Identification and Characterization of Avihepadnaviruses Isolated from Exotic Anseriformes Maintained in Captivity

Guo, Haitao; Mason, William S.; Aldrich, Carol E.; Saputelli, Jeffry; Miller, Diane; Jilbert, Allison R.; Newbold, John E.

doi:10.1128/jvi.79.5.2729-2742.2005

Cited by 61 publications

(45 citation statements)

References 68 publications

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“…Plasmids expressing other adaptors or cellular signaling proteins used in the present study were constructed via similar approaches described previously (35). Briefly, to obtain cDNA clones of human RIG-I, MDA5, CARD domains of RIG-1 and MDA5, IPS-1, and IRF3, first-strand cDNA was made from Huh7 cell-derived total RNA with oligo(dT) [12][13][14][15][16][17][18] primer and Superscript III DNA polymerase (Invitrogen) by following the manufacturer's directions. Full-length cDNA for each of the forementioned genes with N-terminal FLAG tag was amplified by PCR (primer sequences are available upon request).…”

Section: Methodsmentioning

confidence: 99%

Activation of Pattern Recognition Receptor-Mediated Innate Immunity Inhibits the Replication of Hepatitis B Virus in Human Hepatocyte-Derived Cells

Guo

Jiang

et al. 2009

J Virol

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110

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Section: Methodsmentioning

confidence: 99%

Activation of Pattern Recognition Receptor-Mediated Innate Immunity Inhibits the Replication of Hepatitis B Virus in Human Hepatocyte-Derived Cells

Guo

Jiang

et al. 2009

J Virol

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110

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“…Duck hepatitis B virus (DHBV) is a common model for HBV (25,46). Avian hepadnaviruses have also been detected in heron (heron HBV [HHBV]) (41), Ross goose (Ross goose HBV [RGHBV]), snow goose (snow goose HBV [SGHBV]) (5), sheldgoose (12), stork (stork HBV [STHBV]) (32), and crane (crane HBV [CHBV]) (31).…”

Section: Identifying the Role Of Pre-p May Improve Our Understanding mentioning

confidence: 99%

“…5). It is not clear how many of the sequences that could not make pre-P represent viable viruses because few of these sequences have been tested for growth in vitro or in vivo (12,32,43). However, DHBV3, one of the viruses that cannot make pre-P, grows well in cultured cells and can infect ducks (26).…”

mentioning

confidence: 99%

Pre-P Is a Secreted Glycoprotein Encoded as an N-Terminal Extension of the Duck Hepatitis B Virus Polymerase Gene

Cao

Scougall

Jilbert

et al. 2009

J Virol

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The duck hepatitis B virus (DHBV) pregenomic RNA is a bicistronic mRNA encoding the core and polymerase proteins. Thirteen AUGs (C2 to C14) and 10 stop codons (S1 to S10) are located between the C1 AUG for the core protein and the P1 AUG that initiates polymerase translation. We previously found that the translation of the DHBV polymerase is initiated by ribosomal shunting. Here, we assessed the biosynthetic events after shunting. Translation of the polymerase open reading frame was found to initiate at the C13, C14, and P1 AUGs. Initiation at the C13 AUG occurred through ribosomal shunting because translation from this codon was cap dependent but was insensitive to blocking ribosomal scanning internally in the message. C13 and C14 are in frame with P1, and translation from these upstream start codons led to the production of larger isoforms of P. We named these isoforms "pre-P" by analogy to the pre-C and pre-S regions of the core and surface antigen open reading frames. Pre-P was produced in DHBV16 and AusDHBV-infected duck liver and was predicted to exist in 80% of avian hepadnavirus strains. Pre-P was not encapsidated into DHBV core particles, and the viable strain DHBV3 cannot make pre-P, so it is not essential for viral replication. Surprisingly, we found that pre-P is an N-linked glycoprotein that is secreted into the medium of cultured cells. These data indicate that DHBV produces an additional protein that has not been previously reported. Identifying the role of pre-P may improve our understanding of the biology of DHBV infection.Hepadnaviruses are small DNA-containing viruses that replicate by reverse transcription (39). Hepadnaviruses have been found in birds, rodents, and primates (22,38). Human hepatitis B virus (HBV) chronically infects over 350 million people worldwide and is a major cause of liver disease and liver cancer (23). Duck hepatitis B virus (DHBV) is a common model for HBV (25,46 The organization of the 3,021-nucleotide (nt)-long DHBV genome ( Fig. 1) is very compact. All nucleotides are within at least one of three open reading frames (ORFs), and the expression of multiple proteins from one ORF via initiation at multiple in-frame AUG codons is common. The first ORF encodes the core protein (C) and e antigen (e-Ag) (37), with the e-Ag being encoded as an N-terminal extension of the C ORF. The second ORF encodes the envelope proteins L and S, and like the organization of C and e-Ag, the L protein is an N-terminal extension of the S protein. The third ORF encodes the polymerase/reverse transcriptase protein (P). In mammalian viruses, a fourth ORF encodes the X protein, a multifunctional regulatory protein (2, 3). DHBV lacks an apparent X ORF, but a potential cryptic X-like ORF has been reported (6). In vivo experiments revealed no functional role for this protein in short-term infection (26).The products of all of the hepadnaviral ORFs possess regulatory functions in addition to their structural and enzymatic roles. The S ORF encodes the viral surface glycoproteins, but these proteins ar...

