Inverted Complementary Terminal Sequences in Single-Stranded RNAs and Snap-Back RNAs from Vesicular Stomatitis Defective Interfering Particles

Abstract

Complementary single-stranded RNA from 3 independent VSV [vesicular stomatitis virus] defective interfering particle (DI) sources examined can anneal and give rise to monomeric and multimeric circular and linear double-stranded structures observable by EM under aqueous conditions. When the RNA from the shortest of these DI is spread from 80% formamide solutions, as many as 32% of the molecules are circular, suggesting that the single-stranded RNA contain inverted complementary terminal sequences. This is strongly supported by the isolation of the putative terminal sequences which rapidly become RNase resistant base-paired structures after melting and quick-cooling the RNA. RNase digestion yields a major and a minor component, 60-70 and 135-170 nucleotides long, respectively. Snap-back DI RNA also contain inverted complementary sequences at both ends of the plus and minus strands of the duplexes since nicking these at the ends gives rise to double-stranded molecules which can form monomeric and multimeric circular and linear molecules. Thus, snap-back molecules most likely contain a covalent linkage between or near complementary terminal sequences on the 2 complementary strands.