Mechanisms of chromosome segregation, aneuploidy, and tumorigenesis

项目摘要 染色体错误分离或胞质分裂中的错误产生非整倍体， 的倍数。非整倍体与肿瘤发生的关系早已被认识。一个引人注目 与染色体错误分离有关的染色体异常是染色体裂（也称为染色体裂）。 染色体再生（chromoanagenesis），一个（或两个）染色体似乎已经破碎成数十个， 数百个小的基因组片段，并以随机顺序重新连接在一起。染色体断裂 现在被认为存在于广泛的癌症中。 在NIGMS R35基金的支持下，我们已经确定了正常染色体分离的机制， 在正常情况下防止非整倍体，并确定单个染色体 错误分离或瞬时纺锤极扩增是肿瘤发生的驱动因素。我们已经确定了 着丝粒身份的表观遗传标记，并确定DNA复制作为错误校正 保持这种身份的机制。我们已经确定了有丝分裂的关键分子机制， 检查点（也称为纺锤体组装检查点），是防止染色体 哺乳动物的错误隔离我们已经确定了有丝分裂检查点的激活和沉默是如何参与细胞分裂的。 构象改变AAA+ ATP酶TRIP 13的催化作用。我们还确定，有丝分裂退出 TRIP 13介导的检查点抑制剂或非必需物质分解的绝对要求 靶向有丝分裂细胞周期蛋白破坏的E3泛素连接酶的APC 15亚基。通过利用一个独特的功能， 人类Y着丝粒，我们已经产生了细胞，我们可以诱导选择性，短暂失活的 Y着丝粒，Y染色体以高频率错分离为微核。有了这些和整个 通过基因组测序，我们确定了进入微核的简单错误分离可以启动染色体断裂 并驱动人类癌症中常见的复杂基因组重排。 在接下来的5年里，我们建议确定染色体断裂的机制， chromothripsis，识别和验证核酸酶片段微核染色体，确定如何 破碎的染色体重新组装并产生染色体外DNA（ecDNA）， ecDNA的遗传机制，并确定空间邻近在着丝粒遗传中的作用 身份，包括新着丝粒形成和其他基因组异常。我们还将利用我们的 过去15年来，反义寡核苷酸（阿索）治疗神经系统疾病的发展， 通过测试进行靶向有丝分裂检查点失活的原理性疗法开发的证明 抑制TRIP 13/APC 15用于主要的脑癌胶质母细胞瘤。

PROJECT SUMMARY Chromosome missegregation or errors in cytokinesis produce aneuploidy, a chromosome content other than a multiple of the haploid number. The linkage of aneuploidy to tumorigenesis has long been recognized. A striking chromosomal abnormality linked to chromosome missegregation is chromothripsis (also known as chromoanagenesis), an event in which one (or two) chromosomes appear to have been shattered into tens to hundreds of small genomic fragments and religated back together in random order. Chromotriptic chromosomes are now recognized to be present in a broad range of cancers. With support from an NIGMS R35 grant, we have identified mechanisms of normal chromosome segregation that act to prevent aneuploidy in the normal situation and have determined that single chromosome missegregation or transient spindle pole amplification is a driver of tumorigenesis. We have identified the epigenetic mark of centromere identity and determined that DNA replication acts as an error correction mechanism to maintain that identity. We have identified key molecular mechanisms underlying the mitotic checkpoint (also known as the spindle assembly checkpoint), the primary guard against chromosome missegregation in mammals. We have identified how both mitotic checkpoint activation and silencing involve the catalytic action of a conformation altering AAA+ ATPase TRIP13. We have also determined that mitotic exit has an absolute requirement for TRIP13-mediated disassembly of the checkpoint inhibitor or the non-essential APC15 subunit of the E3 ubiquitin ligase that targets mitotic cyclin destruction. By exploiting a unique feature of the human Y centromere, we have produced cells in which we can induce selective, transient inactivation of the Y centromere, with the Y chromosome missegregated into micronuclei at high frequency. With these and whole genome sequencing, we determined that simple missegregation into a micronucleus can initiate chromothripsis and drive the complex genome rearrangements frequently found in human cancer. In the upcoming 5 years, we propose to determine mechanisms of fragmentation of a chromosome during chromothripsis, identify and validate nucleases that fragment micronuclear chromosomes, determine how shattered chromosomes are reassembled and produce extrachromosomal DNA (ecDNA), determine mechanisms of inheritance of ecDNA, and determine the role of spatial proximity in the inheritance of centromere identity, including neocentromere formation and other genomic abnormalities. We will also exploit our development over the last 15 years of antisense oligonucleotide (ASO) therapy for nervous system disease to undertake proof of principle therapy development targeting inactivation of the mitotic checkpoint by testing suppression of TRIP13/APC15 for the major brain cancer glioblastoma.