FIGURE 1.

PVX Genome organization and cis-acting elements in the 3′ NTR. (A) The five ORFs are depicted as boxes, with sizes noted in kilodaltons. Probes for S1 nuclease assays are shown above the genome (P3 for minus-strand RNA detection) and below the genome (P1 for plus-strand RNA detection). Templates used for RdRp assays (pcr850, pcr200, and txt 193) are listed below the 3′ region of the genome as horizontal lines. (B) The secondary structure for the PVX 3′ NTR RNA, as determined by Pillai-Nair et al. (2003), is labeled to indicate the three stem–loops, SL1, SL2, and SL3. (C) The linear sequence for the 3′ NTR is shown, along with the hexanucleotide element (ACAUAA, starting with “*”), the U-rich element (UAUUUUCU, starting with the arrow), and the two near upstream elements (NUE1 and NUE2, starting with the caret). The region deleted in the Δ10 mutant is denoted by a bracket below the sequence.