Question 1

Which lesion measurement method should be chosen?

Accepted Answer

Antibody-based detection is accessible and suits relative comparisons across timepoints. Chromatography with mass detection gives absolute lesion numbers per genome and distinguishes the photoproduct classes cleanly. Sequencing of excised fragments maps repair across the genome but requires substantial material and analysis. The question determines the choice, and mixing methods across a study invites artefact.

Question 2

How should a repair time course be designed?

Accepted Answer

Repair of one photoproduct class is largely complete within hours while the other persists far longer, so a single late timepoint conflates them. Dense early sampling captures the fast phase, with sparser later points defining the slow tail. Reporting the fraction remaining rather than raw signal makes comparisons across doses interpretable.

Question 3

Why does chromatin context matter for repair rate?

Accepted Answer

Damaged bases within nucleosomes and in compact regions are less accessible to the recognition machinery, so repair proceeds faster in transcribed and open regions. A genome-average rate therefore hides a wide distribution. Where the claim concerns accessibility, methods resolving repair by genomic region are needed rather than bulk measurement.

Question 4

What limits delivery of repair enzymes to skin?

Accepted Answer

The stratum corneum blocks most macromolecules, so a formulation working on cultured keratinocytes may never reach living cells in intact skin. Reconstructed epidermis models include the barrier and are the minimum credible test. Penetration depth should be measured directly rather than inferred from a downstream repair effect.

Question 5

Why is dosimetry reported so inconsistently in this literature?

Accepted Answer

Sources differ in spectral output, and biological effect depends strongly on wavelength, so the same nominal energy produces different lesion yields on different equipment. Reporting the measured spectrum, delivered energy at the sample surface and the calibration method allows others to reproduce the exposure rather than approximate it.

Question 6

Which endpoints demonstrate genuine protection?

Accepted Answer

Faster lesion removal is a mechanistic observation, not a protective outcome. Mutation frequency at a reporter locus, clonogenic survival after exposure, and in longer studies tumour incidence in an appropriate model, connect repair enhancement to consequence. At least one such endpoint should accompany any protection claim.

Biotechnology

Biotechnology

Research Frontiers in Nucleotide Excision Repair Engineering