Endogenous Hepatitis C Virus Homolog Fragments in European Rabbit and Hare Genomes Replicate in Cell Culture

Eliane Silva,Sara Marques,Júlio Carvalheira,Hugo Osório,Gertrude Thompson

doi:10.1371/journal.pone.0049820

Abstract

Endogenous retroviruses, non-retroviral RNA viruses and DNA viruses have been found in the mammalian genomes. The origin of Hepatitis C virus (HCV), the major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma in humans, remains unclear since its discovery. Here we show that fragments homologous to HCV structural and non-structural (NS) proteins present in the European rabbit (Oryctolagus cuniculus) and hare (Lepus europaeus) genomes replicate in bovine cell cultures. The HCV genomic homolog fragments were demonstrated by RT-PCR, PCR, mass spectrometry, and replication in bovine cell cultures by immunofluorescence assay (IFA) and immunogold electron microscopy (IEM) using specific MAbs for HCV NS3, NS4A, and NS5 proteins. These findings may lead to novel research approaches on the HCV origin, genesis, evolution and diversity.

Highlights

Viruses may represent genetic elements that gained the ability to move between cells, or represent previously free-living organisms that became parasites, or they may be the precursors of life [1]
Human Retrovirus 5 and endogenous lentivirus were found to be present in European rabbits [5,6], and endogenous bornaviruses, filoviruses and parvoviruses have been described in mammalian genomes [7,8]
RT-PCR, PCR and Sequencing of Rabbit and Hare To investigate if Hepatitis C virus (HCV) genomic fragments are present in the European rabbit and Lepus europaeus genomes we performed RTPCR and PCR using extracted RNA and DNA respectively from liver homogenates and sequenced all amplified products obtained with these methods

Summary

Introduction

Viruses may represent genetic elements that gained the ability to move between cells, or represent previously free-living organisms that became parasites, or they may be the precursors of life [1]. The only group of viruses known to have left a fossil record in the form of endogenous provirus’s are the retroviruses. There are studies describing that 8% of the human genome is made up of these elements [2,3]. Like non-retroviral RNA viruses, are known to generate DNA forms of their own genomes during replication [4]. A handful of endogenous retroviruses, non-retroviral RNA viruses and DNA viruses have been found in mammalian genomes. Human Retrovirus 5 and endogenous lentivirus were found to be present in European rabbits [5,6], and endogenous bornaviruses, filoviruses and parvoviruses have been described in mammalian genomes [7,8]. Calicivirus associated with hemorrhagic diseases in European rabbits and hares (Lepus europaeus and Lepus timidus) have been described [9]

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