Fig. 7

Schematic illustration describing HBx mediated miR-122 suppression enhances hepatoblastoma cell proliferation through cyclin G1/p53 axis. Normally miR-122 enhances p53 activity through down-regulation of its target protein cyclin G1 that forms a complex with PP2A phosphatase and enhances MDM2 activity to inhibit p53. HBx protein of HBV induces down regulation of miR-122 which up regulates cyclin G1 expression. Since cyclin G1 is a negative regulator of p53, up regulated cyclin G1 reduces the expression of p53. As a result expression of p21, which is specifically modulated by p53, is also reduced. Reduced expression of p21 releases the cells from G1 arrest thus facilitating cells for proliferation