Nucleotide sequence and newly formed phosphodiester bond of spontaneously ligated satellite tobacco ringspot virus RNA.

The satellite RNA of tobacco ringspot virus (STobRV RNA) replicates and becomes encapsidated in association with tobacco ringspot virus. Previous results show that the infected tissue produces multimeric STobRV RNAs of both polarities. RNA that is complementary to encapsidated STobRV RNA, designated as having the (-) polarity, cleaves autolytically at a specific ApG bond. Purified autolysis products spontaneously join in a non-enzymic reaction. We report characteristics of this RNA ligation reaction: the terminal groups that react, the type of bond in the newly formed junction and the nucleotide sequence of the joined RNA. The nucleotide sequence of the ligated RNA shows that joining of the reacting RNAs restored an ApG bond. The junction ApG has a 3'-to-5' phosphodiester bond. Thus the net ligation reaction of STobRV (-)RNA is the precise reversal of autolysis. We discuss this new type of RNA ligation reaction and its implications for the formation of multimeric STobRV RNAs during replication.