Efficient cleavage of single and clustered AP site lesions within mono-nucleosome templates by CHO-K1 nuclear extract contrasts with retardation of incision by purified APE1

摘要: Clustered DNA damage is a unique characteristic of radiation-induced and the formation these sites poses serious challenge to cell’s repair machinery. Within cell compacted, with nucleosomes being first order higher level structure. However, few data are reported on efficiency clustered-lesion processing within nucleosomal templates. Here, we show retardation cleavage single AP site by purified APE1 when contained in DNA, compared an non-nucleosomal DNA. This seen was alleviated incubation CHO-K1 nuclear extract. When clustered containing bistranded were present efficient observed after treatment The resultant DSB led dissociating from histone core dispersion. damaged site/8-oxoG residues showed no but 8-oxoG excision, isolated lesions, thus not seen. An increased understanding environment may lead new strategies enhance cytotoxic effects radiotherapeutics.