Small molecule CFTR Modulators target functional defects within the CFTR protein.
Three types of CFTR modulators have been developed: premature stop codon suppressors (A), correctors (B), and potentiators (C). These small molecules act by targeting the transcription, translation, protein processing, membrane trafficking, and ion transport functionality of the CFTR protein, respectively.
Gene correction approaches aim to repair the CFTR gene mutation directly at the endogenous chromosomal locus.
The use of mRNA-encoded site-specific nucleases (SSE) can introduce double-strand breaks (DSB) near the genetic defect(s). If a donor vector with corrected sequence is also delivered to the cell, it can be utilized as a template for homologous repair (HR) as the cell works to repair the DSB (A). Successful homology-directed repair (HDR) will result in a corrected chromosomal locus, even after the SSE and donor template delivery vehicles are no longer expressed (B).
Genome-Editing Nucleases: Mechanisms of Action.
An overview of the mechanisms of DNA binding and cleavage used by ZFNs (A), TALENs (B), CRISPR/Cas9 (C), the dimeric CRISPR RNA-guided FokI system (D) and meganucleases (E). PAM, protospacer adjacent motif; sgRNA, single guide RNA; RuvC, nuclease domain in Cas9 that cleaves the non-target strand of DNA; HNH, nuclease domain in Cas9 that cleaves the target strand of DNA.