Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hepatitis B virus (HBV) particle consists of an envelope containing three related surface proteins and probably lipid and an icosahedral nucleocapsid of approximately 30 nm diameter enclosing the viral DNA genome and DNA polymerase. The capsid is formed in the cytosol of the infected cell during packaging of an RNA pregenome replication complex by multiple copies of a 21-kDa C protein. The capsid gains the ability to bud during synthesis of the viral DNA genome by reverse transcription of the pregenome in the lumen of the particle. The three envelope proteins S, M, and L shape a complex transmembrane fold at the endoplasmic reticulum, and form disulfide-linked homo- and heterodimers. The transmembrane topology of a fraction of the large envelope protein L changes post-translationally, therefore, the N terminal domain of L (preS) finally appears on both sides of the membrane. During budding at an intracellular membrane, a short linear domain in the cytosolic preS region interacts with binding sites on the capsid surface. The virions are subsequently secreted into the blood. In addition, the surface proteins can bud in the absence of capsids and form subviral lipoprotein particles of 20 nm diameter which are also secreted.
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PMID:Hepatitis B virus morphogenesis. 1720 55

To investigate the contributions of carboxyl-terminal nucleic acid binding domain of HBV core (C) protein for hepatitis B virus (HBV) replication, chimeric HBV C proteins were generated by substituting varying lengths of the carboxyl-terminus of duck hepatitis B virus (DHBV) C protein for the corresponding regions of HBV C protein. All chimeric C proteins formed core particles. A chimeric C protein with 221-262 amino acids of DHBV C protein, in place of 146-185 amino acids of the HBV C protein, supported HBV pregenomic RNA (pgRNA) encapsidation and DNA synthesis: 40% amino acid sequence identity or 45% homology in the nucleic-acid binding domain of HBV C protein was sufficient for pgRNA encapsidation and DNA synthesis, although we predominantly detected spliced DNA. A chimeric C protein with 221-241 and 251-262 amino acids of DHBV C, in place of HBV C 146-166 and 176-185 amino acids, respectively, could rescue full-length DNA synthesis. However, a reciprocal C chimera with 242-250 of DHBV C ((242)RAGSPLPRS(250)) introduced in place of 167-175 of HBV C ((167)RRRSQSPRR(175)) significantly decreased pgRNA encapsidation and DNA synthesis, and full-length DNA was not detected, demonstrating that the arginine-rich (167)RRRSQSPRR(175) domain may be critical for efficient viral replication. Five amino acids differing between viral species (underlined above) were tested for replication rescue; R169 and R175 were found to be important.
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PMID:C-terminal substitution of HBV core proteins with those from DHBV reveals that arginine-rich 167RRRSQSPRR175 domain is critical for HBV replication. 2291 45

Neutrophils, an important component of the innate immune system, release extracellular traps (NETs) to eliminate invading pathogens by trapping and killing microbes. Recent studies have shown that NETs play a multitude of additional roles in immunity and inflammatory diseases. Therefore, NETs may be involved in persistent hepatitis B virus (HBV) infection, and the objectives of the current study were to determine whether HBV influences NET release and to identify the underlying mechanisms. HBV-infected mice (C57BL/6) were used to detect the efficiency of bacterial eradication by neutrophils in vivo. Primary neutrophils and circulating blood samples were collected from 40 patients with chronic hepatitis B infection, as well as 40 healthy controls, to detect NET release using a Quant-iT Pico Green dsDNA assay, Western blotting, and live-cell imaging and to determine the levels of HBV-DNA and HBV markers. NET release was decreased in patients with chronic hepatitis B infection, and hepatitis B surface Ag, hepatitis B E Ag, and hepatitis B core Ab levels negatively correlated with NET release. We also examined the effect of HBV proteins (HBV X protein, HBV C protein, HBV E protein, and HBV S protein) on NET release in vitro. Based on flow cytometry, cytochrome c reduction assay, and Western blotting, HBV C protein and HBV E protein inhibited NET release by decreasing reactive oxygen species production and autophagy. Overall, HBV may inhibit NET release by modulating reactive oxygen species production and autophagy to escape the immune system and promote the establishment of chronic infection.
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PMID:Hepatitis B Virus Inhibits Neutrophil Extracellular Trap Release by Modulating Reactive Oxygen Species Production and Autophagy. 3056 31


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