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Proc Natl Acad Sci U S A. 2018 Aug 28;115(35):8829-8834. doi: 10.1073/pnas.1808319115. Epub 2018 Aug 13.

N6-methyladenosine modification of hepatitis B virus RNA differentially regulates the viral life cycle.

Author information

1
Division of infectious Diseases, School of Medicine, University of California, San Diego, La Jolla, CA 92093.
2
Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710.
3
Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10021.
4
Department of Biotechnology, Yonsei University, 03722 Seoul, South Korea.
5
Institute for Digestive Research, Digestive Disease Center, Department of Internal Medicine, College of Medicine, Soonchunhyang University, 04401 Seoul, South Korea.
6
Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Yuseong, 34114 Daejeon, South Korea.
7
HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY 10021.
8
Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065.
9
WorldQuant Initiative for Quantitative Prediction, Weill Cornell Medicine, New York, NY 10065.
10
Department of Medicine, Duke University Medical Center, Durham, NC 27710.
11
Division of infectious Diseases, School of Medicine, University of California, San Diego, La Jolla, CA 92093; asiddiqui@ucsd.edu.

Abstract

N6-methyladenosine (m6A) RNA methylation is the most abundant epitranscriptomic modification of eukaryotic messenger RNAs (mRNAs). Previous reports have found m6A on both cellular and viral transcripts and defined its role in regulating numerous biological processes, including viral infection. Here, we show that m6A and its associated machinery regulate the life cycle of hepatitis B virus (HBV). HBV is a DNA virus that completes its life cycle via an RNA intermediate, termed pregenomic RNA (pgRNA). Silencing of enzymes that catalyze the addition of m6A to RNA resulted in increased HBV protein expression, but overall reduced reverse transcription of the pgRNA. We mapped the m6A site in the HBV RNA and found that a conserved m6A consensus motif situated within the epsilon stem loop structure, is the site for m6A modification. The epsilon stem loop is located in the 3' terminus of all HBV mRNAs and at both the 5' and 3' termini of the pgRNA. Mutational analysis of the identified m6A site in the 5' epsilon stem loop of pgRNA revealed that m6A at this site is required for efficient reverse transcription of pgRNA, while m6A methylation of the 3' epsilon stem loop results in destabilization of all HBV transcripts, suggesting that m6A has dual regulatory function for HBV RNA. Overall, this study reveals molecular insights into how m6A regulates HBV gene expression and reverse transcription, leading to an increased level of understanding of the HBV life cycle.

KEYWORDS:

HBV reverse transcription; RNA methylation; epsilon loop; hepatitis B virus

PMID:
30104368
PMCID:
PMC6126736
DOI:
10.1073/pnas.1808319115
[Indexed for MEDLINE]
Free PMC Article

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