RADIATION MUTAGENESIS - THE INITIAL DNA LESIONS RESPONSIBLE - COMMENTARY

This paper is an attempt to initiate a discussion about the causes of radiation-induced mutagenesis. It considers the evidence for the invol vement of singly base-damaged sites as sources of this mutagenesis. Se veral sets of published data are examined: These include endogenous le vels of oxidized bases and their production by natural oxidative proce sses, and yields of mutants produced by hydrogen peroxide and by high- LET radiation. These considerations lead to the conclusion that, at th e levels at which they are produced by ionizing radiation, DNA base-da maged sites are not a cause of radiation-induced mutagenesis. In analo gy with previous work we invoke the involvement of multiply damaged si tes (such as double-strand breaks) produced by radiation as the causat ive lesions. (C) 1995 by Radiation Research Society