Ultraviolet light induces DNA modifications/photprodcuts, which interfere with DNA replication and transcription.
Nucleotide excision repair (NER) removes these photoproducts, but whether NER functions at telomeres is unresolved.
Researchers use immunospot blotting to examine the efficiency of photoproduct formation and removal at telomeres purified from UVC irradiated cells at various recovery times.
Telomeres exhibit approximately twofold fewer photoproducts compared with the bulk genome in cells, and telomere-binding protein TRF1 significantly reduces photoproduct formation in telomeric fragments in vitro.
Authors show that photoprodcuts removal from telomeres occurs faster than the bulk genome, and provide new evidence that telomeres are partially protected from ultraviolet irradiation and that NER preserves telomere integrity.