Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To elucidate the relationship between the frequency of core mutations and precore mutation of hepatitis B virus (HBV) in Japanese HBV carriers, we investigated the nucleotide sequence of the precore/core region of HBV in 26 Japanese HBV carriers [15 who were HBe antigen-negative (HBeAg-) and 11 who were HBeAg-positive (HBeAg+)]. The number of amino acid changes (5.9 +/- 3.8) in the core region of HBV in HBeAg-carriers was significantly greater than that in the HBeAg+ carriers (1.5 +/- 1.0; P < 0.005). The precore stop codon mutation was found in 93.3% of HBeAg-negative HBV carriers, while no precore mutation was found in the HBeAg-positive HBV carriers, suggesting that the frequency of core mutations may be associated with the presence of the precore stop codon mutation. However, there was no significant difference in the frequency of amino acid changes among HBeAg-HBV carriers. The mean number of core amino acid changes of liver cirrhosis patients, chronic active hepatitis patients, chronic persistent hepatitis patients, and asymptomatic carriers were 2.7 +/- 1.5, 6.0 +/- 2.2, 4.7 +/- 1.2, and 8.4 +/- 5.3, respectively. We detected hot spots for core mutations, which showed characteristic localizations and specific substitutions: Gly-87, Leu-97, and Thr-130 were detected exclusively in patients with chronic liver disease with or without HBeAg. To address further the relationship between frequency of core mutations and the presence of the precore stop codon mutation, we investigated the precore/core nucleotide sequence serially along with seroconversion in three patients with chronic hepatitis B in whom the hepatitis either became inactive or remained active after the seroconversion. Emergence of the precore stop codon mutation and a significant increase in core amino-acid changes after seroconversion were noted in all three patients. Our results suggest a close association between the frequency of core amino acid changes and the presence of the precore stop codon mutation; some characteristic core mutations may be associated with the clinical course of chronic hepatitis B in Japanese patients.
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PMID:Association between frequency of amino acid changes in core region of hepatitis B virus (HBV) and the presence of precore mutation in Japanese HBV carriers. 934 86

Envelopment of the hepatitis B virus (HBV) nucleocapsid depends on the large envelope protein L, which is expressed as a transmembrane polypeptide at the endoplasmic reticulum membrane. Previous studies demonstrated that the cytosolic exposure of the N-terminal pre-S domain (174 amino acids) of L was required for virion formation. N-terminal truncations of L up to Arg 103 were tolerated. To map sites in the remaining C-terminal part of pre-S important for virion morphogenesis, a series of 11 L mutants with linker substitutions between Asn 98 and Pro 171 was generated. The mutants formed stable proteins and were secreted in transfected cell cultures, probably as components of subviral hepatitis B surface antigen particles. All four constructs with mutations between Asn 98 and Thr 125 were unable to complement in trans the block in virion formation of an L-negative HBV genome in cotransfected HuH7 cells. These mutants had a transdominant negative effect on virus yield in cotransfections with the wild-type HBV genome. In contrast, all seven mutants with substitutions downstream of Ser 124 were able to envelop the nucleocapsid and to secrete HBV. The sequence between Arg 103 and Ser 124 is highly conserved among different HBV isolates and also between HBV and the woodchuck hepatitis virus. Point mutations in this region introducing alanine residues at conserved positions blocked virion formation, in contrast to mutations at nonconserved residues. These results demonstrate that the pre-S sequence between Arg 103 and Ser 124 has an important function in HBV morphogenesis.
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PMID:A short linear sequence in the pre-S domain of the large hepatitis B virus envelope protein required for virion formation. 937 94

