UV-damaged DNA-binding activity (UV-DDB) is deficient in some xeroderma pigmentosum group E individuals due to mutation of the p48 gene, but its role in DNA repair has been obscure.
The p48 gene is required for expression of an ultraviolet radiation-damaged DNA binding activity and is disrupted by mutations in the subset of xeroderma pigmentosum group E cells that lack this activity.
No such effects were observed from expression of p48 containing single amino acid substitutions from XP group E cells that lacked binding activity, demonstrating that the p48 gene is defective in those cells.
These results demonstrate that p48 is required for DNA binding activity, but at the same time necessitate further definition of the genetic basis of XP group E.