The hepatitis B virus and its DNA polymerase: The prototype three-D virus

Hirschman, Shalom Z.

doi:10.1007/bf00226820

Cited by 8 publications

(3 citation statements)

References 164 publications

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“…Though not directly essential to HBV replication, the HBeAg is believed to have important immunomodulatory functions, allowing for persistent and chronic infections (19)(20)(21)(22). The viral polymerase, HBpol, is the largest protein expressed by HBV, coming in at 750 AA; it is a DNA polymerase capable of conventional DNA synthesis as well as reverse transcription and RNase H activity (8,(23)(24)(25)(26)(27). The terminal protein (TP) domain of HBpol (AA: 1-177) triggers the encapsidation of the HBV pregenomic RNA (pgRNA)…”

Section: The Hbv Genomementioning

confidence: 99%

Proteomic Analysis of Nuclear Hepatitis B Virus Relaxed Circular DNA-Associated Proteins Identifies UV-Damaged DNA Binding Protein as a Host Factor Involved in Covalently Closed Circular DNA Formation

Marchetti

Zhang

Kim

et al. 2022

J Virol

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Hepatitis B virus (HBV) utilizes host DNA repair mechanisms to convert viral relaxed circular DNA (rcDNA) into a persistent viral genome, the covalently closed circular DNA (cccDNA). To identify said host factors involved in cccDNA formation, we developed an unbiased approach to discover proteins involved in cccDNA formation by precipitating nuclear rcDNA from induced HepAD38 cells and identifying the co-precipitated proteins by mass spectrometry. The DNA damage binding protein 1 (DDB1) surfaced as a hit, coinciding with our previously reported shRNA screen in which shRNA-DDB1 in HepDES19 cells reduced cccDNA production. DDB1 binding to nuclear rcDNA was confirmed in HepAD38 cells via ChIP-qPCR. DDB1 and DNA damage binding protein 2 (DDB2) form the UV-DDB complex and the latter senses DNA damage to initiate the global genome nucleotide excision repair (GG-NER) pathway. To investigate the role of DDB complex in cccDNA formation, DDB2 was knocked out in HepAD38 and HepG2-NTCP cells. In both knockout cell lines, cccDNA formation was stunted significantly, and in HepG2-NTCP-DDB2 knockout cells, downstream indicators of cccDNA such as HBV RNA, HBcAg, and HBeAg were similarly reduced. Knockdown of DDB2 in HBV-infected HepG2-NTCP cells and primary human hepatocytes (PHH) also resulted in cccDNA reduction. Trans-complementation of wild type DDB2 in HepG2-NTCP-DDB2 knockout cells rescued cccDNA formation and its downstream indicators. However, ectopic expression of DDB2 mutants deficient in DNA-binding, DDB1-binding, or ubiquitination failed to rescue cccDNA formation. Our study thus suggests an integral role of UV-DDB, specifically DDB2, in the formation of HBV cccDNA. IMPORTANCE Serving as a key viral factor for chronic hepatitis B virus (HBV) infection, HBV covalently closed circular DNA (cccDNA) is formed in the cell nucleus from viral relaxed circular DNA (rcDNA) by hijacking host DNA repair machinery. Previous studies have identified a handful of host DNA repair factors involved in cccDNA formation through hypothesis-driven research with some help from RNAi screening and/or biochemistry approaches. To enrich the landscape of tools for discovering host factors responsible for rcDNA-to-cccDNA conversion, we developed an rcDNA immunoprecipitation paired mass spectrometry assay, which allowed us to pull down nuclear rcDNA in its transitional state to cccDNA and observe the associated host factors. From this assay we discovered a novel relationship between the UV-DDB complex and cccDNA formation, hence, providing a proof-of-concept for a more direct discovery of novel HBV DNA-host interactions that can be exploited to develop new cccDNA-targeting antivirals.

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Section: The Hbv Genomementioning

confidence: 99%

Proteomic Analysis of Nuclear Hepatitis B Virus Relaxed Circular DNA-Associated Proteins Identifies UV-Damaged DNA Binding Protein as a Host Factor Involved in Covalently Closed Circular DNA Formation

Marchetti

Zhang

Kim

et al. 2022

J Virol

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“…HBeAg is a form of HBcAg secreted in blood, and is usually an accurate index of viral load. 12 – 14 The polymerase, a DNA-dependent DNA polymerase, is involved in reverse transcription for viral replication 15 – 17 and is research target for the development of drugs against HBV. 5 , 18 – 20 …”

Section: Genome Organization and Genotypesmentioning

confidence: 99%

The Molecular and Structural Basis of HBV-resistance to Nucleos(t)ide Analogs

Gupta

Goyal

et al. 2014

JCTH

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Infection with hepatitis B virus (HBV) is a worldwide health problem. Chronic hepatitis B can lead to fibrosis, liver cirrhosis, and hepatocellular carcinoma (HCC). Management of the latter two conditions often requires liver transplantation. Treatment with conventional interferon or pegylated interferon alpha can clear the virus, but the rates are very low. The likelihood, however, of viral resistance to interferon is minimal. The main problems with this therapy are the frequency and severity of side effects. In contrast, nucleos(t)ide analogs (NAs) have significantly lower side effects, but require long term treatment as sustained virological response rates are extremely low. However, long term treatment with NAs increases the risk for the development of anti-viral drug resistance. Only by understanding the molecular basis of resistance and using agents with multiple sites of action can drugs be designed to optimally prevent the occurrence of HBV antiviral resistance.

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“…The viral core contains a 3200 nucleotide-long, open circular partially singlestranded DNA, a DNA polymerase, and a protein kinase (for reviews, see Robinson, 1977;Hirschman, 1979;Tiollais et al, 1981).…”

Section: Introductionmentioning

confidence: 99%

Properties of Hepatitis B e Antigen Synthesized by Rat Cells Transfected with Circular Viral DNA

Serrano

Hirschman

1984

Journal of General Virology

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SUMMARYTransfection of Buffalo rat liver cells with closed circular hepatitis B virus DNA resulted in the synthesis of both hepatitis B e and surface antigens. A 14000 tool. wt. peptide bearing hepatitis B e antigenic determinants was isolated from cell culture fluids. Native hepatitis B e antigen was present in multimeric forms in the cell culture fluids and was associated with protein phosphokinase activity. The multimeric forms of hepatitis B e antigen may serve both structural and enzymic functions for the hepatitis B virion with its small genome.

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The hepatitis B virus and its DNA polymerase: The prototype three-D virus

Cited by 8 publications

References 164 publications

Proteomic Analysis of Nuclear Hepatitis B Virus Relaxed Circular DNA-Associated Proteins Identifies UV-Damaged DNA Binding Protein as a Host Factor Involved in Covalently Closed Circular DNA Formation

Proteomic Analysis of Nuclear Hepatitis B Virus Relaxed Circular DNA-Associated Proteins Identifies UV-Damaged DNA Binding Protein as a Host Factor Involved in Covalently Closed Circular DNA Formation

The Molecular and Structural Basis of HBV-resistance to Nucleos(t)ide Analogs

Properties of Hepatitis B e Antigen Synthesized by Rat Cells Transfected with Circular Viral DNA

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