Mechanisms of chromosome segregation, aneuploidy, and tumorigenesis

项目总结 染色体错误分离或胞质分裂中的错误会产生非整倍体，即染色体内容不同于 单倍体数量的倍数。人们很早就认识到非整倍体与肿瘤发生的联系。惊人的一击 与染色体错误分离相关的染色体异常是染色质病(也称为 染色体再发生)，一条(或两条)染色体看起来已经分裂成十条到 数百个小的基因组片段，并以随机的顺序重新组合在一起。致变色染色体 现已被认为存在于多种癌症中。 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的行为，并确定了单个染色体 分离错误或短暂的纺锤体极放大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复制起到纠错作用 保持这种身份的机制。我们已经确定了支持有丝分裂的关键分子机制 检查点(也称为纺锤体组件检查点)，主要防御染色体 哺乳动物中的错误分离。我们已经确定了有丝分裂检查点激活和沉默是如何涉及 构象改变AAA+ATPase TRIP13的催化作用。我们还确定了有丝分裂的退出 对TRIP13介导的检查点抑制物或非必需的拆解的绝对要求 APC15是E3泛素连接酶的亚基，以有丝分裂周期蛋白破坏为靶标。通过利用的一项独特功能 人的Y着丝粒，我们已经制造了细胞，在其中我们可以诱导选择性的、瞬时的失活 Y着丝粒，Y染色体高频率误分离成微核。有了这些和完整的 基因组测序，我们确定了简单的微核错误分离可以引发染色体萎缩症 并推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碎裂的机制 嗜铬细胞病，鉴定和验证粉碎微核染色体的核酸酶，确定如何 破碎的染色体被重组并产生染色体外DNA(EcDNA)，确定 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 在过去15年中，神经系统疾病的反义寡核苷酸(ASO)疗法的发展 通过测试进行针对有丝分裂检查点失活的原则证明治疗开发 TRIP13/APC15抑制主要脑癌胶质母细胞瘤的疗效

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.