INDUCTION OF A PARTICULAR DELETION IN MITOCHONDRIAL-DNA BY X-RAYS DEPENDS ON THE INHERENT RADIOSENSITIVITY OF THE CELLS

We examined whether X radiation induces a particular deletion in the m itochondrial DNA (mtDNA) of the cells of two human squamous cell carci noma lines with different sensitivity to radiation and in a radiosensi tive ataxia telangiectasia (AT) cell line. We used polymerase chain re action (PCR) to quantify the accumulation of a particular 4977-bp dele tion (Delta mtDNA(4977)). PCR products of Delta mtDNA(4977) were detec table after exposure to 10 Gy in the radioresistant squamous cell carc inoma cells, 2 Gy in the radiosensitive squamous cell carcinoma cells and 1 Gy in the radiosensitive AT cells. These observations suggest th at ionizing radiation induces the Delta mtDNA(4977) in human cells and that the radiation doses required to induce this deletion reflect the sensitivity of cells to radiation. (C) 1997 by Radiation Research Soc iety.