Relationship between sedimentation behaviour of DNA-protein complexes and DNA single- and double-strand breaks after irradiation with gamma-rays, pulsed neutrons and 12C ions.
The sedimentation behaviour of DNA-protein complexes was studied following irradiation of Chinese hamster cells (V79-4) and human lymphocytes over a wide dose range of 137Cs gamma-rays, pulsed neutrons and accelerated 12C ions. We have shown that the decrease of relative sedimentation velocity of the complexes at low doses is related to the occurrence of single-strand breaks in DNA. Rejoining of the breaks during a repair period increases the sedimentation velocity. At higher doses of radiation, double-strand breaks lead to an increase of sedimentation velocity of DNA-protein complexes. A new method can be devised on the basis of these results enabling estimation of the yields of single- and double-strand breaks in DNA.
D000818:Animals; D002244:Carbon; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D002588:Cesium Radioisotopes; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000528:radiation effects*; D004277:DNA, Single-Stranded / Q000528:radiation effects*; D004278:DNA, Superhelical / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D007477:Ions; D008214:Lymphocytes; D009502:Neutrons; D011506:Proteins / Q000528:radiation effects*
D002588:Cesium Radioisotopes; D004277:DNA, Single-Stranded; D004278:DNA, Superhelical; D007477:Ions; D011506:Proteins; D002244:Carbon; D004247:DNA