Presence of an intron in inverted repeat constructs does not necessarily have an effect on efficiency of post-transcriptional gene silencing

The effect of introns on silencing efficiency was tested in inverted repeat constructs of Granule-Bound Starch Synthase (GBSSI) cDNA by comparing the silencing efficiencies induced by inverted repeat constructs with and without introns. No effect could be attributed to the presence of introns indicating that the introns neither enhance nor inhibit post-transcriptional gene silencing. The effect of a spliceable intron in the spacer was studied by comparing constructs harbouring a spliceable or a non-spliceable intron in the spacer. As opposed to the general belief that splicing of an intron increases silencing efficiency, the use of a spliceable intron in the spacer did not result in enhancement of silencing in our experimental system