Replication-coupled repair of crotonaldehyde/acetaldehyde-induced guanine-guanine interstrand cross-links and their mutagenicity

Xiang Liu, Yanbin Lao, In Young Yang, Stephen S. Hecht, Masaaki Moriya

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


The repair of acetaldehyde/crotonaldehyde-induced guanine (N 2)-guanine (N2) interstrand cross-links (ICLs), 3-(2-deoxyribos-1-yl)-5,6,7,8-(N2-deoxyguanosyl)-6(R or 5)-methylpyrimido[1,2-α]purine-10(3H)-one, was studied using a shuttle plasmid bearing a site-specific ICL. Since the authentic ICLs can revert to monoadducts, a chemically stable model ICL, 1,3-bis(2′-deoxyguanos-N 2-yl)butane derivative, was also employed to probe the ICL repair mechanism. Since the removal of ICL depends on the nucleotide excision repair (NER) mechanism in Escherichia coli, the plasmid bearing the model ICL failed to yield transformants in NER-deficient host cells, proving the stability of this ICL in cells. The authentic ICLs yielded transformants in the NER-deficient hosts; therefore, these transformants are produced by plasmid bearing spontaneously reverted monoadducts. In contrast, in NER-deficient human cells, the model ICL was removed by an NER-independent repair pathway, which is unique to higher eukaryotes. This repair did not associate with a transcriptional event, but with replication. The analysis of repaired molecules revealed that the authentic and model ICLs were repaired mostly (>94%) in an error-free manner in both hosts. The major mutations that were observed were G → T transversions targeting the cross-linked dG located in the lagging strand template. These results support one of the current models for the mammalian NER-independent ICL repair mechanism, in which a DNA endonuclease(s) unhooks an ICL from the leading strand template at a stalled replication fork site by incising on both sides of the ICL and then translesion synthesis is conducted across the "half-excised" ICL attached to the lagging strand template to restore DNA synthesis.

Original languageEnglish (US)
Pages (from-to)12898-12905
Number of pages8
Issue number42
StatePublished - Oct 24 2006


Dive into the research topics of 'Replication-coupled repair of crotonaldehyde/acetaldehyde-induced guanine-guanine interstrand cross-links and their mutagenicity'. Together they form a unique fingerprint.

Cite this