Are in vitro hepatitis B core promoter mutations important for clinical alterations in viral load?☆

Cheng, Yan; Seet, Bee Leng; Ong, Corinne; Wasser, Shanthi; Tan, Thiam Soon; Peter, Frank; Lim, Seng Gee

doi:10.1016/j.antiviral.2005.11.005

Cited by 7 publications

(5 citation statements)

References 52 publications

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“…Moreover, the consensus binding sequences of RFX1 share extremely high homology with the sequence of NREγ subregion, from nt. 1605 to 1617 [26], [32], [33], [34] (Figure 6A). Intriguingly, the G1613A mutation on the NREγ site further matches the consensus RFX1 binding sequence, which is consistent to our result that the C2 complex showed higher affinity to mutant than wild-type DNA.…”

Section: Resultsmentioning

confidence: 99%

The G1613A Mutation in the HBV Genome Affects HBeAg Expression and Viral Replication through Altered Core Promoter Activity

Lau

Chan

et al. 2011

PLoS ONE

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Infection of hepatitis B virus (HBV) causes acute and chronic hepatitis and is closely associated with the development of cirrhosis and hepatocellular carcinoma (HCC). Previously, we demonstrated that the G1613A mutation in the HBV negative regulatory element (NRE) is a hotspot mutation in HCC patients. In this study, we further investigated the functional consequences of this mutation in the context of the full length HBV genome and its replication. We showed that the G1613A mutation significantly suppresses the secretion of e antigen (HBeAg) and enhances the synthesis of viral DNA, which is in consistence to our clinical result that the G1613A mutation associates with high viral load in chronic HBV carriers. To further investigate the molecular mechanism of the mutation, we performed the electrophoretic mobility shift assay with the recombinant RFX1 protein, a trans-activator that was shown to interact with the NRE of HBV. Intriguingly, RFX1 binds to the G1613A mutant with higher affinity than the wild-type sequence, indicating that the mutation possesses the trans-activating effect to the core promoter via NRE. The trans-activating effect was further validated by the enhancement of the core promoter activity after overexpression of RFX1 in liver cell line. In summary, our results suggest the functional consequences of the hotspot G1613A mutation found in HBV. We also provide a possible molecular mechanism of this hotspot mutation to the increased viral load of HBV carriers, which increases the risk to HCC.

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Section: Resultsmentioning

confidence: 99%

The G1613A Mutation in the HBV Genome Affects HBeAg Expression and Viral Replication through Altered Core Promoter Activity

Lau

Chan

et al. 2011

PLoS ONE

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“…Most of these studies are based on transfecting HBV DNA into cells in culture but virus replication in vitro differs from that in vivo , where it is influenced by the interaction of virus with the complex host immune system. The effect of BCP double mutations on virus replication in vitro may not be representative of the situation in vivo [25]. Although other studies are based on clinical samples, they all involve cross-sectional analysis and viral loads may fluctuate over time [19].…”

Section: Discussionmentioning

confidence: 99%

The association of HBV core promoter double mutations (A1762T and G1764A) with viral load differs between HBeAg positive and anti-HBe positive individuals: A longitudinal analysis

Fang

Sabin

Dong

et al. 2009

Journal of Hepatology

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Background/AimsAlthough there have been a few reports regarding the effect of basal core promoter (BCP) double mutations (A1762T and G1764A) on hepatitis B viral loads, the association remains uncertain. We aim to determine the association after controlling for HBeAg – a strong confounding factor.MethodsWe selected randomly 190 individuals from a Chinese cohort of 2258 subjects for cross-sectional analysis and 56 of the 190 for longitudinal analysis of viral loads.ResultsIn multivariable analysis of the cross-sectional data, BCP double mutations are significantly associated with lower viral loads in HBeAg positive subjects but no difference was found in anti-HBe positive subjects. Triple mutations at nucleotide (nt) 1753, 1762 and 1764 and mutations between nt 1809 and 1817, precore stop mutation (nt 1896) and genotype are not associated with viral loads in either HBeAg or anti-HBe positive subjects. Analysis of the longitudinal data yielded similar results to the cross-sectional data. Viral loads differ significantly between individuals infected with wild-type and BCP double mutations prior to HBeAg seroconversion but this difference is lost after seroconversion.ConclusionsBCP double mutations are associated with lower viral loads in HBeAg positive individuals but have no effect on the viral loads of anti-HBe positive individuals.

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“…Pregenomic RNA also serves as a reverse transcription template after encapsidation. A variety of liver-enriched and ubiquitous transcription factors target the promoter and enhancer regions to regulate viral transcription and replication (as reviewed in 4 , 5 ). In addition, several forms of spliced RNAs are generated from 3.5 kb RNA.…”

Section: Introductionmentioning

confidence: 99%

Involvement of PUF60 in Transcriptional and Post-transcriptional Regulation of Hepatitis B Virus Pregenomic RNA Expression

Sun

Nakashima

Ito

et al. 2017

Sci Rep

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Here we identified PUF60, a splicing factor and a U2 small nuclear ribonucleoprotein auxiliary factor, as a versatile regulator of transcriptional and post-transcriptional steps in expression of hepatitis B virus (HBV) 3.5 kb, precore plus pregenomic RNA. We demonstrate that PUF60 is involved in: 1) up-regulation of core promoter activity through its interaction with transcription factor TCF7L2, 2) promotion of 3.5 kb RNA degradation and 3) suppression of 3.5 kb RNA splicing. When the 1.24-fold HBV genome was introduced into cells with the PUF60-expression plasmid, the 3.5 kb RNA level was higher at days 1–2 post-transfection but declined thereafter in PUF60-expressing cells compared to viral replication control cells. Deletion analyses showed that the second and first RNA recognition motifs (RRMs) within PUF60 are responsible for core promoter activation and RNA degradation, respectively. Expression of PUF60 mutant deleting the first RRM led to higher HBV production. To our knowledge, this is the first to identify a host factor involved in not only positively regulating viral gene expression but also negative regulation of the same viral life cycle. Functional linkage between transcriptional and post-transcriptional controls during viral replication might be involved in mechanisms for intracellular antiviral defense and viral persistence.

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Are in vitro hepatitis B core promoter mutations important for clinical alterations in viral load?☆

Cited by 7 publications

References 52 publications

The G1613A Mutation in the HBV Genome Affects HBeAg Expression and Viral Replication through Altered Core Promoter Activity

The G1613A Mutation in the HBV Genome Affects HBeAg Expression and Viral Replication through Altered Core Promoter Activity

The association of HBV core promoter double mutations (A1762T and G1764A) with viral load differs between HBeAg positive and anti-HBe positive individuals: A longitudinal analysis

Involvement of PUF60 in Transcriptional and Post-transcriptional Regulation of Hepatitis B Virus Pregenomic RNA Expression

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