2009年5月12日，北京生命科學(xué)研究所高紹榮實(shí)驗(yàn)室在Cell Research雜志在線發(fā)表題為“Pins homolog LGN regulates meiotic spindle organization in mouse oocytes”的文章,，該文章報(bào)道了LGN在小鼠卵母細(xì)胞成熟過程中的定位和功能,。
小鼠卵母細(xì)胞的減數(shù)分裂是極端的細(xì)胞不對稱分裂，排出的極體很小,、沒有明顯的生物學(xué)功能,，而卵母細(xì)胞卻要留下大部分的母源物質(zhì)以支持早期的胚胎發(fā)育。這種不對稱分裂的實(shí)現(xiàn)需要桶狀紡錘體向卵母細(xì)胞皮質(zhì)區(qū)域的遷移以及皮質(zhì)區(qū)域的極化,。本論文研究進(jìn)化上保守的Pins同源物在小鼠卵母細(xì)胞中的功能,。LGN是在小鼠卵母細(xì)胞中表達(dá)的Pins同源物。在生發(fā)泡期的卵母細(xì)胞中,，LGN定位在卵母細(xì)胞質(zhì)中和細(xì)胞皮質(zhì)上,。隨著卵母細(xì)胞的成熟，細(xì)胞質(zhì)中的LGN定位在減數(shù)分裂紡錘體上,，而皮質(zhì)上原本均勻分布的LGN則被極化,，在將來排出極體的地方特異性地消失。LGN在小鼠卵母細(xì)胞內(nèi)的過量表達(dá)會導(dǎo)致紡錘體伸長,、紡錘體兩極過度收攏以及紡錘體兩極?-tubulin的脫離,，而LGN的下調(diào)則會導(dǎo)致染色體聚集排列以及紡錘體裝配的缺陷。進(jìn)一步的結(jié)構(gòu)域分析發(fā)現(xiàn)LGN的N-端區(qū)域主要負(fù)責(zé)對紡錘體形態(tài)結(jié)構(gòu)的調(diào)節(jié),，而LGN C-端區(qū)域負(fù)責(zé)LGN在皮質(zhì)上的定位和極化,。這些發(fā)現(xiàn)表明LGN在卵母細(xì)胞成熟過程中參與皮質(zhì)區(qū)域的極化并且在紡錘體裝配過程中起重要作用。
該文章的第一作者為郭欣政,，通訊作者為高紹榮博士,，該項(xiàng)研究由科技部863項(xiàng)目資助。（生物谷Bioon.com）
生物谷推薦原始出處：
Cell Research advance online publication 12 May 2009; doi: 10.1038/cr.2009.54
Pins homolog LGN regulates meiotic spindle organization in mouse oocytes
Xinzheng Guo1,2 and Shaorong Gao2
1College of Life Science, Peking University, Beijing 100871, China
2National Institute of Biological Sciences, Beijing 102206, China
Mouse oocytes undergo polarization during meiotic maturation, and this polarization is essential for asymmetric cell divisions that maximize retention of maternal components required for early development. Without conventional centrosomes, the meiotic spindle has less focused poles and is barrel-shaped. The migration of meiotic spindles to the cortex is accompanied by a local reorganization and polarization of the cortex. LGN is a conserved protein involved in cell polarity and regulation of spindle organization. In the present study, we characterized the localization dynamics of LGN during mouse oocyte maturation and analyzed the effects of LGN upregulation and downregulation on meiotic spindle organization. At the germinal vesicle stage, LGN is distributed both cytoplasmically and at the cortex. During maturation, LGN localizes to the meiotic spindle apparatus and cortical LGN becomes less concentrated at the actin cap region. Excessive LGN induces meiotic spindle organization defects by elongating the spindle and enhancing pole focusing, whereas depletion of LGN by RNA interference results in meiotic spindle deformation and chromosome misalignment. Furthermore, the N-terminus of LGN has the ability of full-length LGN to regulate spindle organization, whereas the C-terminus of LGN controls cortical localization and polarization. Our results reveal that LGN is cortically polarized in mouse oocytes and is critical for meiotic spindle organization.