The mouse hepatitis virus (MHV) membrane (M) protein contains only O-linked oligosaccharides. We have used this protein as a model to study the structural requirements for O-glycosylation. We show that MHV M is modified by the addition of a single oligosaccharide side chain at the cluster of 4 hydroxylamino acids present at its extreme amino terminus and identified Thr at position 5 as the functional acceptor site. The hydroxylamino acid cluster, which is quite conserved among O-glycosylated coronavirus M proteins, is not in itself sufficient for O-glycosylation. Downstream amino acids are required to introduce a functional O-glycosylation site into a foreign protein. In a mutagenic analysis O-glycosylation was found to be sensitive to some particular changes but no unique sequence motif for O-glycosylation could be identified. Expression of mutant M proteins in cells revealed that substitution of any 1 residue was tolerated, conceivably due to the occurrence of multiple UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc transferases). Indeed, MHV M served as a substrate for GalNac-T1, -T2, and -T3, as was demonstrated using an in situ glycosylation assay based on the co-expression of endoplasmic reticulum-retained forms of the GalNAc transferases with endoplasmic reticulum-resident MHV M mutants. The GalNAc transferases were found to have largely overlapping, but distinct substrate specificities. The requirement for a threonine as acceptor rather than a serine residue and the requirement for a proline residue three positions downstream of the acceptor site were found to be distinctive features.
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PMID:Structural requirements for O-glycosylation of the mouse hepatitis virus membrane protein. 979 8

Among the many mutations found in the hepatitis B virus (HBV) genome, some have been associated with fulminant hepatitis, as exemplified by precore-defective mutations. The aim of this study was to determine whether such mutations also are found in Vietnamese cases of fulminant hepatitis B. The full-genome nucleotide sequence of HBV in three patients with fulminant hepatitis (F-2, F-3, and F-6) and one with acute hepatitis (A-3), who were admitted to Cho Ray Hospital, Ho Chi Minh City, Vietnam was ascertained. Additionally, two patients with fulminant hepatitis (F-1 and F-7) and three with acute hepatitis (A-1, A-2, and A-5) were examined only for the precore/core region of HBV. Remarkably, the nonsense mutation at precore codon 28 (Trp82Stop) was found in four of the five patients with fulminant hepatitis, while all the acute hepatitis patients harbored wild type (one had a mixture of wild and mutant types). The missense mutations within the core region, Ile97Leu and Pro130Ile/Thr/Ser, were also remarkable in fulminant hepatitis. Only F-2 was free from these precore/core mutations, but F-2 was unique in that it possessed a chimeric genotype: it could be classified into genotype C as a whole, but its X region was of genotype B, like the other four fulminant hepatitis isolates (F-1, F-3, F-6, and F-7). The codon 41 of the X protein was Pro in all three fulminant hepatitis cases examined for this region, while it was Ser in the wild-type isolates of genotype B. Of note as negative data, the mutations C1653T and T1753M of the enhancer II (Enh II) and A1762T and G1764A of the precore/core promoter regions, once reported to be relevant to severe or fulminant hepatitis, were not found in the present cases. The results with the Vietnamese cases of fulminant hepatitis corroborated results of previous studies with respect to the mutations Trp28Stop of precore and Ile97Leu and Pro130Ile/Thr/Ser of core, but not for the mutations within Enh II and precore/core promoter region. Whether the Ser41Pro mutation in the X region of genotype B HBV is Vietnam-specific or disease-specific deserves further investigation.
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PMID:Properties of hepatitis B virus genome recovered from Vietnamese patients with fulminant hepatitis in comparison with those of acute hepatitis. 1074 28

To better understand the role of beta-catenin mutation in hepatocellular carcinoma (HCC), we correlated the gene mutation with hepatitis virus B (HBV) and hepatitis virus C (HCV) status and the clinicopathological features in 366 patients with resected primary unifocal HCC. beta-Catenin mutations were also analyzed in 55 patients with multifocal HCC (68 tumors). Of the whole series, 57 (13.1%) of 434 tumors examined had beta-catenin mutations, 34 occurred at the serine/threonine residues of the GSK-3beta region of beta-catenin. Outside the GSK-3beta phosphorylation site, codons 32 and 34 were two mutational hot spots (17 tumors). The non-HBV-related HCC that was predominantly HCV related had a higher frequency of mutation (P: < 0.00001) and more frequent mutations at codon 45 than HBV-related HCC. HBV-related HCC had a younger mean age (P: < 0.00001), and higher male-to-female ratio (P: < 0.003) and positive familial history of HCC (P: < 0.014). Among 366 unifocal HCCs selected for clinicopathological analysis, beta-catenin mutations were associated with grade I (P: = 0.005) and stage I and II HCC (P: < 0.0001), and a better 5-year survival rate (P: = 0. 00003). These findings suggest mechanisms for beta-catenin mutations differ between HBV-related and non-HBV-related HCCs, and that beta-catenin mutation is a favorable prognostic factor related to low stage. beta-Catenin mutation was associated with nuclear expression of the protein (P: < 0.00001), but we failed to detect point or large fragment deletion mutation in 39 HCCs with nuclear beta-catenin expression, presumably wild-type protein. HCCs expressing mutant nuclear beta-catenin had a better 5-year survival rate (P: < 0.007), suggesting that mutant and wild-type nuclear beta-catenin proteins are not functionally equivalent and deserve more studies for further clarification.
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PMID:Beta-catenin mutations are associated with a subset of low-stage hepatocellular carcinoma negative for hepatitis B virus and with favorable prognosis. 1098 Jan 16

