华支睾吸虫ATP合酶b亚基模拟亚细胞定位与细胞周期的关系

Subcellular Mimical Localization of the ATP Synthase B Subunit from Clonorchis sinensis under Different Conditioins of Cell Cycling

目的了解华支睾吸虫ATP合酶b亚基(CsATP-synt_B)核定位序列(NLS)介导该蛋白进入细胞核与细胞周期的关系,及该蛋白对自身和宿主同源基因表达的影响。方法将已构建的CsATP-synt_B与绿色荧光蛋白(GFP)融合表达质粒(pEGFP-N1-CsATP-synt_B)转染Hela细胞,转染细胞经同步化处理后,在激光共聚焦显微镜下观察在不同细胞周期相,细胞不同部位的荧光分布。流式细胞技术检测该融合蛋白表达量的变化,并通过半定量RT-PCR分析不同细胞周期相CsATP-synt_B和Hela细胞同源基因的表达。结果转染细胞经同步化处理后,流式细胞检测结果显示,空载体pEGFP-N1在G0/G1期Hela细胞中的表达量明显下降,而pEGFP-N1-CsATP-synt_B在该时期表达量呈上升趋势;在其他细胞周期时相,两者的荧光表达量的变化趋势相似。显微镜观察发现,在G0/G1期、S期和G2/M期CsATP-synt_B集中在线粒体表达,G1/S期细胞核内见绿色荧光,且多数细胞的绿色荧光集中见于核仁。在不同的细胞周期,半定量RT-PCR分析结果显示,该重组蛋白进入细胞核后,目的基因CsATP-synt_B和人源性ATP-synt_B(Ho-moATP-synt_B)mRNA的表达均呈上升趋势,CsATP-synt_B上升幅度较大,但两者的表达变化趋势一致。结论 CsATP-synt_B在G1/S期进入细胞核,受细胞能量需求和细胞周期的调控。

Objective To investigate the subcellular localization of ATP synthase b subunit from Clonorchis sinensis under different conditions of Hela cell cycling, and the effect of this protein on the expression of its encoding-gene and homologous host genes. Methods pEGFP-N1-CsATP-synt_B and the vector pEGFP-N1 were transfected into Hela cells, respectively. Transfected cells were synchronized in G0/G1 by serum starvation, G1/S, S cells by double thymidine block, and G2/M cells by thymidine-Nocodozale block. After synchronization, the subcellular localization of the expressed fusion protein was observed with a laser confocal microscope. The expression level of this fusion protein in cells was detected by flow cytometry （FCM）. The expression of CsATP-synt_B and HomoATP-synt_B in different cell cycle phases accessed by RT-PCR. Results FCM results indicated that in the G0/G1 phase the expression of pEGFP-N1 vector was decreased significantly, while pEGFP-N1-CsATP-synt_B expression showed an upward trend. In the other phases of cell cycle, the protein expression was similar in the above two kinds of plasmids. The intact CsATP-synt_B was expressed in mitochondria in the G0/G1, S, and G2/M phases and nucleus during G1/S phase. After the fusion proteins entered the nucleus, the mRNA expression of CsATP-synt_B and HomoATP-synt_B increased significantly. Conclusion CsATP-synt_B can be expressed in the nucleus during G1/S phase, and regulated by the cell cycle and energy requirements.