Hepatitis Delta Virus: A Peculiar Virus

The hepatitis delta virus (HDV) is distributed worldwide and related to the most severe form of viral hepatitis. HDV is a satellite RNA virus dependent on hepatitis B surface antigens to assemble its envelope and thus form new virions and propagate infection. HDV has a small 1.7 Kb genome making it the smallest known human virus. This deceivingly simple virus has unique biological features and many aspects of its life cycle remain elusive. The present review endeavors to gather the available information on HDV epidemiology and clinical features as well as HDV biology.

Download Full-text

Novel hepatitis D-like agents in vertebrates and invertebrates

10.1101/539924 ◽

2019 ◽

Cited By ~ 1

Author(s):

Wei-Shan Chang ◽

John H.-O. Pettersson ◽

Callum Le Lay ◽

Mang Shi ◽

Nathan Lo ◽

...

Keyword(s):

Hepatitis Delta Virus ◽

Evolutionary History ◽

Rna Virus ◽

Coiled Coil ◽

The Novel ◽

Leucine Zippers ◽

Hepatitis Delta ◽

Hepatitis D ◽

B Virus ◽

Delta Virus

Hepatitis delta virus (HDV) is the smallest known RNA virus and encodes a single protein. Until recently, HDV had only been identified in humans, where it is strongly associated with co-infection with hepatitis B virus (HBV). However, the recent discovery of HDV-like viruses in metagenomic samples from birds and snakes suggests that this virus has a far longer evolutionary history. Herein, using additional meta-transcriptomic data, we show that highly divergent HDV-like viruses are also present in fish, amphibians and invertebrates. Notably, the novel viruses identified here share HDV-like genomic features such as a small genome size of ~1.7kb in length, circular genomes, and self-complementary, unbranched rod-like structures. Coiled-coil domains, leucine zippers, conserved residues with essential biological functions and isoelectronic points similar to those in the human hepatitis delta virus antigens (HDAgs) were also identified in the putative non-human HDAgs. Notably, none of these novel HDV-like viruses were associated with hepadnavirus infection, supporting the idea that the HDV-HBV association may be specific to humans. Collectively, these data not only broaden our understanding of the diversity and host range of HDV in non-human species, but shed light on its origin and evolutionary history.

Download Full-text

N-Linked Glycosylation of Hepatitis B Surface Antigens Is Involved but Not Essential in the Assembly of Hepatitis Delta Virus

Virology ◽

10.1006/viro.1996.0282 ◽

1996 ◽

Vol 220 (1) ◽

pp. 28-36 ◽

Cited By ~ 23

Author(s):

CHUAN-JEN WANG ◽

SHIAN-YING SUNG ◽

DING-SHINN CHEN ◽

PEI-JER CHEN

Keyword(s):

Hepatitis B ◽

Hepatitis Delta Virus ◽

Surface Antigens ◽

Hepatitis Delta ◽

Hepatitis B Surface Antigens ◽

Delta Virus

Download Full-text

Constraint of Base Pairing on HDV Genome Evolution

Viruses ◽

10.3390/v13122350 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2350

Author(s):

Saki Nagata ◽

Ryoji Kiyohara ◽

Hiroyuki Toh

Keyword(s):

Hepatitis Delta Virus ◽

Evolutionary Rate ◽

Rna Virus ◽

Circular Rna ◽

Coding Region ◽

Base Pairing ◽

Nucleotide Substitutions ◽

Base Pairs ◽

Hepatitis Delta ◽

Delta Virus

The hepatitis delta virus is a single-stranded circular RNA virus, which is characterized by high self-complementarity. About 70% of the genome sequences can form base-pairs with internal nucleotides. There are many studies on the evolution of the hepatitis delta virus. However, the secondary structure has not been taken into account in these studies. In this study, we developed a method to examine the effect of base pairing as a constraint on the nucleotide substitutions during the evolution of the hepatitis delta virus. The method revealed that the base pairing can reduce the evolutionary rate in the non-coding region of the virus. In addition, it is suggested that the non-coding nucleotides without base pairing may be under some constraint, and that the intensity of the constraint is weaker than that by the base pairing but stronger than that on the synonymous site.

