There are cases of hepatitis involving occult hepatitis B virus(HBV)infection in which,even though the HB surface antigen(HBsAg)is negative,HBV-DNA is detected by a polymerase chain reaction(PCR).We con-ducted a seque...There are cases of hepatitis involving occult hepatitis B virus(HBV)infection in which,even though the HB surface antigen(HBsAg)is negative,HBV-DNA is detected by a polymerase chain reaction(PCR).We con-ducted a sequence analysis of the entire HBV region in a case of non-B non-C chronic hepatitis in a 46-yearold female.A diagnosis of non-B non-C chronic hepatitis was made.Although HBV markers,such as HBs antibody(anti-HBs),anti-HBc,HBeAg and anti-HBe,were negative,HBV-DNA was positive.Nested PCR was performed to amplify the precore region of HBV-DNA and all remaining regions by long nested PCR.Sequence analysis of the two obtained bands was conducted by direct sequencing.Compared with the control strains,the ATG(Methionine)start codon in the X region had mut ated to GTG(Valine).It is assumed that a mutation at the start codon in the X region may be the reason why HBV markers are negative in some cases of hepatitis that involve occult HBV infection.展开更多
At the 3' end of genomic hepatitis C virus(HCV) RNA there is a highly conserved untranslated region,the 3'X-tail,which forms part of the 3'UTR.This region plays key functions in regulation of critical proc...At the 3' end of genomic hepatitis C virus(HCV) RNA there is a highly conserved untranslated region,the 3'X-tail,which forms part of the 3'UTR.This region plays key functions in regulation of critical processes of the viral life cycle.The 3'X region is essential for viral replication and infectivity.It is also responsible for regulation of switching between translation and transcription of the viral RNA.There is some evidence indicating the contribution of the 3'X region to the translation efficiency of the viral polyprotein and to the encapsidation process.Several different secondary structure models of the 3'X region,based on computer predictions and experimental structure probing,have been proposed.It is likely that the 3'X region adopts more than one structural form in infected cells and that a specific equilibrium between the various forms regulates several aspects of the viral life cycle.The most intriguing explanations of the structural heterogeneity problem of the 3'X region came with the discovery of its involvement in long-range RNA-RNA interactions and the potential for homodimer formation.This article summarizes current knowledge on the structure and function of the 3'X region of hepatitis C genomic RNA,reviews previous opinions,presents new hypotheses and summarizes the questions that still remain unanswered.展开更多
AIM To detect hyper-conserved regions in the hepatitis B virus(HBV) X gene(HBX) 5' region that could be candidates for gene therapy.METHODS The study included 27 chronic hepatitis B treatmentnaive patients in vari...AIM To detect hyper-conserved regions in the hepatitis B virus(HBV) X gene(HBX) 5' region that could be candidates for gene therapy.METHODS The study included 27 chronic hepatitis B treatmentnaive patients in various clinical stages(from chronic infection to cirrhosis and hepatocellular carcinoma, both HBeA g-negative and HBeA g-positive), and infected with HBV genotypes A-F and H. In a serum sample from each patient with viremia > 3.5 log IU/m L, the HBX 5' end region [nucleotide(nt) 1255-1611] was PCRamplified and submitted to next-generation sequencing(NGS). We assessed genotype variants by phylogenetic analysis, and evaluated conservation of this region by calculating the information content of each nucleotide position in a multiple alignment of all unique sequences(haplotypes) obtained by NGS. Conservation at the HBx protein amino acid(aa) level was also analyzed.RESULTS NGS yielded 1333069 sequences from the 27 samples, with a median of 4578 sequences/sample(2487-9279, IQR 2817). In 14/27 patients(51.8%), phylogenetic analysis of viral nucleotide haplotypes showed a complex mixture of genotypic variants. Analysis of the information content in the haplotype multiple alignments detected 2 hyper-conserved nucleotide regions, one in the HBX upstream non-coding region(nt 1255-1286) and the other in the 5' end coding region(nt 1519-1603). This last region coded for a conserved amino acid region(aa 63-76) that partially overlaps a Kunitz-like domain.CONCLUSION Two hyper-conserved regions detected in the HBX 5' end may be of value for targeted gene therapy, regardless of the patients' clinical stage or HBV genotype.展开更多
文摘There are cases of hepatitis involving occult hepatitis B virus(HBV)infection in which,even though the HB surface antigen(HBsAg)is negative,HBV-DNA is detected by a polymerase chain reaction(PCR).We con-ducted a sequence analysis of the entire HBV region in a case of non-B non-C chronic hepatitis in a 46-yearold female.A diagnosis of non-B non-C chronic hepatitis was made.Although HBV markers,such as HBs antibody(anti-HBs),anti-HBc,HBeAg and anti-HBe,were negative,HBV-DNA was positive.Nested PCR was performed to amplify the precore region of HBV-DNA and all remaining regions by long nested PCR.Sequence analysis of the two obtained bands was conducted by direct sequencing.Compared with the control strains,the ATG(Methionine)start codon in the X region had mut ated to GTG(Valine).It is assumed that a mutation at the start codon in the X region may be the reason why HBV markers are negative in some cases of hepatitis that involve occult HBV infection.
