Self-cleavage of RNA in the replication of viroids and virusoids.

Abstract

Viroids are infectious, circular RNA molecules of 246 to 375 nucleotides found in plants. Virusoids are of similar size and structure but they are dependent on, and encapsidated in, a helper virus. A rolling circle mechanism of replication is considered to account for the presence of greater-than-unit-length plus and minus RNAs of both viroids and virusoids found in infected plants. An essential feature of this mechanism is the specific processing or cleavage of high molecular weight intermediates to produce linear monomers which are then ligated to circular monomers. We have investigated the putative processing cleavage reactions using in vitro-synthesized RNA transcripts of dimeric cDNA cl..