微丝重组对细胞增值作用的研究

用罗丹明－鬼笔环肽（ｒｈｏｄａｍｉｎｅ－ｐｈａｌｌｏｉｄｉｎ）显示微丝（ｍｉｃｒｏｆｉｌａｍｅｎｔｓ，ＭＦ）的荧光染色法对Ｇ期小鼠Ｃ３Ｈ１０Ｔ１／２成纤维细胞向Ｓ期过渡过程中，ＭＦ结构的变化及ＭＦ重组对ＤＮＡ合成的影响进行了研究，Ｇ期细胞在血清刺激１ｈ后ＭＦ解聚，３ｈ后重新组装，并恢复原来的分布。我们发现细胞松弛素Ｂ（ｃｙｔｏｃｈａｌａｓｉｎＢ，ＣＢ）使ＭＦ解聚并与蛋白激酶Ｃ（ｐｒｏｔｅｉｎｋｉｎａｓｅＣ，ＰＫＣ）激活剂──佛波酯（ｐｈｏｒｂｏｌｅｓｔｅｒ，ＴＰＡ）同样可促进Ｇ期细胞提前进入Ｓ期，促进ＤＮＡ合成，但ＴＰＡ和ＣＢ的刺激作用必需依赖于血清的存在，而ＰＫＣ抑制剂Ｈ７则阻断Ｇ期细胞进入Ｓ期，ＭＦ稳定剂ｐｈａｌｌｏｉｄｉｎ对ＤＮＡ合成具有一定的抑制作用，实验结果表明，Ｇ期细胞向Ｓ期过渡的早期阶段存在ＭＦ重组过程，ＣＢ促使Ｇ细胞ＭＦ解聚并可促进ＤＮＡ合成，提示ＭＦ重组是Ｇ期细胞向Ｓ期过渡的一个重要的早期事件。

THE EFFECTS OF MICROFILAMENT REORGANIZATION ON THE CELL PROLIFERATION

This experiment was conducted byusing cultured mouse C3H10T1/2 fibroblasts for studing the role of microfilament(MF)reorganization in the regualation progression from G0 to S phase. Us ing a fluorescence probe(rhodamine-phalloidin) specific for F-actin,it was shown that in G0 cells stimulated by fetal calf serum for 1 hr,the MF depolymerized. But the distribution of MF was restored after stimulation with fetal calf serum for 3 hrs,DNA synthesis was elevated by pre treatment of Gn cells with the stimulator of protein kinase C(PKC)-TPA for short time,However,at the periphery of cells MF bundles were depolymerized after treatment with TPA. The inhibitor of PKC-H7 inhibited not only DNA synthesis,but also the process of MF depolymerization in the early stage of the progression from G0 to S phase,H7 treatment of cells resulted in a complete blockage of the progression from G0 to S phase. It is noteworthy that DNA synthesis by fetal calf serum was significantly enhanced by pretreatment of G0 cells with the MF destroying agent-cytochalasin B(3 mg/L) for 2 hrs,Therefore,the process of MF reorganization may be one of the important events in the transition from G0 to S phase have be proposed in this paper.