Increased repair in DNA growing point regions after treatment of human lymphoma cells with N-methyl-N'-nitro-N-nitrosoguanidine.
Benzoylated naphthoylated DEAE-cellulose columns can be used to separate DNA growing point regions from the bulk of the DNA. We used the columns to estimate DNA excision repair in both fractions. Repair induced by acetoxy acetyl aminofluorene (AAAF), bromomethyl benz(alpha) anthracene (BMBA), and methyl methanesulfonate (MMS) occurs to an equal extent in growing point and non-replicating regions of the DNA. Excision repair induced by methyl nitrosourea (MNNU) and methyl nitronitrosoguanidine (MNNG) occurs to a greater extent in growing point regions of the DNA. The overall amount of methyl nitronitrosoguanidine-induced alkylation is the same for replicating and non-replicating regions of the DNA treated in vitro. We conclude that there is some special interaction between methyl-nitronitrosoguanidine and the growing point region in vivo. We suppose that strand displacement and branch migration return DNA lesions at the growing point to a double stranded configuration at which repair is possible.
Department of Microbiology, University of Chicago, Chicago, Illinois 60637, USA.
D
D
Scudiero
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B
Strauss
D002455:Cell Division / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects*; D004261:DNA Replication / Q000187:drug effects; D004273:DNA, Neoplasm / Q000187:drug effects*; D006801:Humans; D008223:Lymphoma; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D008769:Methylnitronitrosoguanidine