scholarly journals Classification, structure and molecular diagnostics of avian hepatitis E virus

2019 ◽  
Vol 75 (02) ◽  
pp. 6228-2019
Author(s):  
JOANNA NERC ◽  
PIOTR SZELESZCZUK
Keyword(s):  
Hepatitis E Virus ◽  
Rna Virus ◽  
Genetic Material ◽  
Hepatitis E ◽  
Open Reading Frames ◽  
Aetiological Factor ◽  
Base Pairs ◽  
Avian Hepatitis E Virus ◽  
And Function ◽  
Overlapping Open Reading Frames

Pathological syndromes caused by avian hepatitis E virus have been described as big liver and spleen disease; necrotic haemorrhagic hepatitis-splenomegaly syndrome; necrotic, haemorrhagic, hepatomegalic hepatitis; or hepatitis-liver haemorrhage syndrome. The aetiological factor of this syndrome belongs to the Hepeviridae family. Avian hepatitis E virus is a single-strand RNA virus whose genome consists of approx. 7,200 base pairs and contains a short non-coding 5’ terminus (27-35 nucleotides) followed by three partially overlapping open reading frames: ORF1, ORF3 and ORF2. Since the avian strains of hepatitis viruses do not replicate in cell cultures, molecular biology techniques are used in the diagnosis of infections. This article discusses in detail the structure and function of each ORF of avian hepatitis E virus, as well as methods for the identification of the genetic material of this pathogen.

Hepatitis E virus

2011 ◽  
Author(s):  
X. J. Meng
Keyword(s):  
Hepatitis E Virus ◽  
Animal Species ◽  
Rna Virus ◽  
Hepatitis E ◽  
Open Reading Frames ◽  
Industrialized Countries ◽  
Efficient Cell Culture System ◽  
The Family ◽  
Avian Hev ◽  
Animal Strains

Hepatitis E virus (HEV) is a small, non-enveloped, single-strand, positive-sense RNA virus of approximately 7.2 kb in size. HEV is classified in the family Hepeviridae consisting of four recognized major genotypes that infect humans and other animals. Genotypes 1 and 2 HEV are restricted to humans and often associated with large outbreaks and epidemics in developing countries with poor sanitation conditions, whereas genotypes 3 and 4 HEV infect humans, pigs and other animal species and are responsible for sporadic cases of hepatitis E in both developing and industrialized countries. The avian HEV associated with Hepatitis-Splenomegaly syndrome in chickens is genetically and antigenically related to mammalian HEV, and likely represents a new genus in the family. There exist three open reading frames in HEV genome: ORF1 encodes non-structural proteins, ORF2 encodes the capsid protein, and the ORF3 encodes a small phosphoprotein. ORF2 and ORF3 are translated from a single bicistronic mRNA, and overlap each other but neither overlaps ORF1. Due to the lack of an efficient cell culture system and a practical animal model for HEV, the mechanisms of HEV replication and pathogenesis are poorly understood. The recent identification and characterization of animal strains of HEV from pigs and chickens and the demonstrated ability of cross-species infection by these animal strains raise potential public health concerns for zoonotic HEV transmission. It has been shown that the genotypes 3 and 4 HEV strains from pigs can infect humans, and vice versa. Accumulating evidence indicated that hepatitis E is a zoonotic disease, and swine and perhaps other animal species are reservoirs for HEV. A vaccine against HEV is not yet available.

scholarly journals Hepatitis E Virus Replication

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 719 ◽  
Author(s):  
Robert LeDesma ◽  
Ila Nimgaonkar ◽  
Alexander Ploss
Keyword(s):  
Hepatitis E Virus ◽  
Rna Virus ◽  
Hypervariable Region ◽  
Hepatitis E ◽  
Open Reading Frames ◽  
Health Concern ◽  
Viral Gene ◽  
Genome Replication ◽  
Replication Strategy ◽  
Viral Gene Product

Hepatitis E virus (HEV) is a small quasi-enveloped, (+)-sense, single-stranded RNA virus belonging to the Hepeviridae family. There are at least 20 million HEV infections annually and 60,000 HEV-related deaths worldwide. HEV can cause up to 30% mortality in pregnant women and progress to liver cirrhosis in immunocompromised individuals and is, therefore, a greatly underestimated public health concern. Although a prophylactic vaccine for HEV has been developed, it is only licensed in China, and there is currently no effective, non-teratogenic treatment. HEV encodes three open reading frames (ORFs). ORF1 is the largest viral gene product, encoding the replicative machinery of the virus including a methyltransferase, RNA helicase, and an RNA-dependent RNA polymerase. ORF1 additionally contains a number of poorly understood domains including a hypervariable region, a putative protease, and the so-called ‘X’ and ‘Y’ domains. ORF2 is the viral capsid essential for formation of infectious particles and ORF3 is a small protein essential for viral release. In this review, we focus on the domains encoded by ORF1, which collectively mediate the virus’ asymmetric genome replication strategy. We summarize what is known, unknown, and hotly debated regarding the coding and non-coding regions of HEV ORF1, and present a model of how HEV replicates its genome.

