Genome organization of cutthroat trout virus and human hepatitis E virus. A short 5′ non-coding region is followed by ORF1, encoding non-structural proteins including the putative functional domains: MT, methytransferase; P, a putative papain-like cysteine protease; HUD, Hepeviridae unique domain, also called the Z domain [7]; PP, a hypervariable polyproline region that is dispensable for virus infectivity; Macro, macro domain; Hel, helicase; and RdRP, RNA-dependent RNA polymerase [7, 8]. ORF2 encodes a capsid protein and is followed by a short 3′ NCR. ORF3 overlaps ORF2 in a different reading frame and encodes a small phosphoprotein with a multi-functional C-terminal region. The scale is in bases.