Properties of the satellite RNA of nepoviruses

Satellite RNA depend for their multiplication on the co-infection of a host cell by a helper virus which can itself multiply independently of the satellite. Four types of satellite RNA have been distinguished on the basis of the size of the RNA and what sort, if any, of protein they encode. One of them, the B-type, comprises relatively large RNA which are messenger RNA for non-structural proteins. Many of these satellites are typified by having...