Causes and Consequences of Aneuploidy in HeSCs

项目总结/摘要 在细胞分裂过程中，染色体必须准确地分离，以产生具有正确染色体的子细胞。 染色体数目，而分离错误产生非整倍体细胞， 染色体在正常的人体细胞中，染色体分离错误和非整倍体是罕见的。在 相反，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， 非整倍体是导致流产和出生缺陷的主要原因。然而，我们不明白， 机制负责这一点，特别是有丝分裂错误。此外，考虑到如此高的有丝分裂错误率， 有人提出，随着发育的进行，二倍体细胞可以胜过非整倍体细胞， 胚胎，但这是如何发生的是未知的。我们将利用多能基因来填补我们知识中的这些空白， 人类胚胎干细胞（hESC）和定量成像，化学和基因组学的组合 接近。该基金的具体目标是：（1）确定负责以下过程的有丝分裂途径： hESC中的染色体分离错误，（2）确定hESC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如何随后损害hESC 对胚胎组织的贡献。总的来说，这些目标测试了我们的总体假设，即多能性 胚胎细胞与体细胞在支持 染色体分离保真度和对非整倍体的反应。此外，这项工作奠定了 我们的长期目标是确定负责的分子信号通路的基础， 胚胎细胞中非整倍性的原因、耐受性和后果，以及开发 保持培养中生长的胚胎细胞的基因组完整性，以提高生殖和 再生医学疗法总之，这项工作将揭示这两个机制的基础上， 胚胎细胞中的非整倍性以及如何最终实现核型稳定性以支持正常人类 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.