Objective   To construct the prokaryotic expression vector of BC047440 gene and to observe the effect of different concentrations of this recombinant protein on proliferation of human HepG2 cells.  Methods   Total RNA was extracted from HepG2 cells. BC047440 gene fragments were amplified from the total RNA by RT-PCR. The PCR product was cloned into pMD19-T vector and sequenced. The confirmed BC047440 cDNA was cloned into plasmid pET-28a (+) and transformed into E.coli BL21 where expression of BC047440 proteins was induced by IPTG. The expression product of BC047440 protein was identified by SDS-PAGE. Recombinant BC047440 protein was extracted and its effect on proliferation of HepG2 cells was detected by MTT assay and cytometry

respectively. Effect of recombinant BC047440 protein on expression of Ki67 protein in HepG2 cells was detected by Western blotting.  Results   The prokaryotic expression vector was constructed. The BC047440 gene was cloned

identified

and purified. The proliferation rate of HepG2 cells was 124.0%

136.1%

and 126.6% respectively 48 h after BC047440 protein was transformed into HepG2 cells at the concentration of 1.0

10.0

and 20.0  μg/ml respectively (P0.05). Cytometry showed that the proliferation constant of HepG2 cells was 26.1 in control group and 48.6 in experimental group (P0.05). The relative expression of Ki67 protein was 0.317±0.062 in experimental group and 0.177±0.037 in control group (P0.05).  Conclusion   Recombinant BC047440 protein can directly promote the proliferation and expression of Ki67 protein and may be a new protein that can stimulate the proliferation of HCC cells.