A New Avian Hepadnavirus Infecting Snow Geese (Anser caerulescens) Produces a Significant Fraction of Virions Containing Single-Stranded DNA

Chang, Shau-Feng; Netter, Hans; Bruns, Michael; Schneider, Ralf; Frölich, Kai; Will, Hans

doi:10.1006/viro.1999.9844

Cited by 75 publications

(51 citation statements)

References 45 publications

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“…The DNA peak of PBStreated virus was concentrated in fractions 10 and 11 at a density of 1.17 g/cm 3 ( Fig. 2a, top), formerly shown to be typical for intact virions (11). When the same gradient was analyzed with an anti-DHBs antiserum by Western blotting, S and L could be detected in the same fractions, as expected (Fig.…”

Section: Ct-treated Svps Inhibit Infection Of Ct-treated Dhbvsupporting

confidence: 73%

Entry of Duck Hepatitis B Virus into Primary Duck Liver and Kidney Cells after Discovery of a Fusogenic Region within the Large Surface Protein

Maenz

Chang

Iwanski

et al. 2007

J Virol

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Hepatitis B viruses exhibit a narrow host range specificity that is believed to be mediated by a domain of the large surface protein, designated L. For duck hepatitis B virus, it has been shown that the pre-S domain of L binds to carboxypeptidase D, a cellular receptor present in many species on a wide variety of cell types. Nonetheless, only hepatocytes become infected. It has remained vague which viral features determine host range specificity and organotropicity. By using chymotrypsin to treat duck hepatitis B virus, we addressed the question of whether a putative fusogenic region within the amino-terminal end of the small surface protein may participate in viral entry and possibly constitute one of the determinants of the host range of the virus. Addition of the enzyme to virions resulted in increased infectivity. Remarkably, even remnants of enzyme-treated subviral particles proved to be inhibitory to infection. A noninfectious deletion mutant devoid of the binding region for carboxypeptidase D could be rendered infectious for primary duck hepatocytes by treatment with chymotrypsin. Although because of the protease treatment mutant and wild-type viruses may have become infectious in an unspecific and receptor-independent manner, their host range specificity was not affected, as shown by the inability of the virus to replicate in different hepatoma cell lines, as well as primary chicken hepatocytes. Instead, the organotropicity of the virus could be reduced, which was demonstrated by infection of primary duck kidney cells.The family Hepadnaviridae, with the human hepatitis B virus (HBV) as the prototype member, consists of small, DNAcontaining, enveloped viruses which cause liver diseases in humans, rodents, and birds (22). A characteristic feature of HBV and other hepadnaviruses is a strong species specificity where, e.g., HBV infects humans and chimpanzees (1) and duck HBV (DHBV) infects only certain duck and goose species (49). Moreover, all of the hepadnaviruses show relatively strict organotropicity, infecting mainly hepatocytes.Facilitated by the identification of neutralizing epitopes (12) and the allocation of host range-specific determinants to the pre-S region of L (29), it was possible to demonstrate the binding of DHBV to a putative hepatocellular receptor molecule via a certain domain on pre-S (7,8,30,39,63). This receptor molecule has been identified as gp180, a transmembrane protein of the carboxypeptidase D family that, however, has also been found in nonliver duck tissues that are not susceptible to DHBV infection (16,38,62). Furthermore, it has been shown that LMH cells, a chicken hepatoma cell line which resists infection but is capable of virus production after transfection of full-length DHBV DNA, also express gp180 (38). In addition, it was demonstrated that this molecule is concentrated in the Golgi apparatus, to cycle to and from the plasma membrane, where it colocalizes with pre-S (6, 7). Expression of duck gp180 in HuH7 cells, a human hepatoma cell line, led merely to internalizatio...

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Section: Ct-treated Svps Inhibit Infection Of Ct-treated Dhbvsupporting

confidence: 73%

Entry of Duck Hepatitis B Virus into Primary Duck Liver and Kidney Cells after Discovery of a Fusogenic Region within the Large Surface Protein

Maenz

Chang

Iwanski

et al. 2007

J Virol

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“…Naturally occurring DHBV infections have been reported in Pekin ducks and related species from China, USA, Canada, Europe, India, and South Africa [9][10][11] . Since then, avihepadnaviruses have been detected in various duck species [10] including exotic ducks and geese [10] (DHBV), in snow geese [12] (SGHBV), a Ross' goose (RGHBV, GenBank Acc.No. M95589), white storks [13] (STHBV), demoiselle and grey crowned cranes [14] (CHBV) as well as grey herons [15] (HHBV).…”

Section: Avian Hepatitis B Virusesmentioning

confidence: 99%

Avian hepatitis B viruses: Molecular and cellular biology, phylogenesis, and host tropism

Funk

Mhamdi²,

Will³

et al. 2007

WJG

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The human hepatitis B virus (HBV) and the duck hepatitis B virus (DHBV) share several fundamental features. Both viruses have a partially double-stranded DNA genome that is replicated via a RNA intermediate and the coding open reading frames (ORFs) overlap extensively. In addition, the genomic and structural organization, as well as replication and biological characteristics, are very similar in both viruses. Most of the key features of hepadnaviral infection were first discovered in the DHBV model system and subsequently confirmed for HBV. There are, however, several differences between human HBV and DHBV. This review will focus on the molecular and cellular biology, evolution, and host adaptation of the avian hepatitis B viruses with particular emphasis on DHBV as a model system.

