【摘要】 RC3细胞是一种用真核表达载体1^CaM转染NIH 3T3细胞建成的可调钙凋素（Calmodulin,CaM）高表达细胞模型。通过分子杂交及蛋白免疫印迹方法证实在地塞米松（Dexamethasome,DXM）作用下,RC3细胞可高表达CaM。CaM的过表达使G₁期细胞减少,S期细胞增加;CaM拮抗剂三氟拉嗪（trifluoperazine,TFP）则使G₁期细胞增加,S期细胞减少。高表达CaM使细胞分裂指数提高,G₂期细胞减少,有丝分裂前期细胞增加,M中期细胞比例下降。而TFP处理则使分裂指数下降,G₂期细胞增加,M前期细胞减少,M中期细胞增加。实验结果表明CaM在G₁/S、G₂/M和M中期/M后期3个位点上对细胞周期进行调控;通过加速G₁至S期,G₂至M期和M中期至M后期的进程,使细胞倍增时间缩短,促进细胞增殖。本工作表明,RC3细胞作为CaM表达可调细胞模型,是研究细胞周期调控的有力工具。更多还原

【Abstract】 In order to study the role of calmo-dulin (CaM) in the cell cycle, RC 3 cells earring the CaM expression vectors which was constructed by joining the CaM cDNA with a plasmid of mouse mammary tumor virus (MMTV), were used in this experiment. The CaM expression vectors transcription is regulated by a dexamethasone (DXM) inducible MMTV LTR promoter. Upon addition of DXM, cells have transiently increased CaM mRNA and protein levels. Increased CaM caused a acceleration of proliferation. Flow cytometric analysis showed that progression though G1, G2 and metaphase was accelerated by increase in CaM levels, while treatment with the CaM antagonisttrifluoperazine (TFP) blocked cell cycle progression at G1/S boundary and during G2/M and metaphase. The studies have shown that CaM is important in controlling progression at three points in the cell cycle. (1) The G1/S boundary to permit the initiation of DNA synthesis; (2) The G2/M boundary to permit the initiation of mitosis; (3) At the metapha-se/anaphase transition of mitosis to permit chromosome segration and the completion of mitosis. This study indicates that the RC 3 cell is a useful experimental cell model for studing the effect of a transient increase of intracellular CaM levels on control of cell cycle.更多还原