scholarly journals Reverse Transcriptase- and RNA Packaging Signal-Dependent Incorporation of APOBEC3G into Hepatitis B Virus Nucleocapsids

2008 ◽  
Vol 82 (14) ◽  
pp. 6852-6861 ◽  
Author(s):  
David H. Nguyen ◽  
Jianming Hu
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Reverse Transcriptase ◽  
Cytidine Deaminase ◽  
Rna Packaging ◽  
Packaging Signal ◽  
Independent Manner ◽  
Wide Range ◽  
B Virus ◽  
Rna Packaging Signal

ABSTRACT APOBEC3G (A3G) is a cytidine deaminase that can inhibit a wide range of retroviruses, including the para-retrovirus hepatitis B virus (HBV). The antiviral function of A3G depends on its incorporation into assembling viral particles. However, it remains enigmatic how A3G is specifically packaged into a variety of unrelated viruses. By adopting a native agarose gel electrophoresis assay that can specifically measure the levels of A3G incorporation into HBV nucleocapsids, we found that A3G is specifically packaged into replication-competent HBV nucleocapsids in a fashion that is dependent on both the viral reverse transcriptase (RT) and viral RNA packaging signal, ε. In contrast, A3G is not incorporated into empty capsids formed in the absence of RT or ε. We demonstrated that the packaged A3G was protected from protease digestion by the nucleocapsids, thus confirming its interior localization. We also showed that A3G could bind RT specifically in an RNA-independent manner, which may be responsible for mediating the specific incorporation of A3G into replication-competent nucleocapsids. Finally, we provide evidence that the N-terminal domain of A3G is required for packaging into HBV nucleocapsids.

scholarly journals The Duck Hepatitis B Virus Polymerase Is Activated by Its RNA Packaging Signal, ɛ

1998 ◽  
Vol 72 (7) ◽  
pp. 5789-5796 ◽  
Author(s):  
John E. Tavis ◽  
Brandon Massey ◽  
Yunhao Gong
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Reverse Transcription ◽  
Rna Packaging ◽  
Packaging Signal ◽  
Viral Polymerase ◽  
Duck Hepatitis B Virus ◽  
Duck Hepatitis ◽  
B Virus ◽  
Rna Packaging Signal

ABSTRACT The ɛ stem-loop at the 5′ end of the pregenomic RNA of the hepatitis B viruses is both the primary element of the RNA packaging signal and the origin of reverse transcription. We have previously presented evidence for a third essential role for ɛ, that of an essential cofactor in the maturation of the viral polymerase (J. E. Tavis and D. Ganem, J. Virol. 70:5741–5750, 1996). In this case, binding of ɛ to the polymerase is proposed to induce a physical alteration to the polymerase that is needed for it to develop enzymatic activity. Three lines of evidence employing duck hepatitis B virus supporting this hypothesis are presented here. First, an unusual DNA polymerase activity employing exogenous RNAs (thetrans reaction) that was originally discovered with recombinant duck hepatitis B virus polymerase expressed inSaccharomyces cerevisiae yeasts was shown to be an authentic property of the viral polymerase. The transreaction was found to be template-dependent reverse transcription of the exogenous RNA. The trans reaction occurred independently of the hepadnavirus protein-priming mechanism, yet it was still strongly stimulated by ɛ. This directly demonstrates a role for ɛ in activation of the polymerase. Second, the reverse transcriptase domain of the polymerase was shown to be physically altered following binding to ɛ, as would be expected if the alteration was required for maturation of the polymerase to an enzymatically active form. Finally, analysis of 15 mutations throughout the duck hepatitis B virus polymerase demonstrated that the ɛ-dependent alteration to the polymerase was a prerequisite for DNA priming, reverse transcription, and the trans reaction.

scholarly journals Inhibition of Hepadnavirus Reverse Transcriptase-ε RNA Interaction by Porphyrin Compounds

2007 ◽  
Vol 82 (5) ◽  
pp. 2305-2312 ◽  
Author(s):  
Li Lin ◽  
Jianming Hu
Keyword(s):  
Reverse Transcriptase ◽  
Protoporphyrin Ix ◽  
Rna Packaging ◽  
Packaging Signal ◽  
B Virus ◽  
Protein Priming ◽  
Rna Interaction ◽  
Iron Protoporphyrin ◽  
Rna Packaging Signal ◽  
Viral Reverse Transcription

ABSTRACT The hepatitis B virus (HBV) reverse transcriptase (RT) plays a multitude of fundamental roles in the viral life cycle and is the key target in the development of anti-HBV chemotherapy. We report here that the endogenous small molecule iron protoporphyrin IX (hemin) and several related porphyrin compounds potently blocked a critical RT interaction with the viral RNA packaging signal/origin of replication, called ε. As RT-ε interaction is essential for the initiation of viral reverse transcription, which is primed by RT itself (protein priming), the porphyrin compounds dramatically suppressed the protein-priming reaction. Further studies demonstrated that these compounds could target the unique N-terminal domain of the RT protein, the so-called terminal protein. Hemin and related porphyrin compounds thus represent a novel class of agents that can block HBV RT functions through a mechanism and target that are completely distinct from those of existing anti-HBV drugs.

scholarly journals Incorporation of deoxyribonucleotides and ribonucleotides by a dNTP-binding cleft mutated reverse transcriptase in hepatitis B virus core particles

Virology ◽  
2008 ◽  
Vol 370 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Hee-Young Kim ◽  
Hye-Young Kim ◽  
Jaesung Jung ◽  
Sun Park ◽  
Ho-Joon Shin ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Reverse Transcriptase ◽  
Virus Core ◽  
B Virus ◽  
Binding Cleft ◽  
Dntp Binding ◽  
Core Particles

scholarly journals Hepatitis B virus polymerase restricts LINE-1 retrotransposition

2021 ◽  
Author(s):  
Yasuo Ariumi
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Rna Binding ◽  
Rnase H ◽  
Ribonuclease H ◽  
Independent Manner ◽  
Cytoplasmic Rna ◽  
B Virus ◽  
Long Interspersed Element ◽  
L1 Retrotransposon

Long interspersed element-1 (LINE-1, L1) retrotransposon composes about 17% of the human genome. However, genetic and biochemical interactions between L1 and hepatitis B virus (HBV) remain poorly understood. In this study, we found that HBV restricts L1 mobility without inhibiting the L1 promoter activity. Notably, HBV polymerase (Pol) strongly inhibited L1 retrotransposition in a reverse transcriptase (RT)-independent manner. Indeed, the ribonuclease H (RNase H) domain was essential for inhibition of L1 retrotransposition. L1 ORF1p RNA-binding protein predominantly localized into cytoplasmic RNA granule termed P-body. However, HBV Pol sequestered L1 ORF1p from P-body and colocalized with L1 ORF1p in cytoplasm, when both proteins were co-expressed. Altogether, HBV Pol seems to restrict L1 mobility through a sequestration of L1 ORF1p from P-body. Thus, these results suggest a novel function or activity of HBV Pol in regulation of L1 retrotransposition.

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