Penetration and Fate of Exogenous DNA in Cells of Normal and Irradiated Mammalian Tissues.

Labelled bacterial DNA introduced into rats via the carotid is at once distributed among different organs, some becoming progressively incorporated in the endogenous DNA. These and other results suggest that double stranded endogenous and exogenous DNAs are covalently combined. Heavy labelled molecules can be found in DNA prepared from organs of rats infused with unlabelled Micrococcus lysodeikticus DNA and tritiated thymidine. In ascites tumour cells, pentobarbital decreases incorporation of tritiated thymidine without modifying uptake of labelled bacterial DNA. On the other hand, DEAE-dextran increases uptake of bacterial DNA, but DNase removes 90 of the label taken up. The relationship of these results to the post-irradiation therapy with DNA is discussed. Author