The invention provides methods of preventing or treating a condition associated with DNA damage in an animal comprising the administration of a substance that interferes with the activity of the CUL4A ubiquitin ligase. The invention also provides a substance that interferes with the activity of CUL4A, as well as compositions comprising the interfering substance and a carrier. The substance of the invention preferably enhances nucleotide excision repair activity in an animal. The invention further provides methods of identifying substances that negatively or positively modulate the expression and/or activity of CUL4A.
