Genomic DNA Regions Whose Complementary Strands Are Prone to UV Light-Induced Crosslinking

We prepared an extensive set of DNA restriction fragments, irradiated them with UV light, and detected crosslinked complementary strands by electrophoresis in denaturing agarose gels. These experimental data were quantified by densitometry to determine tetranucleotide contributions to crosslinking. The tetranucleotide contributions were used to predict genomic maps of the crosslinking probability that permitted us to identify two strongly crosslinking genomic regions having 295 and 389 base pairs in length. The two sequences shared the (ATTTTATA).(TATAAAAT) octamer, which is a candidate for the hotspot of UV light-induced crosslinking between the complementary strands of DNA.