Question 1

How is the target exon chosen for a given patient deletion?

Accepted Answer

Selection starts from the exact deletion boundaries in the patient genome. The candidate exon is the one whose removal restores an open reading frame across the resulting junction. Accessibility of the pre-messenger RNA region, presence of exonic splicing enhancers, and predicted secondary structure then narrow the sequence window before any synthesis begins.

Question 2

Which backbone chemistry should a doctoral project prioritise?

Accepted Answer

Phosphorodiamidate morpholino oligomers and 2-O-methyl phosphorothioate chemistries dominate the literature, and each carries distinct stability, charge and clearance behaviour. A doctoral project usually fixes one chemistry as the working platform and varies sequence, then treats conjugation strategies such as cell-penetrating peptides as a separate comparison rather than a confounded variable.

Question 3

Why does transcript skipping not translate into equivalent protein restoration?

Accepted Answer

Skipping measured at the transcript level reports splicing outcome only. Translation, protein folding, membrane localisation and turnover all intervene before dystrophin becomes detectable. Truncated protein may also lose antibody epitopes, understating apparent yield. Reporting both nested reverse transcription results and immunoblot or immunofluorescence quantification, with matched loading controls, keeps the two readouts interpretable.

Question 4

Which models are appropriate for preclinical validation?

Accepted Answer

Patient-derived myoblasts and differentiated myotubes give human sequence context for early screening. Humanised murine models carrying the human dystrophin sequence allow testing of the actual clinical candidate rather than a species surrogate. Standard dystrophic mouse strains remain useful for delivery, biodistribution and toxicity questions where exact sequence identity matters less.

Question 5

How should off-target risk be assessed?

Accepted Answer

Transcriptome-wide hybridisation screening for near-complementary sites is now a routine expectation. Candidates are checked for partial matches that could trigger unintended splice modulation or transcript degradation, and shortlisted risks are tested experimentally in the same cell system used for on-target work. Innate immune activation and renal accumulation are assessed separately.

Question 6

What quantification methods are expected for skipping efficiency?

Accepted Answer

Nested reverse transcription with primers flanking the target exon remains the reference method, quantified by capillary electrophoresis or digital droplet assays rather than gel densitometry alone. Reporting should state the percentage of skipped transcript relative to total, the primer positions used, and whether amplification bias toward shorter products was controlled.

Biotechnology

Biotechnology

Research Frontiers in Exon Skipping Oligonucleotide Therapeutics