盘基网柄菌突变型细胞allC的细胞周期异常

Cell Cycle Abnormality in Dictyostelium discoideum allC Mutant Cell Line

研究盘基网柄菌(Dictyostelium discoideum)细胞周期的相关问题可以为真核生物细胞周期调控研究提供理论基础。细胞计数和细胞倍增时间计算的结果表明,突变allC细胞的倍增时间为2.36 h,仅为KAx-3细胞倍增时间的1/3。进一步利用流式细胞术测定两种细胞的细胞周期,并结合实时荧光定量PCR技术测定cycB1和cdk1基因的相对表达量的比值,我们发现,培养16 h的allC细胞处于G2期的数目(1.51%)显著少于KAx-3细胞(16.61%)(P<0.05)。allC细胞和KAx-3细胞的细胞周期素B1(cyclinB1,cycB1)基因相对表达量分别是2.5和0.24(P<0.05),两者相差10倍。两种类型细胞中处于G2期的细胞数目差异十分明显,cycB1的相对表达量也存在显著差异,表明cycB1的过表达可能在一定程度上影响allC细胞的细胞周期正常的调控机制,与突变细胞的G2期异常有一定关系,但具体机制仍需进一步探究。

Study on Dictyostelium discoideum cell cycle can provide theoretical foundation for research of the eukaryotic cell cycle regulation. In this study, the cell counting and cell doubling time calculation indicated that the allC mutant doubling time was 2.36 h, only one third of that of KAx-3 cells. To search for the reason of shortened allC mutant doubling time, the function of cyclin B1, cell cycle of mutant cells and wild cells were studied by flow cytometry and real time-quantitative PCR. After cultured for 16 hours, the number of the mutant allC cells （1.51%） in the G2 phase was significantly less than that of KAx-3 cells （16.61%）（P〈0.05）. The relative expression level of cyclin B1 in allC mutant and KAx-3 cells were 2.5 and 0.24, respectively. It has demonstrated that the G2 phase of allC mutant was obviously shorter than that of KAx-3 cells, so was the relative expression level of cyclin B1 which was related closely to G2 phase regulation. Our results suggest that the overexpression of cyclin B1 in allC mutant may affect the normal cell cycle regulation to some extent, and it contributes to G2 phase abnormality.