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“…Although an immature secretion-like phenotype has also been found to occur in vivo in woodchuck and snow goose hepadnaviruses (4,26), it is puzzling that it has not been found so far in natural infection in humans (F. M. Suk, M. H. Lin, and C. Shih, unpublished results). Furthermore, it remains unclear whether an immature secretion phenotype can still be observed in the genetic context of naturally occurring variants, which often contain multiple mutations throughout the genome.…”

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confidence: 96%

Coexistence of Two Distinct Secretion Mutations (P5T and I97L) in Hepatitis B Virus Core Produces a Wild-Type Pattern of Secretion

Chua

Wen

Shih

2003

J Virol

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Unlike a Tokyo isolate of hepatitis B virus variants, we found a Shanghai isolate that secretes few virions with an immature genome despite its core I97L mutation. Core mutations P5T and I97L were found to be mutually compensatory in offsetting their respective distinct effects on virion secretion.Hepatitis B virus (HBV) replicates by using reverse transcriptase (11,24). Due to the low fidelity of the polymerase, error-prone replication and natural selection in vivo lead to the accumulation of multiple mutations in HBV variants predominant in chronic carriers (20,22). The most frequent natural mutation in the HBV core protein occurs at amino acid 97 (5, 6, 9, 10, 13). It remains a challenge to elucidate the functional significance of these prevalent and predominant mutations, since there is no a priori knowledge about what kind of assays should be used. Recently, a so-called "immature secretion" phenotype was demonstrated to be a global phenotype in tissue culture by introducing a 97L mutation into the core gene of a wild-type HBV genetic background of subtype adr and ayw origins (31,33). This phenotype of HBV variant 97L is interesting, because it represents an exception to the dogma of preferential export of virions containing mature genomes (highermolecular-weight viral DNA in relaxed circle form) in wild-type hepadnaviruses (24). Unlike the wild-type HBV, the 97L mutant secretes similar amounts of mature and immature genomes (lower-molecular-weight viral DNA in single-strand form). This phenotype is not caused by any deficiency in reverse transcription (33) or any instability of core proteins and particles (31, 33; M. Newman, F. M. Suk, and C. Shih, unpublished results).Although an immature secretion-like phenotype has also been found to occur in vivo in woodchuck and snow goose hepadnaviruses (4, 26), it is puzzling that it has not been found so far in natural infection in humans (F. M. Suk, M. H. Lin, and C. Shih, unpublished results). Furthermore, it remains unclear whether an immature secretion phenotype can still be observed in the genetic context of naturally occurring variants, which often contain multiple mutations throughout the genome. To address these issues, we took a reciprocal approach by reverting the natural mutation at amino acid 97 in a naturally occurring HBV variant from leucine back to isoleucine (L97I) and asked whether the predicted immature secretion phenotype can be abolished by eliminating the leucine residue at position 97 of the HBV core antigen (HBcAg).This parental HBV variant clone of adr subtype origin was isolated from a hepatocellular carcinoma patient from Shanghai, China (clone 14 in references 18 and 19). In addition to the hot spot mutation I97L, it contains multiple frequent mutations, including core mutations P5T and S87G, enhancer II mutations at nucleotides 1762 and 1764, and mutations truncating the X protein and abrogating the production of the pre-S2-containing M envelope protein (18). The 3.2-kb monomeric HBV genome in clone 14 was released from the pUC18 vector ...

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A New Avian Hepadnavirus Infecting Snow Geese (Anser caerulescens) Produces a Significant Fraction of Virions Containing Single-Stranded DNA

Cited by 75 publications

References 45 publications

Entry of Duck Hepatitis B Virus into Primary Duck Liver and Kidney Cells after Discovery of a Fusogenic Region within the Large Surface Protein

Entry of Duck Hepatitis B Virus into Primary Duck Liver and Kidney Cells after Discovery of a Fusogenic Region within the Large Surface Protein

Avian hepatitis B viruses: Molecular and cellular biology, phylogenesis, and host tropism

Coexistence of Two Distinct Secretion Mutations (P5T and I97L) in Hepatitis B Virus Core Produces a Wild-Type Pattern of Secretion

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