title: Transcription of hepatitis B virus covalently closed circular DNA is regulated by CpG methylation during chronic infection.
abstract: The persistence of hepatitis B virus (HBV) infection is maintained by the nuclear viral covalently closed circular DNA (cccDNA), which serves as transcription template for viral mRNAs. Previous studies suggested that cccDNA contains methylation-prone CpG islands, and that the minichromosome structure of cccDNA is epigenetically regulated by DNA methylation. However, the regulatory effect of each CpG island methylation on cccDNA activity remains elusive. In the present study, we analyzed the distribution of CpG methylation within cccDNA in patient samples and investigated the impact of CpG island methylation on cccDNA-driven virus replication. Our study revealed the following observations: 1) Bisulfite sequencing of cccDNA from chronic hepatitis B patients indicated that CpG island I was seldom methylated, 2) CpG island II methylation was correlated to the low level of serum HBV DNA in patients, and in vitro methylation studies confirmed that CpG island II methylation markedly reduced cccDNA transcription and subsequent viral core DNA replication, 3) CpG island III methylation was associated with low serum HBsAg titers, and 4) Furthermore, we found that HBV genotype, HBeAg positivity, and patient age and liver fibrosis stage were also relevant to cccDNA CpG methylation status. Therefore, we clearly demonstrated that the status of cccDNA methylation is connected to the biological behavior of HBV. Taken together, our study provides a complete profile of CpG island methylation within HBV cccDNA and new insights for the function of CpG methylation in regulating HBV cccDNA transcription.
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Richeng
authors.initials: R
authors.lastname: Mao
authors.affiliation: Institute for Biotechnology and Virology Research, Department of Microbiology and Immunology, Drexel University College of Medicine, Doylestown, Pennsylvania, United States of America.
authors.forename: Ran
authors.initials: R
authors.lastname: Yan
authors.affiliation: Institute for Biotechnology and Virology Research, Department of Microbiology and Immunology, Drexel University College of Medicine, Doylestown, Pennsylvania, United States of America.
authors.forename: Dawei
authors.initials: D
authors.lastname: Cai
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Haoxiang
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Yaoyue
authors.initials: Y
authors.lastname: Kang
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Jinyu
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Yuxian
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Institute for Biotechnology and Virology Research, Department of Microbiology and Immunology, Drexel University College of Medicine, Doylestown, Pennsylvania, United States of America.
authors.forename: Haitao
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China; Key Laboratory of Medical Molecular Virology (MOH & MOE), Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Jiming
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000367:Age Factors; D018899:CpG Islands; D019175:DNA Methylation; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics*; D044127:Epigenesis, Genetic; D005260:Female; D015967:Gene Expression Regulation, Viral; D016679:Genome, Viral; D005838:Genotype; D056945:Hep G2 Cells; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006513:Hepatitis B e Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000097:blood / Q000150:complications / Q000276:immunology / Q000821:virology; D054884:Host-Pathogen Interactions; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood / Q000209:etiology / Q000276:immunology / Q000821:virology; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D014158:Transcription, Genetic; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens