中文摘要：

番茄丛矮病毒的P19蛋白不仅是一个重要的病毒致病因子,而且还可作为RNA干扰（RNAi）的抑制子.这种作用是通过限制细胞内的小RNA,比如小干扰RNA（siRNAs）和微RNA（miRNAs）来实现.但是目前对P19蛋白在哺乳动物细胞上的作用还未见报道.构建了一株p19稳定表达的293细胞系,即293-p19.流式细胞仪分析发现在293细胞中过量表达P19蛋白可显著引发细胞周期的G2/M阻滞.细胞增殖实验显示,293-p19细胞的DNA复制及细胞生长均受到显著的抑制.此外,研究还发现p19可使人胚肾293细胞内的细胞周期调控子的表达谱发生改变.其中包括上调cyclinA1,CDK2,CDK4,CDK6,p18,cyclinD2,p19INK4d和E2F1,及下调p15,cyclinA,cyclinB1和cyclinE1的表达.上述研究结果提示,p19有可能靶向多个G2/M调控蛋白从而引发细胞的G2/M阻滞.

英文摘要：

Besides its function as a pathogenicity determinant, the Tombusvirus P19 also serves as a suppressor of RNA interference （RNAi） by sequestering intracellular small RNAs such as the small interfering RNAs （siRNAs） and microRNAs （miRNAs）. However, the effect of P19 on mammalian cells has not been evaluated before. A human embryonic kidney 293 cell line that stably expressed p19 （HEK293-p19） was generated. Flow cytometric analysis revealed that over-expression of P19 caused a significant accumulation of G2/M phase cells. Cell proliferation assays demonstrated a reduced DNA replication and cell growth in HEK293-p19 cells. Moreover, p19 altered the expression profiles of a number of cell cycle regulators in HEK293 cells, such as upregulation of cyclin A1, CDK2, CDK4, CDK6, p18, cyclin D2, p19INK4d and E2F1, and downregulation of p15, cyclin A2, cyclin B1 and cyclin E1. Thus, the data strongly indicate that p19 might influence multiple G2/M regulators to cause G2/M arrest.