Regulation and function of PIASy mediated mitotic SUMOylation in vertebrates

项目总结/摘要 在细胞分裂过程中，全套染色体需要在后期准确分离，以维持 完整的基因组信息后期染色体分离失败 导致子细胞中有偏见的基因组信息，这会导致发育缺陷， 肿瘤进展。有丝分裂染色体的精确结构组织是维持有丝分裂的关键因素。 染色体分离的完整性，这是由多个翻译后蛋白质修饰调节 系统.遗传学和生物化学研究都表明， 通过小泛素样调节剂（SUMO）修饰途径的修饰具有重要作用， 有丝分裂的正常进程。我已经发现有丝分裂特异性SUMO-2修饰在有丝分裂中起着至关重要的作用。 在非洲爪蟾卵提取物分析系统中完成了染色体的后期分离。这 有丝分裂SUMO-2修饰特别需要PIASy蛋白的活性，PIASy蛋白是SUMO-2修饰的成员。 E3的保守皮亚斯家族。PIASy介导多有丝分裂染色体上的SUMO-2修饰 proteins.有丝分裂中SUMO化的抑制导致后期染色体分离受损。 在有丝分裂过程中，PIASy介导的SUMO-2主要底物是DNA拓扑异构酶II（TopoII）， 已知在组织有丝分裂染色体中具有重要功能。抑制SUMO化改变 TopoII的染色体联合状态。 我推测PIASy介导的有丝分裂SUMO化在 通过其底物调节有丝分裂染色体的组织，这在 后期染色体分离。我建议研究PIASy特异性的调节机制， SUMO化途径（Aim 1）和有丝分裂SUMO化的结果， TopoII SUMO化（Aim 2）和通过使用PARP 1（Aim 3）确定新型PIASy底物的功能 以非洲爪蟾卵提取物为模型体系。这项研究将证明SUMO-2的功能 脊椎动物有丝分裂染色体组织的改变。确定监管机制 PIASy介导的SUMO化将为理解SUMO化提供宝贵的信息 这是一种对多种细胞生理功能有影响的途径。项目叙述 与有丝分裂中基因组DNA的分离特别相关的问题对于理解 脊椎动物细胞的基础生物学和解决人类癌症的分子基础， 基因组DNA分离的错误调节导致基因组不稳定。我提出的研究将提供 深入了解有丝分裂期间SUMO蛋白质修饰的后果和有丝分裂的调节 有望为化疗药物的改良提供新的信息。

Project Summary/Abstract During cell division, the full set of chromosomes needs to separate accurately at anaphase to maintain complete genomic information in each daughter cell. Failure of proper chromosome segregation at anaphase leads to biased genomic information in daughter cells, which causes developmental defect and contributes to tumor progression. Precise structural organization of mitotic chromosomes is a key element in maintaining integrity of chromosome segregation, which is regulated by multiple posttranslational protein modification systems. Both genetic and biochemical studies indicate that the posttranslational protein modification by Small Ubiquitin-like MOdifier (SUMO) modification pathway has an important role in normal progression of mitosis. I have found that mitotic specific SUMO-2 modification has a crucial role for completion of faithful chromosome segregation in anaphase in Xenopus egg extract assay system. This mitotic SUMO-2 modification specifically requires the activity of the PIASy protein that is a member of conserved PIAS family of E3. PIASy mediates SUMO-2 modification on multiple mitotic chromosomal proteins. Inhibition of SUMOylation in mitosis causes compromised chromosome segregation at anaphase. The major PIASy-mediated SUMO-2 substrate during mitosis is DNA topoisomerase II (TopoII), which is known to have an essential function in organizing mitotic chromosomes. Inhibition of SUMOylation alters chromosomal association status of TopoII. I hypothesize that the PIASy-mediated mitotic SUMOylation has an essential function in regulating the organization of mitotic chromosomes via its substrates, which plays a crucial role in chromosome segregation at anaphase. I propose to investigate a regulatory mechanism of PIASy specific SUMOylation pathway (Aim1) and a consequence of mitotic SUMOylation with determining the function of TopoII SUMOylation (Aim2) and determining the function of novel PIASy substrates, PARP1 (Aim3) by using Xenopus egg extracts as a model system. This investigation will demonstrate the function of SUMO-2 modification in organization of mitotic chromosomes in vertebrates. Determination of regulatory mechanisms of PIASy mediated SUMOylation will provide an invaluable information for understanding SUMOylation pathway that has an impact on diverse cellular physiological functions. Project Narrative Questions specifically related to separation of genomic DNA in mitosis are important both in understanding the fundamental biology of vertebrate cells and in addressing the molecular basis of human cancers caused by mis-regulation of genomic DNA separation resulting in genomic instability. My proposed research will provide insight into the consequences of protein modification by SUMO during mitosis and regulation of mitotic chromosomes and expected to provide the novel information for improvement of chemotherapeutic agents.