The packaging capacity of recombinant adeno-associated viral (rAAV) vectors limits the size of the promoter that can be used to express the 4.43kb cystic fibrosis transmembrane conductance regulator (CFTR) cDNA. To circumvent this limitation, we screened a set of 100-mer synthetic enhancer elements, composed of ten 10 bp repeats, for their ability to augment CFTR transgene expression from a short 83 bp synthetic promoter in the context of a rAAV vector designed for use in the cystic fibrosis (CF) ferret model. Our initial studies assessing transcriptional activity in monolayer (non-polarized) cultures of human airway cell lines and primary ferret airway cells revealed that three of these synthetic enhancers (F1, F5, and F10) significantly promoted transcription of a luciferase transgene in the context of plasmid transfection. Further analysis in polarized cultures of human and ferret airway epithelia at an air-liquid interface (ALI), as well as in the ferret airway in vivo, demonstrated that the F5 enhancer produced the highest level of transgene expression in the context of an AAV vector. Furthermore, we demonstrated that increasing the size of the viral genome from 4.94 to 5.04 kb did not significantly affect particle yield of the vectors, but dramatically reduced the functionality of rAAV-CFTR vectors because of small terminal deletions that extended into the CFTR expression cassette of the 5.04 kb oversized genome. Since rAAV-CFTR vectors greater than 5 kb in size are dramatically impaired with respect to vector efficacy, we utilized a shortened ferret CFTR minigene with a 159 bp deletion in the R-domain to construct a rAAV vector (AV2/2.F5tg83-fCFTR∆R). This vector yielded an ~17-fold increase in expression of CFTR and significantly improved Cl- currents in CF ALI cultures. Our study has identified a small enhancer/promoter combination that may have broad utility for rAAV-mediated CF gene therapy to the airway.
This research output has an Altmetric Attention Score of 16. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 28 July 2026.
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#4
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Altmetric has tracked 32,151,140 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 91st percentile: it's in the top 10% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 3,368 research outputs from this source. They typically receive more attention than average, with a mean Attention Score of 9.4. This one has done well, scoring higher than 89% of its peers.
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