Study of the effect and mechanism of spastic paraplegia 21 protein on the replication of hepatitis B virus / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the effect of human spastic paraplegia 21 protein (SPG21) on the replication of hepatitis B virus(HBV) and its regulatory mechanism.</p><p><b>METHODS</b>HBV infectious clone pHBV1.3 and its promoter pHBV-Luc were transfected respectively into HepG2 cells with SPG21 of different concentrations, HBsAg and HBeAg in the supernatants were measured by enzyme linked immunosorbent assay (ELISA), expression of HBV core mRNA and protein were detected by RT-PCR and western blot, covalently closed circular DNA(ccc DNA) levels were measured by real-time PCR, and HBV promoter activity was measured by luminometer fluorescence detector.</p><p><b>RESULTS</b>Expression of HBsAg, HBeAg, HBV core protein and cccDNA were upregulated by SPG21 as well as HBV promoter activity in a dose-dependent approach. The activity of HBV promoter increased to 1.63, 3.09 and 4.66 times in HepG2 cells treated with 50mug/ml, 100mug/ml and 200mug/ml SPG21 respectively during 48 hour-treated ( P less than 0.05), as compared to the control group.</p><p><b>CONCLUSIONS</b>SPG21 can enhance the replication of HBV in HepG2 cells.</p>

Effect of hepatitis B virus X gene on the expression of spastic paraplegia 21 / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the effect of hepatitis B virus(HBV) X gene on the expression of SPG21.</p><p><b>METHODS</b>The expressions of SPG21 mRNA and protein in HepG2 and HepG2.2.15 cells were tested by RT-PCR and western blot. HepG2 cells were co-transfected with reporter plasmid pGL3-SPG21 and plasmids carrying individual genes of HBV, the luciferase activity was measured and the expressions of SPG21 were detected by RT-PCR and western blot.</p><p><b>RESULTS</b>The expressions of SPG21 mRNA and protein were higher in HepG2.2.15 cells than in HepG2 cells (0.36+/-0.06 vs 0.21+/-0.05, P value is less than 0.05). The activity of SPG21 in HepG2 cells transfected with pCMV-X was higher (875+/-27 vs 67+/-12, P value is less than 0.01) as compared to blank control group (transfected with pCMV-tag2B). HBV X gene enhanced SPG21 gene promoter activity, SPG21 mRNA expression and SPG21 protein production in HepG2 cells in a dose-dependent manner.</p><p><b>CONCLUSION</b>HBV X gene can specially activate SPG21 expression.</p>