MicroRNAs may solve the mystery of chronic hepatitis B virus infection

Figure 2 The biogenesis of human cellular microRNAs and the mechanism of the alteration hepatitis B virus gene transcription and replication. For simplicity, not all participators are shown. A: The biogenesis of microRNAs (miRNAs); B: The mechanism of cellular miRNAs regulates hepatitis B virus (HBV) gene transcription and replication can be direct and indirect. Cellular miRNAs can target to HBV transcripts (HBV surface antigen mRNA, HBV x mRNA, DNA polymerase mRNA, etc.), causing the alteration of HBV expression. Cellular miRNAs can also target to the mRNAs of a number of key regulatory proteins (liver-enriched transcription factors, nuclear receptors, heme-oxygenase-1, DNA methyltransferases, etc.) in the process of HBV transcription and replication. Consequently, the amount of these proteins was changed, and the HBV gene transcription and replication were altered. RISC: RNA-induced silencing complex. Pol: Polymerase.