Mutation Analysis of cis-Elements in the 3′- and 5′-Untranslated Regions of Satellite Tobacco Necrosis Virus Strain C RNA

Abstract

The putative, 3′-terminal stem-loop structure in satellite tobacco necrosis virus strain C (STNV-C) RNA constitutes an essential cis-acting structure for the promotion of negative-strand RNA synthesis and a single-stranded tail is also important. The putative, 5′-terminal stem-loop structure in STNV-C RNA is not essential for productive, plus-strand RNA accumulation but is required for optimal accumulation. Residues 2 and 3 are the minimal cis-acting sequences required for RNA synthesis. The RNA of chimeric mutants, which exchanged 3′- and 5′-untranslated regions between STNV-C and helper tobacco necrosis virus strain D RNAs, accumulated in protoplasts, implying similar replication mechanisms for both RNAs.