Repair and Replication of X-irradiated HeLa Cell DNA

Abstract
Non-semi-conservative DNA synthesis assayed by CsCl density gradient analysis has been detected in synchronous G1-phase HeLa cells irradiated with less than 1000 rads x-rays. The dose response is linearly proportional up to 5000 rads. A time course study shows the ‘repair’ is completed during 1–2 hours after irradiation. 80 per cent of the ‘repaired’ DNA is subsequently replicated.