CAREER: Core Promoter-Selective Transcription by RNA Polymerase II

真核生物蛋白质编码基因的差异转录调控是在多个水平上控制的，涉及调控DNA序列和核心启动子DNA元件的组合功能。核心启动子是包含基因转录起始位点的最小DNA区域，其被普遍存在的基础/一般转录机制识别，并且足以在体外指导RNA聚合酶II的特异性转录起始。相比之下，调控DNA序列位于距核心启动子不同距离处，并被多种序列特异性DNA结合转录调控因子识别，这些序列特异性DNA结合转录调控因子可以是组织特异性的或发育调控的，并影响核心启动子处基础转录机制的募集或活性。因此，核心启动子和相关的基础转录机制是转录调控信号的最终目标。重要的是，核心启动子的结构不仅影响启动子的基础活性，而且影响其对特定增强子和转录调节子的选择性应答。然而，核心启动子如何促进基因选择性转录调控尚不清楚。已经鉴定了各种核心启动子DNA元件，包括TATA盒、起始子、DPE等。除了TATA盒之外，其他元件的功能仍然没有得到很好的描述。令人惊讶的是，最近对果蝇和人类的分析表明，大多数蛋白质编码基因缺乏TATA盒。虽然已经了解了很多关于转录起始和调节的TATA盒基因的机制，基本的机器和转录起始的机制，在更大的类TATA-少的基因仍然知之甚少。Martinez博士以前的工作表明，存在核心启动子特异性的基础因子和替代途径，用于在TATA较少的核心启动子处特异性转录起始。该CAREER项目的具体研究目标是（i）纯化和鉴定核心启动子特异性基础因子，这些基础因子对启动子功能和TATA-less启动子依赖性转录至关重要，以及（ii）表征这些核心启动子特异性基础因子在体外和人类细胞中的分子功能。通过该项目的教育部分（分子生物学、转录和染色质的本科生和研究生课程，以及重点研究基因调控、染色质和细胞信号传导的新本科生实验室课程的开发），将加强生物化学和分子生物学的本科生、研究生和博士后教育和培训。 将强调少数民族学生在加州大学河滨分校的参与。 马丁内斯博士实验室的少数民族本科生一直在参加各种"少数民族准入计划"，包括加州少数民族参与科学联盟（CAMP）计划。

Differential transcription regulation of eukaryotic protein-coding genes is controlled at multiple levels and involves the combinatorial function of regulatory DNA sequences and core promoter DNA elements. The core promoter is the minimal DNA region encompassing the transcription start site of a gene that is recognized by the ubiquitous basal/general transcription machinery and is sufficient to direct specific transcription initiation by RNA polymerase II in vitro. In contrast, regulatory DNA sequences are located at varying distances from the core promoter and are recognized by a variety of sequence-specific DNA-binding transcription regulators, which can be tissue-specific or developmentally regulated and influence the recruitment or activity of the basal transcription machinery at the core promoter. Thus, the core promoter and the associated basal transcription machinery are the ultimate targets of transcription regulatory signals. Significantly, the structure of the core promoter influences not only the basal activity of a promoter but also its selective response to specific enhancers and transcription regulators. How core promoters contribute to gene-selective transcription regulation is however unclear. Various core promoter DNA elements including the TATA box, the initiator, the DPE, and others have been identified. With the exception of the TATA box, the functions of the other elements are still poorly characterized. Surprisingly, recent analyses in Drosophila and humans have revealed that most protein-coding genes lack a TATA box. Although much has been learned about the mechanisms of transcription initiation and regulation of TATA box-containing genes, the basal machinery and the mechanisms of transcription initiation at the larger class of TATA-less genes remain poorly understood. Previous work by Dr. Martinez has indicated the existence of core promoter-specific basal factors and alternative pathways for specific transcription initiation at TATA-less core promoters. The specific research goals of this CAREER project are (i) to purify and identify the core promoter-specific basal factors that are essential for initiator function and initiator-dependent transcription from TATA-less promoters and (ii) to characterize the molecular functions of these core promoter-specific basal factors in vitro and in human cells. Through the educational component of this project (undergraduate and graduate courses in molecular biology, transcription and chromatin, and the development of a new undergraduate laboratory course focused on research in gene regulation, chromatin, and cell signaling), undergraduate, graduate and postdoctoral education and training in biochemistry and molecular biology will be enhanced. Participation of minority students at the University of California-Riverside will be emphasized. Undergraduate minority students in Dr. Martinez's laboratory have been participating in various "minority access programs" including the California Alliance for Minority Participation in Science (CAMP) program.