Conformation of the 3'-end of beet necrotic yellow vein benevirus RNA 3 analysed by chemical and enzymatic probing and mutagenesis.

摘要

Secondary structure-sensitive chemical and enzymatic probes were used to produce a model for the folding of the last 68 residues of the 3'-non-coding region of beet necrotic yellow vein benevirus [beet necrotic yellow vein furovirus] RNA 3. The structure consisted of 2 stem-loops separated by a single-stranded region. RNA 3-derived transcripts were produced which contained mutations which either disrupted base pairing in the helices or maintained the helices but with alterations in the base pairingscheme. Other mutants contained substitutions in single-stranded regions (loops or bulged sequences). With a few exceptions, all 3 types of mutation abolished RNA 3 replication in vivo, suggesting that secondary structure and specific sequences are required for efficient recognition of the 3'-terminal region of RNA 3 by viral RNA-dependent RNA polymerase.