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Frameshift mutations induced by four isomeric nitroacridines and their des‐nitro counterpart in the lacZ reversion assay in Escherichia coli
Author(s) -
Hoffmann George R.,
Yin Catherine C.,
Terry Caitlin E.,
Ferguson Lynnette R.,
Denny William A.
Publication year - 2006
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.20171
Subject(s) - frameshift mutation , acridine , reversion , base pair , mutagenesis , chemistry , guanine , nitro , methylnitronitrosoguanidine , dna , stereochemistry , mutation , biology , nucleotide , biochemistry , genetics , gene , phenotype , alkyl , organic chemistry
Acridines are well‐known as compounds that intercalate noncovalently between DNA base pairs and induce ±1 frameshift mutations at sites of monotonous repeats of a single base. Reactive derivatives of acridines, including acridine mustards and nitroacridines, form covalent adducts in DNA and exhibit mutagenic properties different from the simple intercalators. We compared the frameshift mutagenicity of the cancer chemotherapy drug nitracrine (1‐nitro‐9‐(3′‐dimethylaminopropylamino)‐acridine), its des‐nitro counterpart 9‐(3′‐dimethylaminopropylamino)‐acridine (DAPA), and its 2‐, 3‐, and 4‐nitro isomers (2‐, 3‐, and 4‐nitro‐DAPA) in the lacZ reversion assay in Escherichia coli . DAPA is a simple intercalator, much like the widely studied 9‐aminoacridine. It most strongly induced ±1 frameshift mutations in runs of guanine residues and more weakly induced −1 frameshifts in a run of adenine residues. A nitro group in the 1, 3, or 4 position of DAPA reduced the yield of ±1 frameshift mutations. DAPA weakly induced −2 frameshifts in an alternating CG sequence. In contrast, nitracrine and its 3‐nitro isomer resembled the 3‐nitroacridine Entozon in effectively inducing −2 frameshift mutations. The 2‐ and 4‐nitro isomers were less effective than the 1‐ and 3‐nitro compounds in −2 frameshift mutagenesis. The results are interpreted with respect to intercalation, steric interactions, effects of base strength on DNA binding, enzymatic processing, and a slipped mispairing model of frameshift mutagenesis. Environ. Mol. Mutagen., 2006. © 2005 Wiley‐Liss, Inc.