的多亚基复合体，不仅是PIC的核组装，而且是许多转录调控因子的靶标和转导因子。我们希望了解TFIID复合体的多种成分如何共同作用，促进对人类健康至关重要的精确调控的基因表达。为此，我们将对TFIID或其组成亚基进行生化分析和高分辨率结构研究。我们将研究TFIID与激活剂或染色质之间的相互作用，并表征TFIID复合体中存在的内在酶活性。利用几种互补的生物物理技术，我们的目标是详细了解RNA Pol II转录复合体中这一中心成分的结构/功能关系。

DESCRIPTION (provided by applicant): In eukaryotic organisms, transcription of the messages contained within the genome is a tightly regulated process. Transcription occurs via the coordinated action of some 40-50 distinct protein components assembled into multiple complexes that cooperate to recognize transcription start sites, perform integration of regulatory signals, and provide the enzymatic activities necessary for the synthesis of RNA transcripts. Present within each gene are control elements that dictate how and when it is transcribed. For protein-coding genes transcribed by RNA polymerase II, interactions between the core promoter and the basal machinery nucleate formation of the pre-initiation complex - an assembly containing RNA Pol II and the general transcription factors, IIA, lIB, lID, lIE, IIF and IIH, while the regulatory elements are the targets of sequence-specific DNA-binding proteins that contain domains that affect activation or repression of transcription. The cumulative effects of gene specific activators/repressors interacting with regulatory sequence elements, as well as interactions between the core promoter elements and basal machinery, dictate the strength of transcription from any particular gene. The importance of the correct regulation of gene expression cannot be overstated. Errors in transcriptional control may lead to numerous deleterious outcomes that include but are not limited to, developmental defects, uncontrolled cell proliferation, inappropriate apoptosis, and metabolic diseases. An essential component for the proper regulation of transcription is general transcription factor lID (TFIID). It is a multi-subunit complex comprised of the TATA binding protein (TBP) and 13-15 additional subunits that not only nucleates assembly of the PIC, but is also the target and transducer of numerous transcriptional regulators. We wish to understand how the multiple components of the TFIID complex work together to facilitate precisely regulated gene expression which is essential for human health. To this end we will biochemically analyze and pursue high-resolution structural studies of TFIID or its constituent subunits. We will examine interactions between TFIID and activators or chromatin and characterize intrinsic enzymatic activities present within the TFIID complex. Using several complementary biophysical techniques, we aim to gain a detailed understanding of the structure/function relationships for this central component in the RNA Pol II transcription complex.