Alkylation damage and DNA excision repair in mammalian cells

Publisher Website
Google Scholar
Abstract
Excision repair can be measured by using benzoylated naphthoylated DEAE cellulose (BND cellulose) to filter out DNA formed by replicative synthesis. A rapid batch method that permits analysis of many samples has been developed. Repair can be measured at growing points and in the bulk of the DNA. Using this technology, we have shown that the mutagen methyl nitronitrosoguanidine induces increased repair rates in DNA growing point regions. We have also observed that excision repair capability decreases as chick retinal tissues develop. “Glial‐like” cells growing out after trypsinization of the retinas are devoid of measurable repair activity. BND cellulose chromatography can also be used to detect interruptions in DNA. Treatment of cells with methyl methanesulfonate (MMS) leads to interruptions in cellular DNA, in contrast to treatment with acetoxy acetylaminofluorene (AAAF), which is an active repair‐inducing agent but which does not induce detectable numbers of breaks in cellular DNA. We conclude that there are at least two mechanisms for excision repair. The first, the MMS type, produces DNA with interruptions and inserts relatively few nucleotides. The second, the AAAF type, does not result in detectable interruptions in DNA and produces relatively long repair patches.