基金Supported by the Polish Ministry of Science and Higher Education under the KNOW program and Foundation for Polish Science,No.POMOST/2013-8/5
文摘At the 3' end of genomic hepatitis C virus(HCV) RNA there is a highly conserved untranslated region,the 3'X-tail,which forms part of the 3'UTR.This region plays key functions in regulation of critical processes of the viral life cycle.The 3'X region is essential for viral replication and infectivity.It is also responsible for regulation of switching between translation and transcription of the viral RNA.There is some evidence indicating the contribution of the 3'X region to the translation efficiency of the viral polyprotein and to the encapsidation process.Several different secondary structure models of the 3'X region,based on computer predictions and experimental structure probing,have been proposed.It is likely that the 3'X region adopts more than one structural form in infected cells and that a specific equilibrium between the various forms regulates several aspects of the viral life cycle.The most intriguing explanations of the structural heterogeneity problem of the 3'X region came with the discovery of its involvement in long-range RNA-RNA interactions and the potential for homodimer formation.This article summarizes current knowledge on the structure and function of the 3'X region of hepatitis C genomic RNA,reviews previous opinions,presents new hypotheses and summarizes the questions that still remain unanswered.
基金Supported by the Instituto de Salud Carlos III,No.PI15/00856the European Regional Development Fund(ERDF),No.PI15/00856
文摘AIM To detect hyper-conserved regions in the hepatitis B virus(HBV) X gene(HBX) 5' region that could be candidates for gene therapy.METHODS The study included 27 chronic hepatitis B treatmentnaive patients in various clinical stages(from chronic infection to cirrhosis and hepatocellular carcinoma, both HBeA g-negative and HBeA g-positive), and infected with HBV genotypes A-F and H. In a serum sample from each patient with viremia > 3.5 log IU/m L, the HBX 5' end region [nucleotide(nt) 1255-1611] was PCRamplified and submitted to next-generation sequencing(NGS). We assessed genotype variants by phylogenetic analysis, and evaluated conservation of this region by calculating the information content of each nucleotide position in a multiple alignment of all unique sequences(haplotypes) obtained by NGS. Conservation at the HBx protein amino acid(aa) level was also analyzed.RESULTS NGS yielded 1333069 sequences from the 27 samples, with a median of 4578 sequences/sample(2487-9279, IQR 2817). In 14/27 patients(51.8%), phylogenetic analysis of viral nucleotide haplotypes showed a complex mixture of genotypic variants. Analysis of the information content in the haplotype multiple alignments detected 2 hyper-conserved nucleotide regions, one in the HBX upstream non-coding region(nt 1255-1286) and the other in the 5' end coding region(nt 1519-1603). This last region coded for a conserved amino acid region(aa 63-76) that partially overlaps a Kunitz-like domain.CONCLUSION Two hyper-conserved regions detected in the HBX 5' end may be of value for targeted gene therapy, regardless of the patients' clinical stage or HBV genotype.
