Figure 2.

AON Treatment of Patient-Derived Fibroblasts

(A) Schematic drawing of the hypothesized action of AONs on the transcript processing of BBS1. AONs may interfere with binding of intronic splice enhancers (ISEs), the consequence of which would be increased levels of both exon 5 skipping and normal splicing of the mutated BBS1 pre-mRNA transcript. Green arrows show the hypothesized effect of the AON. The red letter A marks the mutated base pair in BBS1. (B) The patient-derived fibroblast cell line was treated with AON_1 in two concentrations (20 nM and 200 nM). The treatment resulted in reduced intron 5 retention and increased exon 5 skipping. Whether the amount of correctly spliced BBS1 transcripts was also increased upon the AON_1 treatment was less clear. The AON was applied to the patient-derived cells for 24 h, the cells were harvested, RNA was isolated, and RT-PCR was performed. CS, correctly spliced transcript; ES, exon skipping; IR, intron retention; kb, kilo bases.