Biochemical and functional characterization of orf virus decapping protein OV71

OV71 is a decapping enzyme that hydrolyzes the cap structure on long capped mRNAs. It binds both single- and double-stranded RNA, suggesting that it may target both RNA species in infected cells. Its decapping activity is critical for efficient orf virus replication. Loss of this activity leads to the accumulation of host-capped mRNAs, a drastic reduction of viral mRNAs, and minimal impact on host rRNAs, indicating a role distinct from that of the vaccinia virus decapping enzymes.