Mammalian 8-Oxoguanine DNA Glycosylase 1 Incises 8-Oxoadenine Opposite Cytosine in Nuclei and Mitochondria, while a Different Glycosylase Incises 8-Oxoadenine Opposite Guanine in Nuclei
Year: 2003
Type: article
Abstract: Cells are continuously exposed to oxidative species, which cause several types of oxidative DNA lesions. Repair of some of these lesions has been well characterized but little is known about the repair of many DNA lesions. The oxidized adenine base, 7,8-dihydro-8-oxoadenine (8-oxoA), is a relatively common DNA lesion, which is believed to be mutagenic in mammalian cells. This study investigates repair of 8-oxoA in nuclear and mitochondrial mammalian extracts. In nuclei, 8-oxoA:C and 8-oxoA:G base pairs are recognized and cleaved; in contrast, only 8-oxoA:C base pairs are cleaved in mitochondria. High stability of the DNA helix increased the efficiency of incision of 8-oxoA, and the efficiency decreased at DNA bends and condensed regions of the helix. Using liver extracts from mice knocked out for 8-oxoguanine DNA glycosylase 1 (OGG1), we demonstrated that OGG1 is the only glycosylase that incises 8-oxoA, when base-paired with cytosine in mitochondria and nuclei, but a different enzyme incises 8-oxoA when base-paired with guanine in the nucleus. Consistent with this result, a covalent DNA-protein complex was trapped using purified human OGG1 or human nuclear or mitochondrial extracts with a DNA substrate containing an 8-oxoA:C base pair.
Source: Journal of Biological Chemistry
Authors: Anne Jensen, Guillaume Calvayrac, Bensu Karahalil, Vilhelm A. Bohr, Tinna Stevnsner
Language: English
Topic: DNA Repair Mechanisms
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1989311636