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Binding of nuclear proteins associated with mammalian DNA repair to the mitomycin C‐DNA interstrand crosslink
Author(s) -
Warren Amy J.,
Ihnat Michael A.,
Ogdon Sara E.,
Rowell Erin E.,
Hamilton Joshua W.
Publication year - 1998
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/(sici)1098-2280(1998)31:1<70::aid-em10>3.0.co;2-m
Subject(s) - xeroderma pigmentosum , chinese hamster ovary cell , dna , nucleotide excision repair , dna repair , microbiology and biotechnology , dna damage , biology , mitomycin c , cell culture , chemistry , biochemistry , genetics
Mitomycin C (MMC) is a DNA crosslinking agent that is used in cancer chemotherapy. Unlike the DNA crosslinks formed by cisplatin or psoralen, which significantly distort the DNA helix, the MMC crosslink does not significantly disturb the B‐DNA helical structure. Nonetheless, MMC interstrand crosslinks and total MMC adducts are rapidly removed in vivo. We investigated whether mammalian nuclear proteins can recognize and bind to a model 23 bp DNA duplex containing a single MMC lesion. Electrophoretic mobility shift assays identified two complexes in nuclear extracts from rodent cell lines and three complexes in human cell lines, containing proteins that appeared to specifically recognize the MMC interstrand crosslink. Nuclear extracts from normal and excision repair‐defective mutant Chinese hamster ovary (CHO) cell lines, from human Xeroderma Pigmentosum (XP) complementation group A and E cell lines, and a Fanconi's Anemia cell line were also examined. The UV‐20 CHO line, defective in ERCC‐1, was missing one of the two rodent complexes. Two of the three human complexes were also absent in the XPA human cell line and the intensity of the third complex was significantly diminished. Based on these results, a model for MMC crosslink recognition is proposed in which ERCC‐1 and XPA each participate in formation of one or more multimeric complexes on the crosslinked DNA and XPA also aids in the formation, but is not a component of a higher molecularweight multimeric complex that may contain ERCC‐1. Environ. Mol. Mutagen. 31:70–81, 1998. © 1998 Wiley‐Liss, Inc.