Posttranscriptional control of gene expression

基因表达的转录后控制

• 批准号: 6763555
• 负责人: BARBARA K FELBER
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6763555
• 关键词: RNA binding protein; human immunodeficiency virus 1; intracellular transport; messenger RNA; microorganism culture; posttranscriptional RNA processing; type D retrovirus group; virus RNA; virus genetics

Our research focuses on regulation of gene expression, in particular the mechanisms controlling cellular and viral mRNA expression. The use of retroviral model systems, pioneered by research on HIV-1, have led to major discoveries in the field of mRNA metabolism. These studies have resulted in the elucidation of the major transport pathways from the nucleus utilized by both mRNAs and proteins. Our work led to the discovery of mechanisms governing posttranscriptional regulation of two key retroviral systems: human immunodeficiency virus type 1 (HIV-1) and simian type D retrovirus (SRV). Whereas the posttranscriptional expression of HIV-1 is mediated through the essential viral Rev protein interacting with the cis-acting Rev-responsive element (RRE), the expression of SRV is mediated through a cellular factor interacting with the cis-acting constitutive transport element (CTE). The mechanisms promoting expression of viral mRNAs also involve cellular factors; therefore, their identification and characterization is important for our understanding of cellular gene expression. My lab investigates the molecular steps mediating cellular mRNA transport and expression of HIV-1 and SRV using a combination of biochemistry and tools of functional genomics and proteomics. The dissection of the mechanisms of posttranscriptional control and nucleocytoplasmic trafficking of macromolecules are relevant to understand the processes involved in carcinogenesis. In previous studies, we have characterized the CTE RNA transportelements of the several simian type D retroviruses and some intracisternal A particle (IAP) retroelements. These studies identified that the overall structure and the sequence of the two internal loops are essential for function. By in vitro RNA selection, we have recently identified a genomic element with the properties of a primordial CTE, which is able to mediate RNA export from Xenopus oocyte nucleus (Zolotukhin, A. S., et al. J Virol. 75:5567-5575, 2001). These findings constitute direct evidence of an evolutionary link between these elements and CTE. We had identified NXF1 (formerly named TAP) as essential export receptor for the CTE RNA and as key transporter of cellular mRNA. NXF1 is the first identified export receptor for cellular mRNAs, thereby providing a direct link between mRNA and the nuclear pore complex. We further found that the NXF1 ortholog in C. elegans is an essential mRNA export factor, demonstrating conservation of NXF1 function in metazoa (Tan, W. et al. RNA. 6:1762-1772, 2000). Recent data from my lab revealed that NXF1 binds directly to the splicing factor U2AF (Zolotukhin et al, submitted). This interaction provides a novel link between splicing and export of mRNA. In collaboration with George Pavlakis, we identified a novel potent RNA transport element RTE (Nappi, F., et al.. J Virol. 75:45584569, 2001). We found that RTE function is conserved in vertebrates. The use of RTE provides us with a powerful tool for further dissection of mRNA transport mechanisms.

我们的研究重点是基因表达的调控，特别是控制细胞和病毒mRNA表达的机制。由HIV-1研究开创的逆转录病毒模型系统的使用导致了mRNA代谢领域的重大发现。这些研究已导致阐明mRNA和蛋白质利用的来自细胞核的主要转运途径。我们的工作导致了两个关键的逆转录病毒系统的转录后调控机制的发现：人类免疫缺陷病毒1型（HIV-1）和猿猴D型逆转录病毒（SRV）。HIV-1的转录后表达是通过与顺式作用Rev反应元件（RRE）相互作用的基本病毒Rev蛋白介导的，而SRV的表达是通过与顺式作用组成型转运元件（CTE）相互作用的细胞因子介导的。促进病毒mRNA表达的机制也涉及细胞因子;因此，它们的鉴定和表征对于我们理解细胞基因表达是重要的。我的实验室研究的分子步骤介导的细胞mRNA运输和表达的HIV-1和SRV使用生物化学和功能基因组学和蛋白质组学的工具相结合。大分子的转录后调控和核质运输机制的解剖有助于理解肿瘤发生的过程。 在以前的研究中，我们已经确定了几种猿猴D型逆转录病毒的CTE RNA转运元件和一些脑池内A颗粒（IAP）逆转录元件的特征。这些研究表明，整体结构和两个内部循环的顺序对功能至关重要。通过体外RNA选择，我们最近鉴定了具有原始CTE性质的基因组元件，其能够介导RNA从爪蟾卵母细胞核输出（Zolotukhin，A.美国，等人J Virol. 75：5567-5575，2001）。这些发现构成了这些元素和CTE之间进化联系的直接证据。 我们已经确定NXF 1（以前称为TAP）作为CTE RNA的必需输出受体和细胞mRNA的关键转运蛋白。NXF 1是第一个鉴定的细胞mRNA的输出受体，从而提供了mRNA和核孔复合物之间的直接联系。我们进一步发现，C.线虫是一种必需的mRNA输出因子，证明了NXF 1功能在后生动物中的保守性（Tan，W.等RNA. 6：1762-1772，2000）。我的实验室最近的数据显示，NXF 1直接与剪接因子U2 AF结合（Zolotukhin等人，提交）。这种相互作用在mRNA的剪接和输出之间提供了一种新的联系。在与乔治帕夫拉基斯的合作中，我们鉴定了一种新的有效RNA转运元件RTE（Nappi，F.，等. J Virol。75：45584569，2001）。我们发现RTE功能在脊椎动物中是保守的。RTE的使用为我们进一步剖析mRNA转运机制提供了有力的工具。