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“…(B) The Avihepadnavirus isolates to date come mostly from ducks and geese. Viruses that are not from domestic ducks but considered to be of the same species as duck HBV (DHBV) and Chi-tung County (CC)-DHBV isolates from China include isolates from the snow goose (SGHBV), Orinoco sheldgoose (OSHBV), ashy-headed sheldgoose (ASHBV), Puna teal (PTHBV), and Chiloé wigeon (CWHBV) (Guo et al 2005). DHBV is also found in wild mallards (Cova et al 1986), from which most domesticated ducks, except Muscovy, were derived.…”

Section: Discovery Of Animal Models Of Hbv Infectionmentioning

confidence: 99%

Animal Models and the Molecular Biology of Hepadnavirus Infection

Mason

2015

Cold Spring Harbor Perspectives in Medicine

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Australian antigen, the envelope protein of hepatitis B virus (HBV), was discovered in 1967 as a prevalent serum antigen in hepatitis B patients. Early electron microscopy (EM) studies showed that this antigen was present in 22-nm particles in patient sera, which were believed to be incomplete virus. Complete virus, much less abundant than the 22-nm particles, was finally visualized in 1970. HBV was soon found to infect chimpanzees, gorillas, orangutans, gibbon apes, and, more recently, tree shrews (Tupaia belangeri) and cynomolgus macaques (Macaca fascicularis). This restricted host range placed limits on the kinds of studies that might be performed to better understand the biology and molecular biology of HBV and to develop antiviral therapies to treat chronic infections. About 10 years after the discovery of HBV, this problem was bypassed with the discovery of viruses related to HBV in woodchucks, ground squirrels, and ducks. Although unlikely animal models, their use revealed the key steps in hepadnavirus replication and in the host response to infection, including the fact that the viral nuclear episome is the ultimate target for immune clearance of transient infections and antiviral therapy of chronic infections. Studies with these and other animal models have also suggested interesting clues into the link between chronic HBV infection and hepatocellular carcinoma.

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Identification and Characterization of Avihepadnaviruses Isolated from Exotic Anseriformes Maintained in Captivity

Cited by 61 publications

References 68 publications

Activation of Pattern Recognition Receptor-Mediated Innate Immunity Inhibits the Replication of Hepatitis B Virus in Human Hepatocyte-Derived Cells

Activation of Pattern Recognition Receptor-Mediated Innate Immunity Inhibits the Replication of Hepatitis B Virus in Human Hepatocyte-Derived Cells

Pre-P Is a Secreted Glycoprotein Encoded as an N-Terminal Extension of the Duck Hepatitis B Virus Polymerase Gene

Animal Models and the Molecular Biology of Hepadnavirus Infection

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