This family consists mainly of the potato leaf roll virus readthrough protein. This is generated via a readthrough of open reading frame 3 a coat protein allowing transcription of open reading frame 5 to give an extended coat protein with a large c-terminal addition or read through domain. The readthrough protein is thought to play a role in the circulative aphid transmission of potato leaf roll virus. Also in the family is open reading frame 6 from beet western yellows virus and potato leaf roll virus both luteovirus and an unknown protein from cucurbit aphid-borne yellows virus a closterovirus.
Jiyao W et al.(2023). "The conserved domain database in 2023.",