Figure 1

The diagram of the 3′ UTR structures of BaMV and PVX and the various chimera constructs. (A) The primary sequence and secondary structure of the BaMV-3′ UTR. BaMV-3′ UTR consists of three small stem-loops forming a clover leaf-like structure (ABC domain in green), one major stem-loop including a buldge and an internal loop (D domain in orange), and a pseudoknot (E domain in blue). (B) The primary sequence and two alternative secondary structure of the PVX 3′ UTR in red without poly (A) and in black with poly (A) tail [20]. Numbering of the stem-loops (SL1-3) is as indicated. (C) Schematic representation of the chimeric constructs based on a full-length BaMV-S cDNA clone. Hatched blocks: the coding sequence upstream of the 3′ UTR of BaMV RNA; blocks in colors indicated different domains shown in (A); the PVX 3′ UTR sequence in red when inserted in the 3′ UTR of BaMV, in black when fused to the very 3′-end of chimera. All constructs have a 40-adenosine-tract followed by an EcoICR I cleavage site at it’s 3′-end. Construct designations are shown at the right with the full-length transcript for protoplast and plant inoculation and with the short transcript for in vitro replication assay.