Protein Interactions Network of Hepatitis E Virus RNA and Polymerase With Host Proteins

Abstract

Host-pathogen interactions are crucial for the successful propagation of pathogens inside the host cell. Knowledge of interactions between host proteins and viral proteins or viral RNA may provide clues for developing novel antiviral strategies. Hepatitis E virus (HEV), a water-borne pathogen that causes acute hepatitis in humans, is responsible for epidemics in developing countries. HEV pathology and molecular biology have been poorly explored due to the lack of efficient culture systems. A contemporary approach, to better understand the viral infection cycle at the molecular level, is the use of system biology tools depicting virus-host interactions. To determine the host proteins which participate in the regulation of HEV replication, we indentified liver cell proteins interacting with HEV RNA at its putative promoter region and those interacting with HEV polymerase (RdRp) protein. We employed affinity chromatography followed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) to identify the interacting host proteins. Protein-protein interaction networks (PPI) were plotted and analyzed using web-based tools. Topological analysis of the network revealed that the constructed network is potentially significant and relevant for viral replication. Gene ontology and pathway enrichment analysis revealed that HEV RNA promoter- and polymerase-interacting host proteins belong to different cellular pathways such as RNA splicing, RNA metabolism, protein processing in endoplasmic reticulum, unfolded protein response, innate immune pathways, secretory vesicle pathway, and glucose metabolism. We showed that hnRNPK and hnRNPA2B1 interact with both HEV putative promoters and HEV RdRp, which suggest that they may have crucial roles in HEV replication. We demonstrated in vitro binding of hnRNPK and hnRNPA2B1 proteins with the HEV targets in the study, assuring the authenticity of the interactions obtained through mass spectrometry. Thus, our study highlights the ability of viruses, such as HEV, to maneuver host systems to create favorable cellular environments for virus propagation. Studying the host-virus interactions can facilitate the identification of antiviral therapeutic strategies and novel targets.

Advances in Hepatitis E Virus Biology and Pathogenesis

“…The functional category of the proteins includes translation elongation, RNA binding, and RNA stem-loop binding. The highest number of proteins are involved in nucleic acid-binding activity, which further confirms the dependence of HEV on the host for viral RNA metabolism [149].…”

“…The mass spectrometry analysis of proteins interacting with the HEV RNA at its putative promoter region and the RdRp reveals a number of protein candidates, most of them localized to ribonucleoprotein granules, secretory granule lumen, and endocytic vesicle lumen [ 149 ]. The functional category of the proteins includes translation elongation, RNA binding, and RNA stem-loop binding.…”

Integrative Genomics Analysis Reveals a Novel 21q22.11 Locus Contributing to Susceptibility of COVID-19

“…HNRNPK acts as a central hub in the replication cycle of multiple viruses including HCV [25] . An interaction of HNRNPK and HNRNPA2B1 with hepatitis E virus (HEV) promoters has important roles in HEV replication [26] . Two cellular RNA binding proteins of hnRNPK and NS1-BP have important roles in regulating influenza A virus RNA splicing [27] .…”

On the Host Side of the Hepatitis E Virus Life Cycle

“…The mechanisms regulating the production of these RNA species from the negative-strand RNA are still unknown but imply cis-acting elements within the genome [69]. Regulation of transcription may also involve host factor(s), such as heterogeneous nuclear ribonucleoproteins (hnRNP) [70,71]. hnRNPs play a role in nuclear RNA metabolism and have been reported to re-localize to the cytoplasm of HEV-infected cells [71], similarly to what had been observed for infection with other RNA viruses [72][73][74][75][76], suggesting a potential role of hnRNPs in genomic and subgenomic HEV RNA transcription.…”