The ORF3 Protein of Hepatitis E Virus Interacts with Liver-specific α1-Microglobulin and Its Precursor α1-Microglobulin/Bikunin Precursor (AMBP) and Expedites Their Export from the Hepatocyte

Hepatitis E virus (HEV) strains are classified into 4 genotypes by nucleotide sequencing. Genotypes 3 and 4 infect humans and animals via HEV-contaminated food or water. HEV RNA was detected by PCR and antibodies were detected by ELISA. Since human studies showed that HEV IgG antibodies in sera can persist for extended periods, diagnosis of HEV infection in swine or humans is mainly based on serological detection using commercial ELISA kits. However, there is no supplemental method to verify ELISA results. Hence, we developed a novel method used for mutual correction of these common processes. Here, a modified stable HepG2 cell line was transfected with pcDNA3.1-ORF3 to express the swine HEV ORF3 protein. Based on this cell line, a novel immunoperoxidase monolayer assay (IPMA) was developed to detect antibodies against HEV. The results show that this method has good specificity, sensitivity and repeatability. When used to investigate 141 porcine serum samples, the IPMA had a coincidence rate of 92.2% with a commercial ELISA kit. The established IPMA described herein is valuable as a supplemental method to ELISA and can differentiate infections by HEV and other viruses.

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P.427 The hepatitis E virus ORF3 protein modulates endocytic trafficking and the acute phase protein response

Journal of Clinical Virology ◽

10.1016/s1386-6532(06)80600-1 ◽

2006 ◽

Vol 36 ◽

pp. S193

Author(s):

A. Kar-Roy ◽

V. Chandra ◽

S. Kumari ◽

S. Mayor ◽

S. Jameel

Keyword(s):

Acute Phase ◽

Hepatitis E Virus ◽

Acute Phase Protein ◽

Hepatitis E ◽

Endocytic Trafficking ◽

Orf3 Protein ◽

Acute Phase Protein Response ◽

Phase Protein ◽

Protein Response

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Production of monoclonal antibodies against the ORF3 protein of rat hepatitis E virus (HEV) and demonstration of the incorporation of the ORF3 protein into enveloped rat HEV particles

Archives of Virology ◽

10.1007/s00705-016-3047-9 ◽

2016 ◽

Vol 161 (12) ◽

pp. 3391-3404 ◽

Cited By ~ 3

Author(s):

Masaharu Takahashi ◽

Tominari Kobayashi ◽

Tanggis ◽

Suljid Jirintai ◽

Mulyanto ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Hepatitis E Virus ◽

Hepatitis E ◽

Orf3 Protein

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Hepatitis E Virus ORF3 Protein Forms Membrane-Associated Oligomers

Journal of Hepatology ◽

10.1016/s0168-8278(16)00602-4 ◽

2016 ◽

Vol 64 (2) ◽

pp. S389

Author(s):

J. Gouttenoire ◽

J. Mauron ◽

J. Oppliger ◽

M. Matter ◽

V.L.D. Thi ◽

...

Keyword(s):

Hepatitis E Virus ◽

Hepatitis E ◽

Orf3 Protein

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The Endocytic Recycling Compartment Serves as a Viral Factory for Hepatitis E Virus

10.1101/2021.10.14.464345 ◽

2021 ◽

Author(s):

Cyrine Bentaleb ◽

Kévin Hervouet ◽

Claire Montpellier ◽

Charline Camuzet ◽

Julien Burlaud-Gaillard ◽

...

Keyword(s):

Capsid Protein ◽

Hepatitis E Virus ◽

Hepatitis E ◽

Cellular Membrane ◽

Tubular Structures ◽

Endocytic Recycling ◽

Orf3 Protein ◽

Positive Strand Rna ◽

Viral Factory ◽

The Impact

Background & Aims: Although Hepatitis E virus (HEV) is the major leading cause of enterically transmitted viral hepatitis worldwide, many gaps remain in the understanding of the HEV lifecycle. Notably, viral factories induced by HEV have not been documented yet and it is currently unknown whether HEV infection leads to cellular membrane modelling as many positive-strand RNA viruses. HEV genome encodes three proteins, the ORF1 replicase, the ORF2 capsid protein and the ORF3 protein involved in virion egress. Previously, we demonstrated that HEV produces different ORF2 isoforms including the virion-associated ORF2i form. Here, we aimed to probe infectious particles and viral factories in HEV-producing cells, using antibodies directed against the different ORF2 isoforms. Methods: We generated monoclonal antibodies that specifically recognize the particle-associated ORF2i form, and antibodies that recognize the different ORF2 isoforms. We used them in confocal and electron microscopy approaches to probe viral factories in HEV-producing cells. We performed an extensive colocalization study of viral proteins with subcellular markers. We analyzed the impact of silencing Rab11, a central player of the endocytic recycling compartment (ERC). Results: One of the antibodies, named P1H1 and targeting the N-terminus of ORF2i, recognized delipidated HEV particles. Confocal and ultrastructural microscopy analyses of HEV-producing cells revealed an unprecedented HEV-induced membrane network containing tubular and vesicular structures. These subcellular structures were enriched in ORF2 and ORF3 proteins, and were dependent on the ORF3 expression and ORF2i capsid protein assembly. Colocalization and silencing analyses revealed that these structures are derived from the ERC. Conclusions: Our study reveals that HEV hijacks the ERC and forms a membrane network of vesicular and tubular structures that might be the hallmark of HEV infection.

