OGG1 initiates age-dependent CAG trinucleotide expansion in somatic cells.

ABSTRACT: Although oxidative damage has long been associated with ageing and neurological disease, mechanistic connections of oxidation to these phenotypes have remained elusive. Here we show that the age-dependent somatic mutation associated with Huntington's disease occurs in the process of removing oxidized base lesions, and is remarkably dependent on a single base excision repair enzyme, 7,8-dihydro-8-oxoguanine-DNA glycosylase (OGG1). Both in vivo and in vitro results support a 'toxic oxidation' model in which OGG1 initiates an escalating oxidation-excision cycle that leads to progressive age-dependent expansion. Age-dependent CAG expansion provides a direct molecular link between oxidative damage and toxicity in post-mitotic neurons through a DNA damage response, and error-prone repair of single-strand breaks.

SUBMITTER: Kovtun IV 

PROVIDER: S-EPMC2681094 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature