Significance of hepatitis B core antigen in the liver in patients with chronic hepatitis B and its relation to hepatitis B virus DNA

Yoo, Jae Young; Kim, Hak Yang; Park, Choong Kee; Khang, Shin Kwang; Jeong, Jin Wu; Chung, Whan Kook; DiBisceglie, Adrian M.; Hoofnagle, Jay H.

doi:10.1111/j.1440-1746.1990.tb01623.x

Cited by 11 publications

(12 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Clinically, hepatic HBc in patients with minor hepatitis activity was distributed mainly in the nuclei. In contrast, in patients with chronic active liver diseases, hepatic HBc was distributed predominantly in the cytoplasm [14], [15], [16], [17], [18]. Mature cytoplasmic core particles contain relaxed circle (RC) DNA genome, which needs to be transported to nucleus for conversion into covalently closed circular DNA [7], [8].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nuclear Export and Import of Human Hepatitis B Virus Capsid Protein and Particles

et al. 2010

View full text Add to dashboard Cite

It remains unclear what determines the subcellular localization of hepatitis B virus (HBV) core protein (HBc) and particles. To address this fundamental issue, we have identified four distinct HBc localization signals in the arginine rich domain (ARD) of HBc, using immunofluorescence confocal microscopy and fractionation/Western blot analysis. ARD consists of four tight clustering arginine-rich subdomains. ARD-I and ARD-III are associated with two co-dependent nuclear localization signals (NLS), while ARD-II and ARD-IV behave like two independent nuclear export signals (NES). This conclusion is based on five independent lines of experimental evidence: i) Using an HBV replication system in hepatoma cells, we demonstrated in a double-blind manner that only the HBc of mutant ARD-II+IV, among a total of 15 ARD mutants, can predominantly localize to the nucleus. ii) These results were confirmed using a chimera reporter system by placing mutant or wild type HBc trafficking signals in the heterologous context of SV40 large T antigen (LT). iii) By a heterokaryon or homokaryon analysis, the fusion protein of SV40 LT-HBc ARD appeared to transport from nuclei of transfected donor cells to nuclei of recipient cells, suggesting the existence of an NES in HBc ARD. This putative NES is leptomycin B resistant. iv) We demonstrated by co-immunoprecipitation that HBc ARD can physically interact with a cellular factor TAP/NXF1 (Tip-associated protein/nuclear export factor-1), which is known to be important for nuclear export of mRNA and proteins. Treatment with a TAP-specific siRNA strikingly shifted cytoplasmic HBc to nucleus, and led to a near 7-fold reduction of viral replication, and a near 10-fold reduction in HBsAg secretion. v) HBc of mutant ARD-II+IV was accumulated predominantly in the nucleus in a mouse model by hydrodynamic delivery. In addition to the revised map of NLS, our results suggest that HBc could shuttle rapidly between nucleus and cytoplasm via a novel TAP-dependent NES.

show abstract

Section: Introductionmentioning

confidence: 99%

“…Furthermore, previous studies on this issue were performed in the context of HBc expression without HBV viral replication [23], [24], [25]. It is known that more predominant cytoplasmic HBc tends to be associated with more active HBV DNA replication [14], [15], [16], [17], [18].…”

Section: Introductionmentioning

confidence: 99%

Nuclear Export and Import of Human Hepatitis B Virus Capsid Protein and Particles

et al. 2010

View full text Add to dashboard Cite

show abstract

“…As these bodies form early in infection from the core protein subunits, the mechanism of nuclear entry of the hepadnavirus core protein is probably different from the intensively studied nuclear targeting of mature HBV nucleocapsids (Kann et al, 1999;Pante & Kann, 2002;Rabe et al, 2003). Additionally, in low-level-producing cells such as those present in chronically infected patients or HBVtransgenic mice, the core protein accumulates preferentially in the cell nucleus (Chu et al, 1995;Gowans et al, 1985;Larkin et al, 1999;Naoumov et al, 1990;Serinoz et al, 2003;Yoo et al, 1990), predominantly as empty capsids (Farza et al, 1988; Guidotti et al, 1994). This masks a possible specific localization of HBc subunits.…”

Section: Introductionmentioning

confidence: 99%

Assembly and export determine the intracellular distribution of hepatitis B virus core protein subunits

