Radiation-induced recombination is dependent on Ku80

We have recently shown that irradiating cells prior to transfection induces recombination, as manifested by increased stable transduction of both plas mid and adenoviral vectors. We hypothesized that Ku proteins, which have pr eviously been shown to be involved in both recombination and the repair of DNA damage after irradiation, would likely be important mediators of radiat ion-induced recombination, The present work demonstrates that Ku80 is essen tial for radiation-induced recombination, While human and hamster Ku80 are equally effective at restoring the transfection efficiency and radiation re sistance of xrs-5 cells, human Ku80 is much more effective at radiation-ind uced recombination than hamster Ku80. This difference is not due to differe nces in Ku80 expression or DNA end-binding activity, but it may be due to s tructural differences between human and hamster Ku80, (C) 1999 by Radiation Research Society.