37] Compilation of self-cleaving sequences from plant virus satellite RNAs and other sources

Abstract

This chapter presents the compilation of self-cleaving sequences from plant virus satellite RNAS and other sources. Several RNA-mediated, RNA-cleaving and -joining reactions have 5′-phosphorylated intermediates or products. Most of the self-cleaving RNA molecules have their origin in the sequences of satellite RNAs of plant viruses. A satellite RNA does not replicate when inoculated alone to a plant. A satellite RNA requires infection of the plant host by any one of a group of closely related supporting viruses. The satellite RNA becomes encapsidated in the coat protein of that virus, some as linear molecules and others predominantly as circles. The encapsidated forms of known small satellite RNAs are predominantly of one polarity, which is designated arbitrarily as positive (+). However, tissues in which a small satellite RNA and its associated plant virus are replicating have satellite RNAs of both polarities. Similarly, both polarities of viroid RNA accumulate during infections. The first satellite RNA demonstrated to undergo autolytic processing was the dimeric form of the 359 nt sTobRV(+) RNA purified from encapsidated RNA. The generated monomeric sTobRV(+) RNA was at least as biologically active as the dimeric RNA from which the monomeric RNA was derived.