Viral helicase and methyltransferase promote genotype one-hepatitis e virus internal ribosome entry site-like element activity

Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis. Our earlier study reported the presence of an 87-nucleotide-long internal ribosome entry-site-like element (IRESl) in the genotype 1 (g1)-HEV genome, which mediated cap-independent translation of the viral ORF4 protein. RNA-protein interactome analysis of the HEV IRESl revealed its association with multiple host proteins, including translation regulatory proteins, which controlled its function. Role of HEV-encoded proteins in modulating the viral IRESl activity remains unknown. In the present study, we investigated the role of viral proteins in modulating the activity of the HEV IRESl element. Luciferase-reporter assay using a bicistronic vector revealed the ability of viral Helicase and MeT-Y-domain proteins in upregulating the HEV IRESl activity. Further studies confirmed direct interaction of the viral Helicase and MeT-Y-domain with the HEV IRESl. Collectively, these findings unravel the positive role of HEV Helicase and MeT-Y-domain proteins in modulating the viral IRESl activity.