scholarly journals Characterization of the hepatitis E virus replicase

2021 ◽  
Author(s):  
Karoline Metzger ◽  
Cyrine Bentaleb ◽  
Kévin Hervouet ◽  
Virginie Alexandre ◽  
Claire Montpellier ◽  
...  
Keyword(s):  
Hepatitis E Virus ◽  
Rna Virus ◽  
Simultaneous Detection ◽  
Hypervariable Region ◽  
Hepatitis E ◽  
Full Length ◽  
Open Reading Frames ◽  
Subgenomic Rna ◽  
Genomic Rnas ◽  
Molecular Weights

AbstractHepatitis E virus (HEV) is the major cause of acute hepatitis worldwide. HEV is a positive-sense RNA virus expressing 3 open reading frames (ORFs). ORF1 encodes the ORF1 non– structural polyprotein, the viral replicase which transcribes the full-length genome and a subgenomic RNA that encodes the structural ORF2 and ORF3 proteins. The present study is focused on the replication step with the aim to determine whether the ORF1 polyprotein is processed during the HEV lifecycle and to identify where the replication takes place inside the host cell. As no commercial antibody recognizes ORF1 in HEV-replicating cells, we aimed at inserting epitope tags within the ORF1 protein without impacting the virus replication efficacy. Two insertion sites located in the hypervariable region were thus selected to tolerate the V5 epitope while preserving HEV replication efficacy. Once integrated into the infectious full-length Kernow C-1 p6 strain, the V5 epitopes did neither impact the replication of genomic nor the production of subgenomic RNA. Also, the V5-tagged viral particles remained as infectious as the wildtype particles to Huh-7.5 cells. Next, the expression pattern of the V5-tagged ORF1 was compared in heterologous expression and replicative HEV systems. A high molecular weight protein (180 kDa) that was expressed in all 3 systems and that likely corresponds to the unprocessed form of ORF1 was detected up to 25 days after electroporation in the p6 cell culture system. Additionally, less abundant products of lower molecular weights were detected in both in cytoplasmic and nuclear compartments. Concurrently, the V5-tagged ORF1 was localized by confocal microscopy inside the cell nucleus but also as compact perinuclear substructures in which ORF2 and ORF3 proteins were detected. Importantly, using in situ hybridization (RNAScope®), positive and negative-strand HEV RNAs were localized in the perinuclear substructures of HEV-producing cells. Finally, by simultaneous detection of HEV genomic RNAs and viral proteins in these substructures, we identified candidate HEV factories.

scholarly journals Progress in the Production of Virus-Like Particles for Vaccination against Hepatitis E Virus

Viruses ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 826
Author(s):  
Milena Mazalovska ◽  
J. Calvin Kouokam
Keyword(s):  
Viral Hepatitis ◽  
Hepatitis E Virus ◽  
Vaccine Development ◽  
Genetic Material ◽  
Hepatitis E ◽  
Open Reading Frames ◽  
Virus Like Particles ◽  
Ssrna Virus ◽  
Potential Vaccine ◽  
Reading Frames

Hepatitis E virus (HEV), a pathogen that causes acute viral hepatitis, is a small icosahedral, quasi-enveloped, positive ssRNA virus. Its genome has three open reading frames (ORFs), with ORF1 and ORF3 encoding for nonstructural and regulatory proteins, respectively, while ORF2 is translated into the structural, capsid protein. ORF2 is most widely used for vaccine development in viral hepatitis. Hepatitis E virus-like particles (VLPs) are potential vaccine candidates against HEV infection. VLPs are composed of capsid subunits mimicking the natural configuration of the native virus but lack the genetic material needed for replication. As a result, VLPs are unable to replicate and cause disease, constituting safe vaccine platforms. Currently, the recombinant VLP-based vaccine Hecolin® against HEV is only licensed in China. Herein, systematic information about the expression of various HEV ORF2 sequences and their ability to form VLPs in different systems is provided.

scholarly journals Determination and analysis of the complete genomic sequence of avian hepatitis E virus (avian HEV) and attempts to infect rhesus monkeys with avian HEV

2004 ◽  
Vol 85 (6) ◽  
pp. 1609-1618 ◽  
Author(s):  
F. F. Huang ◽  
Z. F. Sun ◽  
S. U. Emerson ◽  
R. H. Purcell ◽  
H. L. Shivaprasad ◽  
...  
Keyword(s):  
Rhesus Monkeys ◽  
Hepatitis E Virus ◽  
Genomic Sequence ◽  
Hepatitis E ◽  
The United States ◽  
Open Reading Frames ◽  
Coding Region ◽  
Virus Shedding ◽  
Avian Hepatitis E Virus ◽  
Avian Hev

