Fig. 1.

Repair of UVB-induced CPD at nucleotide resolution along a portion of the TS of the human hprt gene in TK6, TK6-5E, and NH32. Repair rates at individual sites (exon 3, primer HC, nucleotides 16740–16880; GenBank accession no. M26939) are depicted for NH32 (Left), TK6-5E (Center), and TK6 (Right). The first four lanes on the left show LMPCR of DNA treated with standard Maxam–Gilbert cleavage reactions. For each strain, the following seven lanes show LMPCR of DNA isolated from UVB-irradiated cells that have undergone repair for the indicated times. The last lane for each strain shows LMPCR of unirradiated DNA followed by T4 endonuclease V/photolyase digestion (background). The arrows indicate dipyrimidine sites that were quantified using a GS-25 phosphorimager, equipped with multianalyst, Ver. 1.1 (Bio-Rad Canada).