Mutations within T-cell or B-cell epitopes are suggested to have some influence on the clinical course of chronic hepatitis B virus (HBV) infection. To investigate the relationship between liver cell injury and heterogeneity of the HBV core gene, we focused on the sequence of codon 130, which is located on both T- and B-cell epitopes, and serially analyzed the proportion of mutant virus (core130Thr) to wild-type virus (core130Pro) during the exacerbation of chronic hepatitis B. Sera obtained serially from five HBV carriers who had exacerbation of hepatitis, and three asymptomatic HBV carriers (ASCs) with persistently normal serum aminotransferase (ALT) values were studied, using the restriction fragment length polymorphism (RFLP) method. Core130Pro predominated in the sera in the remission state, but core130Thr increased markedly in parallel with ALT elevation and decreased again after the ALT peak, followed by the predominance of core130Pro, in all the five patients. In one patient, the ratio of core130Thr/core130Pro (Thr/Pro) was more than 70% at the ALT peak. On the other hand, in sera from the three ASCs core130Pro always predominated, and no divergence was identified in the ratio of Thr/Pro. Our data suggest that codon 130 is one of the most important immunogenic regions in the HBV core gene and that elevation of Thr/Pro could be the result of immune selection.
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PMID:Mutation at codon 130 in hepatitis B virus (HBV) core region increases markedly during acute exacerbation of hepatitis in chronic HBV carriers. 1122 66

Five patients of cholestatic jaundice and multiple hyperaminoacidemias were uncovered during neonatal mass screening for homocystinuria. All five patients had increased plasma levels of methionine, citrulline, tyrosine, threonine, phenylalanine, lysine and arginine. Compared with those of age-matched cholestatic disease controls, idiopathic neonatal hepatitis (n=9) and biliary atresia (n=14), plasma levels of three amino acids, citrulline, methionine, and threonine, were significantly greater, respectively (P<0.01). Liver biopsies examined in four patients uniformly showed diffuse hepatic fatty liver with micro- and macrovesicular droplets without giant cell transformation. Administration of fat-soluble vitamins and formula milk containing middle-chain triglyceride resulted in normalization of amino acid profiles by 6 weeks after the treatment. All liver function tests normalized by 17 months of age.
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PMID:An undescribed subset of neonatal intrahepatic cholestasis associated with multiple hyperaminoacidemia. 1147 Jun 24

The conformational nature of the B cell epitopes on the hepadnavirus surface antigens makes its characterization difficult. Here, a new approach by DNA vaccination with plasmids expressing chimeric hepadnavirus surface antigens was explored to determine B cell epitopes on the surface antigens of woodchuck hepatitis virus (WHsAg). A series of chimeric genes consisting of complementary fragments of WHsAg and hepatitis B virus surface antigens (HBsAg) was constructed. These plasmids expressed the following: (i) middle chimeric surface antigens (MCSAgs), including pre-S2 region and small surface antigens; (ii) small chimeric surface antigens (CSAgs); (iii) a mutated WHsAg with two amino acid substitutions, the Leu 136 to Thr and Ala 140 to Asp, within the central immunogenic region. The mutated region from amino acid 135 to 143 within WHsAg mimics the second loop of the HBsAg a-determinant. MCSAgs and CSAgs were expressed in transiently transfected mammalian cells and were reactive to anti-HBsAg and anti-WHsAg, as shown by indirect immunofluorescence staining and ELISA. Vaccination with plasmids encoding MCSAgs induced strong antibody responses to the pre-S2 region. Anti-pre-S2 antibodies were directed to a linear, immunodominant region within the amino-terminal region of the pre-S2 region and were able to precipitate serum WHsAg. Vaccinations with the plasmids expressing the CSAgs led to the conclusion that an extended region aa 116-169 of WHsAg, analogous to the HBsAg a-determinant, was sufficient for the induction of anti-WHsAg antibodies. The mutated WHsAg with the second loop of the HBsAg a-determinant efficiently induced anti-WHsAg antibodies, but also a low titer of anti-HBsAg. Thus, multiple B cell epitopes of a linear and conformational nature are present on WHsAg. We presented an efficient and broadly applicable strategy for analysis of complex immunogenic determinants of natural or mutated viral antigens.
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PMID:Characterization of complex B cell epitopes on woodchuck hepatitis virus surface antigens by using plasmids encoding chimeric proteins and DNA immunization. 1200 76

