The double-stranded DNA copy corresponding to the 5′-nontranslated αβ-leader of potato virus X (PVX) genomic RNA (positions −3 to −85 according to AUG initiator) was chemically synthesized and fused to the transcription plasmids containing three different reporter genes: neomycinphosphotransferase type II (NPT II) gene, Bacillus thuringiensis coleopteran-specific toxic protein gene and β-glucuronidase (GUS) gene. Expression of the reporter genes in vitro and in plant protoplasts (in the case of GUS gene) reveals that the αβ-leader of PVX RNA acts as a translation enhancer despite the presence of the upstream vector-derived sequence and irrespective of the length of the spacer sequence preceding the reporter genes.
