Objective  To construct an adenovirus vector that expresses small interfering RNA (siRNA) against FoxO1 to shutdown its gene expression.   Methods  The FoxO1 template DNA sequence was designed by using online tools. Then the sense and antisense siRNA oligonucleotide templates were chemically synthesized

annealed and cloned into adenoviral shuttle vector pAdTrack-CMV. The recombinant adenovirus vector pAd-si-FoxO1 was obtained by homologous recombination with pAdTrack-CMV and pAdeasy-1 in bacteria BJ5183. The recombined adenovirus was produced in 293 cells and subsequently infected HepG2 cells. The FoxO1 protein levels were detected by Western blot.   Results  The adenovirus vector expressing small interfering RNA for FoxO1 gene could specifically shutdown the endogenous FoxO1 protein in HepG2 cells.    Conclusion  The pAd-si-FoxO1 can effectively downregulate FoxO1 expression in HepG2 cell line.