Dynamic control of hepatitis B virus replication: contributions of hypoxia-inducible factor 1 and autophagy Nicholas Joseph Duchemin Michael Bouchard, Ph.D. Chronic hepatitis B virus (HBV) infection is the leading cause of primary liver cancer. Understanding the cellular pathways that contribute to the control of HBV replication is central to understanding the development of HBV-associated disease progression. The multifunctional HBV protein, HBx, has been linked to the modulation of a variety of cellular-signaling pathways and is thought to play a role in the progression of HBV-associated disease. HBx has previously been shown to stabilize hypoxia- inducible factor 1alpha (HIF1alpha), but the contribution of HIF1alpha to the HBV lifecycle remains unknown. HBx has also been shown to increase rates of early-stage autophagic flux, which contributes to progression of HBV-genome replication; however, the specific contributions of late-stage autophagy on HBV replication remain unknown. We therefore determined the role of both HIF1 and autophagy in control of HBV replication. We observed that HIF1alpha is a factor that enhances HBV mRNA levels, genome replication, and core particle levels. These HIF1-mediated stimulatory effects were observed when HIF1alpha was introduced via expression vectors or stabilized pharmacologically. Attenuating the transactivation ability of HIF1 blocked the positive effect of HIF1 on HBV mRNAs and HBV DNA. Although HBx expression resulted in an accumulation ofearly-stage, autophagy markers, HBx did not effect the levels of late-stage autophagy markers; however, blocking autophagy at both early and late stages resulted in decreased viral replication. Our studies have identified novel pathways that regulate HBV replication in primary hepatocytes. HBV-mediated changes in HIF1-signaling pathways and autophagy may connect chronic HBV infection to the development of HBV- associated disease progression.