During more than 104 weeks of treatment with lamivudine (3TC) in chronic woodchuck hepatitis virus (WHV) carrier woodchucks, viral recrudescence occurred. Analysis of WHV DNA polymerase from woodchuck serum samples by PCR followed by DNA sequencing demonstrated that all samples were wild type at the conserved YMDD motif in domain C. Four of the six 3TC-treated woodchucks showed a mixture of the wild-type Ala (GCT) and the mutant Thr (ACT) at the conserved amino acid residue 566 (FLLA) in domain B of the WHV polymerase region. The appearance of the A566T mutation was temporally associated with viral recrudescence. This change is analogous with the amino acid 181 (FLLA) in HBV where 3TC selects for a change from Ala to Thr in humans. In the woodchuck, the Ala to Thr change in the polymerase gene results in a mutation of the WHV surface protein (amino acid 377) from Trp (TGG) to an opal codon (TGA), which may prematurely terminates the polypeptide. Three WHV molecular infectious clones were constructed to study this mutation in greater detail in vitro: A566T, analogous to A181T in HBV; M589V, analogous to the M204V in HBV; and the double mutant A566T/M589V, analogous to A181T/M204V in HBV. These mutants exhibited drug-sensitivity and replication profiles that paralleled those reported for analogous HBV variants. In transfected Huh7 cells, WHV containing the M589V mutation conferred at least 100-fold increased resistance to 3TC, but replicated approximately 5-fold less efficiently than wild-type virus as judged by both extracellular virus production and intracellular DNA replicative forms. In contrast, A566T mutant was approximately 10-fold more resistant to 3TC, replicated intracellularly as well as wild type, but produced 10-fold lower levels of virions than wild type. These findings are consistent with the observation that the A566T mutation alters the overlapping WHV surface antigen reading frame. WHV carrying mutations in the conserved YMDD motif, while not directly selected during lamivudine therapy in WHV carrier woodchucks, are replication competent in cell culture indicating the potential for their emergence in treated animals. These results further illustrate the utility of the WHV/woodchuck model to studies of HBV-drug resistance.
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PMID:Mutations in the conserved woodchuck hepatitis virus polymerase FLLA and YMDD regions conferring resistance to lamivudine. 1207 58

Conformational diseases are caused by a structural rearrangement within a protein that results in aberrant intermolecular linkage and tissue deposition. This is typified by the polymers that form with the Z deficiency variant of alpha 1-antitrypsin (Glu-342 --> Lys). These polymers are retained within hepatocytes to form inclusions that are associated with hepatitis, cirrhosis, and hepatocellular carcinoma. We have assessed a surface hydrophobic cavity in alpha1-antitrypsin as a potential target for rational drug design in order to prevent polymer formation and the associated liver disease. The introduction of either Thr-114 --> Phe or Gly-117 --> Phe on strand 2 of beta-sheet A within this cavity significantly raised the melting temperature and retarded polymer formation. Conversely, Leu-100 --> Phe on helix D accelerated polymer formation, but this effect was abrogated by the addition of Thr-114 --> Phe. None of these mutations affected the inhibitory activity of alpha 1-antitrypsin. The importance of these observations was underscored by the finding that the Thr-114 --> Phe mutation reduced polymer formation and increased the secretion of Z alpha 1-antitrypsin from a Xenopus oocyte expression system. Moreover cysteine mutants within the hydrophobic pocket were able to bind a range of fluorophores illustrating the accessibility of the cavity to external agents. These results demonstrate the importance of this cavity as a site for drug design to ameliorate polymerization and prevent the associated conformational disease.
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PMID:Targeting a surface cavity of alpha 1-antitrypsin to prevent conformational disease. 1280 89


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