RNA Binding Proteins in Cancer

该项目的主要目标是了解RNA结合的机制， RBM 3蛋白在mRNA转录后水平调节基因表达 在癌细胞中的稳定性和翻译。我们已经确定， 蛋白质使正常细胞经历转化的表型，导致细胞 在免疫受损的小鼠中形成肿瘤。另一方面，RBM 3的敲除 由于有丝分裂灾难，表达导致细胞死亡。RBM 3与HuR相互作用， hnRNPA 1，并与AU-RNA序列，以提高mRNA的稳定性和翻译， 富含AU的转录物，如考克斯-2、VEGF和IL-8。此外，RBM 3过表达 增加Notch中雷帕霉素蛋白的哺乳动物靶标的活化 依赖机制我们还鉴定了RBM 3调控的microRNA 过度表达，包括下调抑制其自身表达的基因。我们 研究还表明，RBM 3在翻译后水平受到调节， 磷酸化、泛素化和SUMO化。根据这些观察，我们 提出三个具体目标。在目标1中，我们将确定RNA 结合蛋白RBM 3调节基因表达。在这里，我们将识别RNA 与RBM 3相互作用的序列。此外，我们还将确定 考克斯-2 3 'UTR，其是RBM 3介导的考克斯-2 mRNA稳定性所需的， 翻译.我们还将确定HuR和hnRNP-A1在此过程中的作用。在目标2中， 我们将确定RBM 3中经历磷酸化、泛素化和 通过诱变进行SUMO化。我们还将确定突变体对 mRNA的稳定性和翻译。在目标3中，我们建议通过以下方式确定机制： 其中RBM 3诱导肿瘤发生。我们将使用异种移植癌症模型， 确定mTOR和Notch通路在RBM 3介导的肿瘤发生中的作用。还有， 将确定microRNA在肿瘤发生中的作用。完成这些 实验应该能让我们更好地理解RNA结合蛋白 RBM 3在正常上皮细胞中起作用，以及RBM 3表达是否改变 在肿瘤细胞中观察到的是负责肿瘤行为的。

The broad goal of the project is to understand the mechanisms by which RNA binding protein RBM3 regulates gene expression at the posttranscriptional level of mRNA stability and translation in cancer cells. We have identified that overexpression of the protein causes a normal cell to undergo a transformed phenotype resulting in the cells forming tumors in immunocompromized mice. On the other hand, knockdown of RBM3 expression results in cell death due to mitotic catastrophe. RBM3 interacts with HuR and hnRNP A1, and with AU-RNA sequences to enhance mRNA stability and translation of AU-rich transcripts such as COX-2, VEGF and IL-8. In addition, RBM3 overexpression increases the activation of the mammalian target of rapamycin protein in a Notch dependent mechanism. We have also identified microRNAs regulated upon RBM3 overexpression, including downregulating one that inhibits its own expression. Our studies also suggest that RBM3 is regulated at the posttranslational levels of phosphorylation, ubiquitination and SUMOylation. Based on these observations, we propose three specific aims. In Aim 1, we will determine the mechanism by which RNA binding protein RBM3 regulates gene expression. Here, we will identify the RNA sequences that interact with RBM3. In addition, we will determine the sequenced in COX-2 3'UTR that are required for RBM3-mediated COX-2 mRNA stability and translation. We will also identify the role of HuR and hnRNP-A1 in the process. In Aim 2, we will determine the residues in RBM3 that undergo phosphorylation, ubiquitination and SUMOylation by mutagenesis. We will also determine the effect of the mutants on mRNA stability and translation. In Aim 3, we propose to determine the mechanisms by which RBM3 induces tumorigenesis. We will use an xenograft cancer model to determine the role of mTOR and Notch pathway in RBM3 mediated tumorigenesis. Also, the role of microRNAs in the tumorigenesis will be determined. Completion of these experiments should give us a better understanding of how the RNA binding protein RBM3 functions in normal epithelial cells, and whether changes in the RBM3 expression that is observed in tumor cells is responsible for tumor behavior.