Telomeric sequences, radiation sensitivity and genomic instability

Purpose: To review the basic features of telomeres with particular emphasis on their potential importance in radiation biology. Recent findings sugges t that telomere length can influence radiation sensitivity in mouse and tha t several human radiosensitive disorders also show abnormalities in telomer e dynamics. Numerous studies indicate that telomeric sequences may play a r ole in determining the stability of certain genomic regions both spontaneou sly and following irradiation. Furthermore, a number of transmissible genom ic instability systems have been described in which it appears that telomer e metabolism may be contributing to the delayed effects observed. Features of telomeres and telomere biology relevant to these topics are reviewed. Conclusions: The evidence that telomeres and the molecular pathways of telo mere maintenance can play a role in determining the outcome of radiation ex posure is now substantial. Thus, the field of telomere biology deserves con tinued attention from radiobiologists.