Protease-sensitive Structure Needed for Infectivity of Nepovirus RNA

Abstract

The infectivity of RNA obtained from particles of tobacco ringspot and tomato black ring viruses by treatment with phenol was inactivated on incubation with proteinase K or Pronase, whereas the infectivity of tobacco rattle virus RNA was not affected. The size distribution of molecules of tobacco ringspot virus RNA, assessed by polyacrylamide gel electrophoresis, was not altered by the protease treatments. Infectivity was abolished by treating either RNA-1 or RNA-2 of tomato black ring virus with proteinase K, indicating that a protease-sensitive structure needed for infectivity is attached to each RNA species. The properties of this structure are compared to those of the proteins that are covalently bonded to the genome nucleic acids of some vertebrate and bacterial viruses.