报告题目：Causes of aneuploidy in eggs（卵细胞染色体非整倍性的原因）
Errors in chromosome segregation during meiosis I in oocytes are a leading cause of pregnancy loss and severe birth defects such as Down syndrome. The frequency of errors in chromosome segregation is higher in oocytes compared to other type of cell division, and further increases with maternal age. Why chromosome segregation during meiosis I in oocytes is so error prone and how it is related to age remain poorly understood.
We study the causes of chromosome segregation errors using mouse oocytes as a model. In this seminar, our results on cell biological mechanisms and age-related defects that contribute to the errors will be presented. First, we demonstrate that the large cytoplasm of oocytes, which is presumably crucial for post-fertilization development, is linked to the error-prone nature of oocytes. Second, we show that premature separation of homologous chromosomes is the major cause of chromosome segregation errors in naturally aged oocytes. These results serve as a framework for studying molecular mechanisms of the causes of chromosome segregation errors during meiosis I in mammalian oocytes.
1. Kyogoku & Kitajima, Developmental Cell 41(3), 287-298 (2017)
2. Sakakibara et al., Nature Communications 6:7550 (2015)