Causes and Consequences of Aneuploidy in HeSCs

项目摘要/摘要 在细胞分裂过程中，染色体必须被准确分离，以产生具有正确 染色体数目，而分离错误产生的非整倍体细胞具有异常数目的 染色体。在正常的人类体细胞中，染色体分离错误和非整倍体是罕见的。在……里面 相比之下，在人类全能和多能胚胎细胞中，减数分裂和有丝分裂错误是常见的，结果 非整倍体是流产和出生缺陷的主要原因。然而，我们并不理解 对此负责的机制，特别是有丝分裂错误。此外，鉴于有丝分裂错误率如此之高， 随着整倍体的建立，二倍体细胞可以比非整倍体细胞更具竞争力。 胚胎，但这是如何发生的还不清楚。我们将使用多功能来解决我们知识中的这些差距 人类胚胎干细胞(HESCs)及其定量成像、化学和基因组学的组合 接近了。这笔赠款的具体目的是：(1)确定负责 HESCs中的染色体分离错误，(2)确定hESCs的G1细胞周期结构是否允许 对非整倍体的初始耐受性，以及(3)确定非整倍体基因组随后如何损害hESCs 对胚胎组织的贡献。总而言之，这些目标检验了我们的总体假设，即多能性 胚胎细胞与体细胞在机制上存在本质上的不同 染色体分离的保真度和它们对非整倍体的反应。此外，这项工作奠定了 为我们的长期目标奠定了基础，即确定负责的分子信号通路 胚胎细胞非整倍体的原因、耐受性和后果以及开发 保持培养中胚胎细胞的基因组完整性，以提高生殖和生殖的成功率 再生医学疗法。总之，这项工作将揭示这两种潜在的机制 胚胎细胞的非整倍体以及如何最终实现核型稳定以支持正常人类 发展。

PROJECT SUMMARY/ABSTRACT During cell division chromosomes must be accurately segregated to produce daughter cells with the correct numbers of chromosomes whereas segregation errors generate aneuploid cells with abnormal numbers of chromosomes. In normal human somatic cells, chromosome segregation errors and aneuploidy are rare. In contrast, in human totipotent and pluripotent embryonic cells meiotic and mitotic errors are common, resulting in aneuploidy being the leading cause of miscarriages and birth defects. Yet, we do not understand the mechanisms responsible for this, particularly for mitotic errors. Moreover, given such a high mitotic error rate, it is proposed that diploid cells can outcompete aneuploid cells as development progresses to establish euploid embryos, but how this occurs is unknown. We will address these gaps in our knowledge using pluripotent human embryonic stem cells (hESCs) and a combination of quantitative imaging, chemical, and genomics approaches. The specific aims of this grant are (1) to determine the mitotic pathways responsible for chromosome segregation errors in hESCs, (2) to determine if the G1 cell cycle structure of hESCs permits an initial tolerance to aneuploidy, and (3) to determine how an aneuploid genome subsequently impairs hESCs contribution to embryonic tissues. Collectively, these aims test our overarching hypothesis that pluripotent embryonic cells are inherently different from somatic cells with respect to mechanisms that support chromosome segregation fidelity and in their response to aneuploidy. Furthermore, this work lays the foundation for our long-term objectives of identifying the molecular signaling pathways responsible for the causes, tolerance, and consequences of aneuploidy in embryonic cells and for developing strategies that preserve the genome integrity of embryonic cells grown in culture to improve the success of reproductive and regenerative medicine therapies. In conclusion, this work will reveal both the mechanisms underlying aneuploidy in embryonic cells and how karyotype stability is eventually achieved to support normal human development.