鯉魚減數分裂基因c-Mos功能與活性調控之探討

Abstract

細胞進行有絲分裂時，細胞核當中的遺傳物質-染色體需進行一次複製、濃縮、經由紡錘體分離平均分配到兩個子細胞。進行減數分裂的生殖細胞染色體也需要經過以上等過程，但不同的是減數分裂中染色體只複製一次，而後卻有連續兩次的分離，形成單套染色體配子。顯然有絲分裂的機制在細胞行減數分裂時受到了修飾與特化。在大部分的脊椎動物裡，未成熟的卵需進行減數分裂，爾後在第二次減數分裂作停留等待受精，此一過程稱之為卵的成熟作用。

Ran系統在有絲分裂進程中參與染色體以及紡錘體狀態的調控。而Mos是減數分裂時的特有激酶，影響減數分裂時紡錘體形成、維持、變動以及染色體組態。為了探討此二者共同作用於M phase時，彼此之間交互作用狀況為何，因此選殖了鯉魚卵巢內的Mos基因異位表現於COS-1細胞，並觀察Mos與Ran是否有直接的結合。實驗結果發現，在此狀況下，針對Mos的共免疫沈澱複合物當中含有Hsp70/90等協助Mos構型的蛋白存在，而此共免疫複合沈澱物亦具有酶激活性，但卻無法偵測到Ran存在於其中。

Abstract In most vertebrate animals, the development of the immature oocyte into a fertilizable gamete, a process known as oocyte maturation, involves an arrest in the meiotic cell cycle while awaiting fertilization. Mos, a serine/threonine kinase, is specifically expressed during meiotic maturation of vertebrate oocytes. After germinal vesicle breakdown (GVBD), Mos is involved in the regulation of meiotic spindle assembly and chromatin organization. The activation of this kinase is also essential for the maintenance of metaphase Ⅱ arrest. Ran GTPase, which belongs to the Ras superfamily of small GTPase, and the protein that regulate its GTP binding and hydrolysis has a well-defined role in nuclear transport. Recent studies indicate that Ran has a central role in spindle assembly and nuclear envelope reformation. It seems that Ran system and Mos pathway coordinate in some events in M phase. To understand the inter-relationship of them, I ectopically express Carp Mos gene in COS-1 cell and investigate Mos-interacting proteins. Heat Shock Protein-Hsp70 and Hsp90 are detected in Mos co-immunoprecipitation complex with or without kinase activity, but Ran dose not exist in the complex.