Cyclin B functions as a regulatory protein through association with its catalytic partner Cdc2 kinase forming M−phase promoting factor (MPF), which plays a central role in the meiotic maturation of oocyte. To gain insight into the molecular events, we here cloned a cyclin B cDNA from the ovary of the prawn Macrobrachium rosenbergii and compared its spatial–temporal expression patterns during oocyte maturation with those of crab Eriocheir sinensis. The prawn cyclin B cDNA encodes a 398 amino acid protein with predicted molecular weight of 45.16 kDa. Immunodetection of cyclin B protein by Western blot showed that a target band of approximately 53 kDa protein in the prawn ovaries at both late vitellogenesis (lVt) and germinal vesicle breakdown (GVBD) stages, whereas a 41 kDa band was present in the crab ovaries. Cyclin B protein expression changes indicating that the newly synthesis of cyclin B proteins could be required for GVBD in both prawn and crab. Immunohistochemical analysis revealed that both the prawn and crab cyclin B proteins, were localized in the ooplasm of previtellogenic oocytes, then relocated into germinal vesicle at vitellogenesis stage and localized on meiotic spindle at M phase. These similar behaviors suggested that the prawn and the crab cyclin B proteins associated with Cdc2 kinase have conserved roles in inducing GVBD and regulating the formation of meiotic spindle. The similar expression patterns of the cyclin B proteins during oocyte maturation implicated that the molecular mechanisms for MPF activation could be identical between the prawn and the crab.

细胞周期蛋白B通过与其催化伴侣Cdc2激酶形成M期促进因子（MPF）的结合而起调节蛋白的作用，在卵母细胞的减数分裂成熟中起着核心作用。为了深入了解分子事件，我们在这里从对虾罗氏沼虾的卵巢中克隆了cyclin B cDNA ，并将其在卵母细胞成熟过程中的时空表达模式与中华绒螯蟹的时空表达模式进行了比较。。虾细胞周期蛋白B cDNA编码398个氨基酸，预测分子量为45.16 kDa。通过蛋白质印迹法对细胞周期蛋白B蛋白进行免疫检测显示，在卵黄体形成后期（lVt）和生胚囊泡破坏（GVBD）阶段，虾卵巢中的目标条带约为53 kDa，而蟹的卵巢中存在41 kDa的条带。细胞周期蛋白B蛋白表达变化表明，虾和蟹的GVBD可能需要新合成细胞周期蛋白B蛋白。免疫组织化学分析显示，虾和蟹cyclin B蛋白均定位在前玻璃体形成卵母细胞的卵泡中，然后在卵黄发生期重新定位到生发囊泡中，并在M期定位在减数分裂纺锤体上。这些相似的行为表明，与Cdc2激酶相关的虾和蟹cyclin B蛋白在诱导GVBD和调节减数分裂纺锤体的形成中具有保守作用。卵母细胞成熟过程中细胞周期蛋白B蛋白的相似表达模式表明，虾和蟹之间MPF激活的分子机制可能相同。