Avian hepatitis E virus (avian HEV), recently identified from a chicken with hepatitis–splenomegaly syndrome in the United States, is genetically and antigenically related to human and swine HEVs. In this study, sequencing of the genome was completed and an attempt was made to infect rhesus monkeys with avian HEV. The full-length genome of avian HEV, excluding the poly(A) tail, is 6654 bp in length, which is about 600 bp shorter than that of human and swine HEVs. Similar to human and swine HEV genomes, the avian HEV genome consists of a short 5′ non-coding region (NCR) followed by three partially overlapping open reading frames (ORFs) and a 3′NCR. Avian HEV shares about 50 % nucleotide sequence identity over the complete genome, 48–51 % identity in ORF1, 46–48 % identity in ORF2 and only 29–34 % identity in ORF3 with human and swine HEV strains. Significant genetic variations such as deletions and insertions, particularly in ORF1 of avian HEV, were observed. However, motifs in the putative functional domains of ORF1, such as the helicase and methyltransferase, were relatively conserved between avian HEV and mammalian HEVs, supporting the conclusion that avian HEV is a member of the genus Hepevirus. Phylogenetic analysis revealed that avian HEV represents a branch distinct from human and swine HEVs. Swine HEV infects non-human primates and possibly humans and thus may be zoonotic. An attempt was made to determine whether avian HEV also infects across species by experimentally inoculating two rhesus monkeys with avian HEV. Evidence of virus infection was not observed in the inoculated monkeys as there was no seroconversion, viraemia, faecal virus shedding or serum liver enzyme elevation. The results from this study confirmed that avian HEV is related to, but distinct from, human and swine HEVs; however, unlike swine HEV, avian HEV is probably not transmissible to non-human primates.

Infection of Pigs with Avian Hepatitis E Virus (HEV)

2005 ◽  
Author(s):  
C. Kasorndorkbua ◽  
P. J. Thomas ◽  
Patrick G. Halbur ◽  
D. K. Guenette ◽  
F. F. Huang ◽  
...  
Keyword(s):  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Avian Hepatitis E Virus

Identification and characterization of avian hepatitis E virus genotype 2 from chickens with hepatitis-splenomegaly syndrome in Korea

Virus Genes ◽  
2016 ◽  
Vol 52 (5) ◽  
pp. 738-742 ◽  
Author(s):  
Hyun-Woo Moon ◽  
Byung-Woo Lee ◽  
Haan Woo Sung ◽  
Byung-Il Yoon ◽  
Hyuk Moo Kwon
Keyword(s):  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Virus Genotype ◽  
Genotype 2 ◽  
Avian Hepatitis E Virus ◽  
Identification And Characterization

scholarly journals Identification of two neutralization epitopes on the capsid protein of avian hepatitis E virus

2008 ◽  
Vol 89 (2) ◽  
pp. 500-508 ◽  
Author(s):  
E.-M. Zhou ◽  
H. Guo ◽  
F. F. Huang ◽  
Z. F. Sun ◽  
X. J. Meng
Keyword(s):  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Avian Hepatitis E Virus

Molecular characterization of a novel mycovirus isolated from Rhizoctonia solani AG-1 IA 9-11

2021 ◽  
Author(s):  
Yang Sun ◽  
Yan qiong Li ◽  
Wen han Dong ◽  
Ai li Sun ◽  
Ning wei Chen ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Rna Virus ◽  
Dsrna Virus ◽  
Open Reading Frames ◽  
The Family ◽  
Significant Amino Acid Sequence ◽  
Overlapping Open Reading Frames ◽  
Significant Amino Acid ◽  
Reading Frames

Abstract The complete genome of the dsRNA virus isolated from Rhizoctonia solani AG-1 IA 9–11 (designated as Rhizoctonia solani dsRNA virus 11, RsRV11 ) were determined. The RsRV11 genome was 9,555 bp in length, contained three conserved domains, SMC, PRK and RT-like super family, and encoded two non-overlapping open reading frames (ORFs). ORF1 potentially coded for a 204.12 kDa predicted protein, which shared low but significant amino acid sequence identities with the putative protein encoded by Rhizoctonia solani RNA virus HN008 (RsRV-HN008) ORF1. ORF2 potentially coded for a 132.41 kDa protein which contained the conserved motifs of the RNA-dependent RNA polymerase (RdRp). Phylogenetic analysis indicated that RsRV11 was clustered with RsRV-HN008 in a separate clade independent of other virus families. It implies that RsRV11, along with RsRV-HN008 possibly a new fungal virus taxa closed to the family Megabirnaviridae, and RsRV11 is a new member of mycoviruses.

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