Search

Ultraviolet light (UV) is one of the most common DNA damaging agents in the human environment. This paper examined the influence of DNA methylation on the level of UVB- and UVC-induced DNA damage. A purified DNA sequence containing CpG dinucleotides was methylated with a CpG methylase. We employed the linear amplification technique and the end-labelling approach followed by capillary electrophoresis with laser-induced fluorescence to investigate the sequence specificity of UV-induced DNA damage. The linear amplification technique mainly detects cyclobutane pyrimidine dimer (CPD) adducts, while the end-labelling approach mainly detects 6–4 photoproduct (6–4PP) lesions. The levels of CPD and 6–4PP adducts detected in methylated/unmethylated labelled sequences were analysed. The comparison showed that 5-methyl-cytosine significantly reduced the level of both CPD and 6–4PP adducts after UVB (308 nm) and UVC (254 nm) irradiation compared with the non-methylated counterpart. • DNA methylation decreased the level of UVB- and UVC-induced DNA damage. • Cyclobutane pyrimidine dimers were investigated using sequencing technology. • Pyrimidine (6–4)pyrimidone photoproducts were also examined. • DNA methylation decreased the level of UVB- and UVC-induced CPD adducts. • DNA methylation also decreased the level of UVB- and UVC-induced 6–4PP lesions. [ABSTRACT FROM AUTHOR]

Complexes incorporating a threading anthraquinone intercalator with pyrrole lexitropsin and platinum(II) moieties attached were developed with the goal of generating novel DNA binding modes, including the targeting of AT-rich regions in order to have high cytotoxicities. The binding of the complexes to DNA has been investigated and profiles surprisingly similar to that for cisplatin were observed; the profiles were different to those for a complex lacking the pyrrole lexitropsin component. The lack of selective binding to AT-rich regions suggests the platinum binding was dominating the sequence selectivity, and is consistent with the pyrrole lexitropsin slowing intercalation. The DNA unwinding profiles following platinum binding were evaluated by gel electrophoresis and suggested that intercalation and platinum binding were both occurring. [ABSTRACT FROM AUTHOR]