Weigand

Knaust

Schaller

2009

Journal of General Virology

View full text Add to dashboard Cite

Little is known about the parameters and factors that determine the intracellular distribution of the hepatitis B virus core protein (HBc). In order to study HBc in living cells, HBc was tagged with green fluorescent protein (GFP). Being assembly-incompetent, the GFP-fusion protein was distributed equally throughout the cell. Mutational inactivation of known serine-phosphorylation sites within the C-terminal region led to predominantly intranuclear localization. Phosphorylation of these targets, presumably by an SR domain protein kinase, resulted in a predominantly cytoplasmic localization, which suggests active cytoplasmic export or retention. The phosphoserine itself, and not its negative charge, appears essential for the underlying mechanism. In addition, the arginine-rich, protamine-like domain surrounding these phosphorylation sites does not function as the dominant nuclear-localization signal, as had been assumed previously, because neither deleting nor altering these sequences led to a change in intracellular HBc subunit distribution. Restoring the capability of the fusion protein to form capsids by co-assembly with assembly-competent, sterically uncompromised HBc subunits provided a second assay that gave insight into the effects resulting from capsid formation. Assembly was found to be the dominant factor in the cytoplasmic retention of the GFP-HBc fusion protein. Furthermore, the stability of these empty capsids was influenced by the cell-cycle inhibitor nocodazole. Thus, the intracellular distribution of HBc is dominated by cytoplasmic assembly, which is supported by the active nuclear export of HBc subunits, and modulated during the cell cycle by the instability of capsids. INTRODUCTIONHepatitis B virus (HBV) is an enveloped virus with a 3.2 kb genome containing four genes, which encode proteins with multiple functions. This is also exemplified by the 183 aa HBV core protein (HBc). It assembles into the nucleocapsid, interacting with the pregenomic RNA and the viral polymerase. In addition, HBc is involved in the process of reverse transcription and also in the second-strand synthesis of the DNA genome. It targets mature nucleocapsids to the endoplasmic reticulum, where it is believed to interact specifically with the envelope protein (Ganem, 1991;Seeger & Mason, 2000;Seifer & Standring, 1995;Wynne et al., 1999). X-ray analyses and cryo-electron microscopy, as well as mutational analyses, have revealed that HBc is a two-domain protein: a globular assembly domain encompassing aa 10-140, and an unstructured regulatory sequence containing a protamine-like domain (Seifer & Standring, 1995;Wynne et al., 1999), which is essential for the encapsidation of the pregenomic RNA and reverse transcription (Köck et al., 2004;Nassal, 1992) and supposedly for nuclear import (see below).Newly synthesized HBc remains in the cytoplasm of the infected cell, where it assembles into capsids as a first step in the formation of progeny virions. Accordingly, the core protein is mainly detected in the cytoplasm of hepatocytes...

show abstract

“…There have been several reports concerning the distribution of HBV-related proteins and HBV-DNA observed directly using immunohistochemistry and in situ hybridization [Burrell et al, 1984;Pontisso et al, 1985;Kiyosawa et al, 1988;Yoo et al, 1990;Chu and Liaw, 1992;Naumov et al, 1993;Wu et al, 1996;Lindh et al, 1999;Rodriguez-Inigo et al, 2003;Karpinska et al, 2004;Mariscal et al, 2004]. Some studies have shown, that HBV replicates diffusely in the hepatic lobules in the early phase of chronic liver disease.…”

Section: Introductionmentioning

confidence: 99%

Quantitative measurement of hepatitis B virus DNA in different areas of hepatic lobules in patients with chronic hepatitis B

Mishiro

Hamamoto

Furuta

et al. 2005

Journal of Medical Virology

View full text Add to dashboard Cite

Liver histology in chronic hepatitis B is marked by inflammatory infiltration involving the peripheral zones. The cause of such cellular infiltration remains unknown. The aim of the present study was to investigate the amounts of intrahepatic hepatitis B virus (HBV) DNA separately in the peripheral and central zones, using laser capture microdissection coupled with real-time quantitative polymerase chain reaction. Fourteen patients with chronic hepatitis B were included in the study. Liver biopsy samples were taken and hepatocytes were microdissected separately from peripheral and central zones. DNA was extracted from hepatocytes in each zone and evaluated the amounts of HBV-DNA. Immunohistochemical study for hepatitis B core antigen (HBcAg) was also performed. The amounts of total intrahepatic HBV-DNA in patients positive for hepatitis Be antigen (HBeAg) were greater than those in HBeAg-negative patients. There was no difference in HBV-DNA between the peripheral and central zones. Immunohistochemistry also showed that HBcAg-positive cells were distributed homogeneously in the hepatic lobules. In patients with peripherally predominant HBV-DNA, the serum alanine aminotransferase (ALT) level was lower than in patients with centrally predominant HBV-DNA. HBV-DNA was distributed homogeneously in the hepatic lobules. In patients with lower amounts of HBV-DNA in the peripheral zone, the serum ALT level tended to be higher than in other patients.

show abstract

Significance of hepatitis B core antigen in the liver in patients with chronic hepatitis B and its relation to hepatitis B virus DNA

Cited by 11 publications

References 16 publications

Nuclear Export and Import of Human Hepatitis B Virus Capsid Protein and Particles

Nuclear Export and Import of Human Hepatitis B Virus Capsid Protein and Particles

Assembly and export determine the intracellular distribution of hepatitis B virus core protein subunits

Quantitative measurement of hepatitis B virus DNA in different areas of hepatic lobules in patients with chronic hepatitis B

Contact Info

Product

Resources

About