TRANSFORMING POTENTIAL OF DNA PREPARATION S FROM TISSUES OF C57BI 6 MICE EXPOSED TO RADIATION AND CHEMICAL TREATMENT IN THE CONDITIONS OF LYMPHOMA INDUCTION/

By method of DNA-mediated transformation of immortalized NIH3T3 cells the transforming potential was registered in the DNA preparations from tissues of C57BI/6 mice exposed to gamma-radiation and N-methyl-N-nit rosourea (MNU) under conditions providing a high frequency of inductio n of lymphomas in survived animals. Such a methodic approach permitted to reveal the occurence of procarcinogenic lesions in the genome of h ematopoietic tissue cells of animals at earlier terms after irradiatio n than malignant lymphomas were diagnosed by traditional cytomorpholog ical methods. The transforming potential of DNA preparations 90 and 12 0 days after radiation lymphoma induction was higher for DNA preparati on from actively proliferating tissues of bone marrow, spleen and thym us than for those from liver and brain. A synergism of combined action of radiation and MNU was observed with respect to induction of transf oming activity of DNA preparation isolated from the bone marrow and th ymus.