Download Full-text

Efficient Hepatitis Delta Virus RNA Replication in Avian Cells Requires a Permissive Factor(s) from Mammalian Cells

Journal of Virology ◽

10.1128/jvi.75.16.7489-7493.2001 ◽

2001 ◽

Vol 75 (16) ◽

pp. 7489-7493 ◽

Cited By ~ 5

Author(s):

Yu-Tsueng Liu ◽

Rob Brazas ◽

Don Ganem

Keyword(s):

Hepatitis Delta Virus ◽

Mammalian Cells ◽

Rna Virus ◽

Rna Replication ◽

Highly Pathogenic ◽

Hepatitis Delta ◽

Virus Rna ◽

B Virus ◽

Hdv Infection ◽

Delta Virus

ABSTRACT Hepatitis delta virus (HDV) is a highly pathogenic human RNA virus whose genome is structurally related to those of plant viroids. Although its spread from cell to cell requires helper functions supplied by hepatitis B virus (HBV), intracellular HDV RNA replication can proceed in the absence of HBV proteins. As HDV encodes no RNA-dependent RNA polymerase, the identity of the (presumably cellular) enzyme responsible for this reaction remains unknown. Here we show that, in contrast to mammalian cells, avian cells do not support efficient HDV RNA replication and that this defect cannot be rescued by provision of HDV gene products in trans. Contrary to earlier assertions, this defect is not due to enhanced apoptosis triggered in avian cells by HDV. Fusion of avian cells to mammalian cells rescues HDV replication in avian nuclei, indicating that the nonpermissive phenotype of avian cells is not due to the presence of dominantly acting inhibitors of replication. Rather, avian cells lack one or more essential permissive factors present in mammalian cells. These results set the stage for the identification of such factors and also explain the failure of earlier efforts to transmit HDV infection to avian hosts harboring indigenous hepadnaviruses.

Download Full-text

RNA Editing in Hepatitis Delta Virus: Unsolved Puzzles

The Scientific World JOURNAL ◽

10.1100/tsw.2004.123 ◽

2004 ◽

Vol 4 ◽

pp. 628-637 ◽

Cited By ~ 1

Author(s):

Geetha C. Jayan

Keyword(s):

Rna Editing ◽

Hepatitis Delta Virus ◽

Rna Virus ◽

Regulation Of Gene Expression ◽

Hepatitis Delta ◽

Adenosine Deaminases ◽

Different Types ◽

Important Player ◽

Transcriptional Changes ◽

Delta Virus

RNA editing, or post-transcriptional changes in the sequences of RNAs, is being increasingly recognized as an important player in the regulation of gene expression in vertebrates and invertebrates. Different types of RNA editing have been reported. This review discuss the type of RNA editing caused by cellular enzymes known as adenosine deaminases that act on RNAs (ADARs), and it's significance in the lifecycle of an RNA virus, hepatitis delta virus.

Download Full-text

Hepatitis delta virus and hepatocellular carcinoma: an update

Epidemiology and Infection ◽

10.1017/s0950268818001942 ◽

2018 ◽

Vol 146 (13) ◽

pp. 1612-1618 ◽

Cited By ~ 12

Author(s):

Raffaella Romeo ◽

Arnolfo Petruzziello ◽

Eve Isabel Pecheur ◽

Floriana Facchetti ◽

Riccardo Perbellini ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Hepatitis Delta Virus ◽

Rna Virus ◽

Treatment Options ◽

European Countries ◽

Hepatitis Delta ◽

Liver Decompensation ◽

Increased Risk ◽

Hdv Infection ◽

Delta Virus

AbstractHepatitis delta virus (HDV) is a defective RNA virus that depends on the presence of hepatitis B virus (HBV) for the creation of new virions and propagation of the infection to hepatocytes. Chronic infection with HDV is usually associated with a worsening of HBV infection, leading more frequently to cirrhosis, increased risk of liver decompensation and hepatocellular carcinoma (HCC) occurrence. In spite of a progressive declining prevalence of both acute and chronic HDV infection observed over several years, mainly due to increased global health policies and mass vaccination against HBV, several European countries have more recently observed stable HDV prevalence mainly due to migrants from non-European countries. Persistent HDV replication has been widely demonstrated as associated with cirrhosis development and, as a consequence, development of liver decompensation and occurrence of HCC. Several treatment options have been attempted with poor results in terms of HDV eradication and improvement of long-term prognosis. A global effort is deemed urgent to enhance the models already existing as well as to learn more about HDV infection and correlated tumourigenesis mechanisms.

Download Full-text