Schematic of the group I ( trans-splicing ) intron expression cassette. Each trans-splicing αDENV-U143 group I intron was tagged downstream of the ΔN Bax 3’ exon with the mCherry fluorescent marker gene expressed from the Drosophila C virus (DCV) IRES sequence. Expression of this construct was driven by the Drosophila melanogaster Actin 5c promoter (A5c). This bi-cistronic configuration allowed monitoring for the presence and expression of the anti-DENV group I intron constructs within cell cultures. A5c = Drosophila Actin 5c promoter, EGS = External guide sequence, IGS = Internal guide sequence, TSD = Trans-splicing domain, ΔN Bax = pro-apoptotic 3’ exon, IRES = Internal ribosome entry site.