Objective   To construct the RNA interference eukaryotic expression vector targeting human centromere protein-I (CENP-I) and to observe its effect on the growth of human embryo kidney 293 cells (HEK 293).    Methods   The expression vectors of pGenesil-1/CENP-I-siRNA-1. pGenesil-1/CENP-I-siRNA-2 and pGenesil-1/CENP-I-siRNA-3 were constructed by gene recombination and then were transfected into the HEK293 cells by liposome

. The expressions of CENP-I at the protein and mRNA levels were detected by Western blotting and fluorescence quality PCR (FQ-PCR). The effective vector and the best transfection time were selected. The growth and the cell cycle of the transfected cells were assessed by MTT assay and flow cytometry. Giemsa was used to stain the transfected cells to calculate the mitotic index.    Results   Sequence-specific siRNAs targeting CENP-I significantly down-regulated the expression of CENP-I in HEK293 cells. The recombinant plasmid of pGenesil-1/CENP-I-siRNA-3 was the effective vector. After transfecting for 72 h the best inhibited efficiency was achieved. In CENP-I-siRNA transfected cells

the rate of cell growth was decreased markedly. Cells at G

2

/M phase and the mitotic index were increased conspicuous compared with the cells transfected with the blank vector or untransfected.    Conclusion   Down-regulation of CENP-I in HEK293 cells by sequence specific siRNA delays the cell growth and postpones the cell division.