Regulation of RNA metabolism and cell growth control by SR protein kinases

基因表达的转录后调控对于细胞生长调控和动物实验都是至关重要的 发展该项目攻击SRPK 1和2，这两种进化保守的激酶对应于 哺乳动物细胞中剪接因子和调节因子SR家族的主要激酶活性。SR蛋白 参与RNA代谢的许多方面，所有这些似乎都受到磷酸化的调节。 引人注目的是，我们最近发现，SRPK 1基因缺失的小鼠胚胎成纤维细胞转化为 软琼脂试验和裸鼠试验。此外，SRPKs定位于细胞质中，并且可以在细胞内表达。 在特定信号的作用下被诱导转移到珠心。因此，SRPK基本上 对于细胞生长控制很重要，并且激酶系统可以通过信号传导来调节。 基于我们在本项目前几个供资期建立的专业知识， 对基因表达转录后调控感兴趣，并广泛发表和未发表 根据研究结果，我们建议在下一阶段的研究中，根据三个具体目标继续这项计划。要求1 是开发条件性基因敲除小鼠模型，以确定SRPK 1和 2.小鼠发育过程中的特征性激酶敲除小鼠胚胎成纤维细胞，提供 SRPKs在哺乳动物细胞RNA代谢中调节SR蛋白功能的遗传学证据。目的 2是通过测试三个特定假设来解决SRPK 1的假定肿瘤抑制活性：（1） SRPK 1可能通过SR蛋白调节癌基因和抑癌基因的选择性剪接; 介导的磷酸化可能起作用，重组新输出的mRNA-蛋白质复合物，以调节 SRPK 1介导的磷酸化可能在维持细胞质中的翻译中起关键作用。 通过调节转录和剪接之间的偶联来调节基因组稳定性。目标3是了解如何 SRPKs可能受信号传导调控。已经鉴定了一组SRPK相互作用蛋白， 许多是各种信号转导途径的已知组分。我们设计特定的实验， 了解一些特定的信号如何通过SRPKs转导来调节基因表达， 转录水平。总之，该项目将剖析一个前所未有的细胞转化途径。

Post-transcriptional regulation of gene expression is critical for cell growth control and animal development. This project attacks SRPK1 and 2, two evolutionary conserved kinases that correspond to the major kinase activity for the SR family of splicing factors and regulators in mammalian cells. SR proteins are involved in many aspects of RNA metabolism, all of which appear to be regulated by phosphorylation. Strikingly, we recently found that mouse embyo fibroblasts genetically deleted of SRPK1 are transformed in the soft agar assay and in nude mice. Furthermore, SRPKs are localized in the cytoplasm and can be induced to translocate to the nucelus in response to specific signals. Thus, SRPKs are fundamentally important for cell growth control and the kinase system may be regulated by signaling. Building upon our expertise established in the previous funding periods of this project, long-term interest in post-transcriptional regulation of gene expression, and extensive published and unpublished findings, we propose to continue this project under three specific aims for the next phase of research. Aim 1 is to develop conditional knockout mice models to determine the functional requirement for both SRPK1 and 2 during mouse development and characterize the kinase knockout mouse embryo fibroblasts to provide genetic evidence that SRPKs regulate the function SR proteins in RNA metabolism in mammalian cells. Aim 2 is to address the putative tumor suppressor activity of SRPK1 by testing three specific hypotheses: (1) SRPK1 may regulate alternative splicing of oncogenes and tumor supressors via SR proteins; (2) SRPK1- mediated phosphorylation may act to reorganize newly exported mRNA-protein complex to regulate translation in the cytoplasm; and (3) SRPK1-mediated phosphorylation may play a critical role in maintaining genomic stability by modulating the coupling between transcription and splicing. Aim 3 is to understand how SRPKs might be regulated by signaling. A panel of SRPK-interacting proteins have been identified and many are known components of various signal transduction pathways. We design specific experiments to understand how some specific signals may be transduced via SRPKs to regulate gene expression at post- transcriptional levels. Together, the project will dissect an unprecedented cellular transformation pathway.