Functional Analysis of CDKp110 Protein Kinase

描述（由申请人提供）：细胞分裂激酶（CDKs）具有多种功能，其中大多数与细胞分裂和/或转录的控制显著相关。我们的实验室发现了一个新的CDK亚家族，CDK11蛋白激酶，以前被称为PITSLRE激酶。细胞周期蛋白L1和最近发现的细胞周期蛋白L2是cdk11亚型的调控伙伴。我们确定CDK11p110亚型是RNA聚合酶II （RNAP II）复合物的一个组成部分，这与它通过与一种新的RNA结合基序蛋白RBM16相互作用影响转录延伸和潜在转录起始的能力相一致。CDK11p110也存在于剪接体复合体中，并在mrna前剪接事件中发挥作用。这种功能在CDKs中是独一无二的，富含rs的一般前mrna剪接因子RNPS1和9G8被确定为真正的相互作用因子。CDK11p110/p58缺失小鼠胚胎不能发育到E3.5以上，这表明CDK11p110和/或CDK11p58激酶功能对囊胚后胚胎发育至关重要。综上所述，这些研究强烈表明，CDK11p110激酶的功能对于细胞周期中转录和RNA加工的正常调节至关重要。然而，我们不知道CDK11p110激酶功能如何协调调节RNAP II/剪接体复合物的组成/功能。基于我们的cdc2l基因敲除研究，CDK11p110/p58对正常胚胎发育至关重要，与其他CDKs不同（即，除了CDKs-1和-3），我们假设这些敲除小鼠的部分表型是由于缺乏CDK11p110而蛋白质的功能是发育所必需的。为了验证这些假设，我们提出了实验来回答以下具体目标：(1)CDK11p110激酶与RNAPII和剪接体复合体中因子的关联和/或磷酸化的功能意义是什么？CDK11p110在协调剪接和转录中起关键作用吗？(2) CK11p110亚型在胚胎发育中的作用是什么？如果只切除CDK11p110或CDK11，是否有可能获得可存活的胚胎？如果是这样，这些小鼠是否更容易患肿瘤或发育缺陷？

DESCRIPTION (provided by applicant): The cell division kinases (CDKs) have diverse functions, most of which are prominently linked to the control of cells division and/or transcription. Our laboratory identified a novel CDK subfamily, the CDK11 protein kinases previously known as the PITSLRE kinases. Cyclin L1 and, more recently, cyclin L2, are regulatory partners of the CDK 11 isoforms. We determined that the CDK11p110 isoform is a component of RNA polymerase II (RNAP II) complexes, consistent with its demonstrated ability to influence transcriptional elongation and potentially transcriptional initiation via interaction with a novel RNA-binding motif protein RBM16. CDK11p110 is also found in spliceosome complexes and has a role in pre-mRNA splicing events. This function is unique among the CDKs, with the RS-rich general pre-mRNA splicing factors RNPS1 and 9G8 identified as bona fide interactors. CDK11p110/p58-null mouse embryos fail to develop past E3.5, indicating that CDK11p110 and/or CDK11p58 kinase function is essential for post-blastocyst embryonic development. Taken together, these studies strongly suggest that CDK11p110 kinase function is essential for normal regulation of transcription and RNA processing during the cell cycle. However, we do not know how CDK11p110 kinase function might coordinately regulate the composition/function of RNAP II/spliceosome complexes. Based upon our cdc2l gene knockout studies CDK11p110/p58 is essential for normal embryonic development, unlike other CDKs (i.e., with the exception of CDKs-1 and -3), we hypothesize that a portion of the phenotype of these knockout mice is due to the absence of CDK11p110 and that the functions of the protein are required for development. To test these hypotheses we propose experiments to answer the following specific aims: (1) What is the functional significance of CDK11p110 kinase association with and/or phosphorylation of factors in RNAPII and spliceosome complexes? Does CDK11p110 play a crucial role in coordinating splicing and transcription? (2) What is the function of the CK11p110 isoform in the developing embryo? Is it possible to obtain viable embryos if only CDK11p110 or CDK11 is ablated? If so, are these mice more prone to tumors or developmental defects?