College of Life Sciences, Shandong Normal University, Jinan, Shandong, China.
Cell Cycle. 2010 Jun 1;9(11):2230-6. doi: 10.4161/cc.9.11.11895.
Spindly was first identified in Drosophila; its homologues are termed SPDL-1 in Caenorhabditis elegans and Hs Spindly/hSpindly in humans. In all species, Spindly and its homologues function by recruiting dynein to kinetochores and silencing SAC in mitosis of somatic cells. Depletion of Spindly causes an extensive metaphase arrest during somatic mitoses in Drosophila, C. elegans and humans. In Drosophila, Spindly is required for shedding of Rod and Mad2 from the kinetochores in metaphase; in C. elegans, SPDL-1 presides over the recruitment of dynein and MDF-1 to the kinetochores; in humans, Hs Spindly is required for recruiting both dynein and dynactin to kinetochores but it is dispensable for removal of checkpoint proteins from kinetochores. The present study was designed to investigate the localization and function of the Spindly homologue (mSpindly) during mouse oocyte meiotic maturation by immunofluorescent analysis, and by overexpression and knockdown of mSpindly. We found that mSpindly was typically localized to kinetochores when chromatin condensed into chromosomes after GVBD. In metaphase of both first meiosis and second meiosis, mSpindly was localized not only to kinetochores but also to the spindle poles. Overexpression of mSpindly did not affect meiotic progression, but its depletion resulted in an arrest of the pro-MI/MI stage, failure of anaphase entry and subsequent polar body emission, and in abnormal spindle morphology and misaligned chromosomes. Our data suggest that mSpindly participates in SAC silencing and in spindle formation as a recruiter and/or a transporter of kinetochore proteins in mouse oocytes, but that it needs to cooperate with other factors to fulfill its function.
Spindly 最初在果蝇中被鉴定出来；其同源物在秀丽隐杆线虫中称为 SPDL-1，在人类中称为 Hs Spindly/hSpindly。在所有物种中，Spindly 及其同源物通过将动力蛋白招募到动粒并在体细胞有丝分裂中沉默 SAC 来发挥作用。Spindly 的耗竭会导致果蝇、秀丽隐杆线虫和人类体细胞有丝分裂中期出现广泛的中期停滞。在果蝇中，Spindly 是 Rod 和 Mad2 从中期动粒上脱落所必需的；在秀丽隐杆线虫中，SPDL-1 主持动力蛋白和 MDF-1 向动粒的募集；在人类中，Hs Spindly 招募动力蛋白和 dynactin 到动粒是必需的，但它对于从动粒上去除检查点蛋白是可有可无的。本研究旨在通过免疫荧光分析以及 mSpindly 的过表达和敲低来研究 Spindly 同源物（mSpindly）在小鼠卵母细胞减数分裂成熟过程中的定位和功能。我们发现，在 GVBD 后染色质浓缩成染色体时，mSpindly 通常定位于动粒上。在第一次减数分裂和第二次减数分裂的中期，mSpindly 不仅定位于动粒上，还定位于纺锤体极上。mSpindly 的过表达不会影响减数分裂进程，但它的耗竭会导致前 MI/MI 期停滞、后期进入失败和随后的极体发射，以及异常的纺锤体形态和染色体排列不齐。我们的数据表明，mSpindly 作为动粒蛋白的招募者和/或转运体，参与 SAC 沉默和纺锤体形成，但它需要与其他因素合作来发挥其功能。
