title: Regulation of hepatitis B virus replication by the ras-mitogen-activated protein kinase signaling pathway.
abstract: The replication of hepatitis B virus (HBV) can be regulated by a variety of factors, including hormones, growth factors, and cytokines. However, the molecular mechanisms of these regulations are largely unknown. Ras is a small GTPase that responds to many of these external stimuli. In this study, we investigated the possible effect of Ras on the replication of HBV. Our results indicated that activated Ras could suppress the replication of HBV in both Huh7 and HepG2 cells. This suppression was independent of the X protein and most likely occurred at the transcriptional level. Deletion-mapping analysis of the HBV core promoter and its upstream ENI and ENII enhancers revealed multiple elements responsive to activated Ras. This suppression of HBV replication by activated Ras was apparently mediated by the mitogen-activated protein (MAP) kinase pathway, as it was accompanied by activation of ERK1/2 and abolished by the MEK1/2 inhibitor U0126. Our results thus indicate that external stimuli may suppress HBV replication through the Ras-MAP kinase pathway.
authors.affiliation: Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Johnson
authors.forename: Jing-hsiung
authors.initials: JH
authors.lastname: Ou
mesh_terms: D004279:DNA, Viral / Q000096:biosynthesis; D015967:Gene Expression Regulation, Viral; D006515:Hepatitis B virus / Q000502:physiology*; D006801:Humans; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism; D014407:Tumor Cells, Cultured; D054334:Viral Regulatory and Accessory Proteins; D014779:Virus Replication; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; C482128:MAP2K2 protein, human; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; D018631:ras Proteins