title: Differential regulation of hepatitis B virus core protein expression and genome replication by a small upstream open reading frame and naturally occurring mutations in the precore region.
abstract: Hepatitis B virus (HBV) transcribes two subsets of 3.5-kb RNAs: precore RNA for hepatitis B e antigen (HBeAg) expression, and pregenomic RNA for core and P protein translation as well as genome replication. HBeAg expression could be prevented by mutations in the precore region, while an upstream open reading frame (uORF) has been proposed as a negative regulator of core protein translation. We employed replication competent HBV DNA constructs and transient transfection experiments in Huh7 cells to verify the uORF effect and to explore the alternative function of precore RNA. Optimized Kozak sequence for the uORF or extra ATG codons as present in some HBV genotypes reduced core protein expression. G1896A nonsense mutation promoted more efficient core protein expression than mutated precore ATG, while a +1 frameshift mutation was ineffective. In conclusion, various HBeAg-negative precore mutations and mutations affecting uORF differentially regulate core protein expression and genome replication.
authors.affiliation: Liver Research Center, Rhode Island Hospital, Warren Alpert School of Medicine, Brown University, Providence, RI, USA; Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zong
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Haodi
authors.initials: H
authors.lastname: Jia
authors.affiliation: Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ye
authors.affiliation: Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Jiming
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Liver Research Center, Rhode Island Hospital, Warren Alpert School of Medicine, Brown University, Providence, RI, USA.
authors.forename: Jack R
authors.initials: JR
authors.lastname: Wands
authors.affiliation: Liver Research Center, Rhode Island Hospital, Warren Alpert School of Medicine, Brown University, Providence, RI, USA; Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Shuping
authors.initials: S
authors.lastname: Tong
authors.affiliation: Liver Research Center, Rhode Island Hospital, Warren Alpert School of Medicine, Brown University, Providence, RI, USA. Electronic address: ji_su_li_md@brown.edu.
authors.forename: Jisu
authors.initials: J
authors.lastname: Li
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D018389:Codon, Nonsense / Q000235:genetics; D004261:DNA Replication / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D016368:Frameshift Mutation / Q000235:genetics; D015967:Gene Expression Regulation, Viral / Q000235:genetics*; D006512:Hepatitis B Core Antigens / Q000096:biosynthesis* / Q000235:genetics*; D006513:Hepatitis B e Antigens / Q000096:biosynthesis / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000821:virology; D006801:Humans; D016366:Open Reading Frames / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics; D014758:Viral Core Proteins / Q000096:biosynthesis* / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics
chemical_list: D018389:Codon, Nonsense; D004279:DNA, Viral; D006512:Hepatitis B Core Antigens; D006513:Hepatitis B e Antigens; D011498:Protein Precursors; D014758:Viral Core Proteins
keywords: Core protein; Genome replication; Hepatitis B e antigen; Hepatitis B virus; Precore RNA; Precore mutant; Pregenomic RNA; Translational control