HeLa细胞中细胞周期蛋白B不降解也能完成有丝分裂中后期转变

HeLa cells can pass through metaphase and anaphase successfully without cyclin B degradation

目的：在用细胞周期蛋白（ｃｙｃｌｉｎ）Ｂ１作为ＨｅＬａ细胞周期Ｇ１期时相的阴性标志物时，发现呈阳性结果，为此，对细胞周期蛋白Ｂ在细胞的Ｍ期向Ｇ１期过渡中的作用做进一步探讨。方法：分别用诺考达唑（ｎｏｃｏｄａｚｏｌｅ）和离心淘洗的方法同步化ＨｅＬａ细胞，用Ｗｅｓｔｅｒｎ印迹方法检测细胞周期蛋白Ｂ的存在。结果：用诺考达唑阻断细胞于Ｍ期，然后释放４ｈ所得的Ｇ１期细胞中有细胞周期蛋白Ｂ，而离心淘洗的方法所得Ｇ１期细胞中没有细胞周期蛋白Ｂ。结论：（１）诺考达唑阻断细胞于Ｍ期后，可影响细胞周期蛋白Ｂ１在Ｍ期后期的降解；（２）细胞周期蛋白Ｂ１的降解对于ＨｅＬａ细胞由Ｍ期向Ｇ１期过渡并不是必需的，可能还有别的蛋白质参与；（３）采用药物阻断的方法同步化细胞，对细胞的生理、生化活动有潜在的影响。

Objective: Cyclin B is first synthesized during S phase, accumulates to complexes with p34cdc2 as cells approach the G2 to M transition, and is abruptly degraded during mitosis. However, early G1 phase HeLa cells obtained by releasing the M phase cells (treated by nocodazole) have cyclin B1 protein, so it is necessary to further study the role of cyclin B in M→G1 transition. Methods: Two types of methods were used to synchronize HeLa G1 phase cells, i.e, by releasing M phase cells (arrested by nocodazole) and by centrifugal elutriation. Their cyclin B1 protein levels were detected by Western blotting analysis. Results: There are cyclin B1 protein in the G1 phase cells obtained by releasing M phase cells, but the cyclin B1 was undetectable from the G1 cells collected by centrifugal elutriation. Conclusion: (1) Nocodazole can inhibit cyclin B1 degradation at the metaphaseanaphase transition;(2) The degradation of cyclin B1 is not essential for the metaphaseanaphase transition of HeLa cells; (3) Drugs that used to synchronize cells may have potential effect on the cell physiology.