The telomere-associated proteins TRF1, TRF2 and TIN2 are recruited to UVA laser but not to ion-irradiated sites

DNA is compacted into chromosomes in the nucleus of cells. The ends of these chromosomes (telomeres) are associated to proteins to form a dynamic cap that protects the DNA from being viewed as double-strand breaks (DSBs) and eliciting a DNA damage response. One of the proteins responsible for telomere capping is TRF2 (telomeric repeat binding factor 2). Recently this protein was also reported to function in homologous recombination repair of DSBs [1] and its recruitment to sites of laser microirradiation supporting an involvement in DNA repair was observed [2,3]. Here we demonstrate that 337nm-laser irradiation induces a fast recruitment of TRF2 and other telomere-associated proteins as TRF1[4] and TIN2 (TRF1-interacting nuclear protein 2), whereas densely ionizing charged particle irradiation give no indication of accumulation at sites of damaged DNA[4].