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ORF3 protein of hepatitis E virus is essential for virion release from infected cells

Journal of General Virology ◽

10.1099/vir.0.010561-0 ◽

2009 ◽

Vol 90 (8) ◽

pp. 1880-1891 ◽

Cited By ~ 146

Author(s):

Kentaro Yamada ◽

Masaharu Takahashi ◽

Yu Hoshino ◽

Hideyuki Takahashi ◽

Koji Ichiyama ◽

...

Keyword(s):

Hepatitis E Virus ◽

Culture Medium ◽

Culture Supernatant ◽

Limit Of Detection ◽

A549 Cells ◽

Hepatitis E ◽

Wild Type ◽

Orf3 Protein ◽

Virion Release ◽

Infected Cells

The function of the hepatitis E virus (HEV) open reading frame 3 (ORF3) protein remains unclear. To elucidate the role of the ORF3 protein in the virus life cycle, an infectious cDNA clone (pJE03-1760F/wt) that can replicate efficiently in PLC/PRF/5 and A549 cells and release progeny into the culture medium was used to generate a derivative ORF3-deficient (ΔORF3) mutant whose third in-frame AUG codon of ORF3 was mutated to GCA. The ΔORF3 mutant in the culture medium of mutant RNA-transfected PLC/PRF/5 cells was able to infect and replicate within PLC/PRF/5 and A549 cells as efficiently as the wild-type pJE03-1760F/wt virus. However, less than 1/100 of the number of progeny was detectable in the culture medium of ΔORF3 mutant-infected PLC/PRF/5 cells compared with wild-type-infected PLC/PRF/5 cells, and the HEV RNA level in the culture medium of ΔORF3 mutant-infected A549 cells was below or near the limit of detection. An immunocapture PCR assay revealed that the ORF3 protein is present on the surface of cell-culture-generated wild-type HEV but not on the ΔORF3 mutant. Wild-type HEV in the culture supernatant peaked at a sucrose density of 1.15–1.16 g ml−1, in contrast with the ΔORF3 mutant in culture supernatant, which banded at 1.27–1.28 g ml−1, similar to HEV in cell lysate and faecal HEV. These results suggest that the ORF3 protein is responsible for virion egress from infected cells and is present on the surface of released HEV particles, which may be associated with lipids.

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Palmitoylation mediates membrane association of hepatitis E virus ORF3 protein and is required for infectious particle secretion

PLoS Pathogens ◽

10.1371/journal.ppat.1007471 ◽

2018 ◽

Vol 14 (12) ◽

pp. e1007471 ◽

Cited By ~ 17

Author(s):

Jérôme Gouttenoire ◽

Angela Pollán ◽

Laurence Abrami ◽

Noémie Oechslin ◽

Johann Mauron ◽

...

Keyword(s):

Hepatitis E Virus ◽

Hepatitis E ◽

Membrane Association ◽

Infectious Particle ◽

Orf3 Protein

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The viral ORF3 protein is required for hepatitis E virus apical release and efficient growth in polarized hepatocytes and humanized mice

Journal of Virology ◽

10.1128/jvi.00585-21 ◽

2021 ◽

Author(s):

Gulce Sari ◽

Jingting Zhu ◽

Charuta Ambardekar ◽

Xin Yin ◽

Andre Boonstra ◽

...

Keyword(s):

Life Cycle ◽

Persistent Infection ◽

Human Liver ◽

Hepatitis E Virus ◽

Hepatitis E ◽

Productive Infection ◽

Humanized Mice ◽

Hepatocyte Culture ◽

Fecal Shedding ◽

Orf3 Protein

Hepatitis E virus (HEV), an enterically transmitted RNA virus, is a major cause of acute hepatitis worldwide. Additionally, HEV genotype (gt) 3 can frequently persist in immunocompromised individuals with an increased risk for developing severe liver disease. Currently, no HEV-specific treatment is available. The viral open reading frame 3 (ORF3) protein facilitates HEV egress in vitro and is essential for establishing productive infection in macaques. Thus, ORF3, which is unique to HEV, has the potential to be explored as a target for antiviral therapy. However, significant gaps exist in our understanding of the critical functions of ORF3 in HEV infection in vivo . Here, we utilized a polarized hepatocyte culture model and a human liver chimeric mouse model to dissect the roles of ORF3 in gt3 HEV release and persistent infection. We show that ORF3’s absence substantially decreased HEV replication and virion release from the apical surface but not the basolateral surface of polarized hepatocytes. While the wild-type HEV established a persistent infection in humanized mice, mutant HEV lacking ORF3 (ORF3null) failed to sustain the infection despite transient replication in the liver and was ultimately cleared. Strikingly, mice inoculated with the ORF3null virus displayed no fecal shedding throughout the six-week experiment. Overall, our results demonstrate that ORF3 is required for HEV fecal shedding and persistent infection, providing a rationale for targeting ORF3 as a treatment strategy for HEV infection. Importance HEV infections are associated with significant morbidity and mortality. HEV gt3 additionally can cause persistent infection which can rapidly progress to liver cirrhosis. Currently, no HEV-specific treatments are available. The poorly understood HEV life cycle hampers the development of antivirals for HEV. Here we investigated the role of the viral ORF3 protein in HEV infection in polarized hepatocyte culture and human liver chimeric mice. We found that two major aspects of the HEV life cycle require ORF3: fecal virus shedding and persistent infection. These results provide a rationale for targeting ORF3 to treat HEV infection.

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