SUNLIGHT-INDUCED DNA LESIONS - LESION STRUCTURE, MUTATION CHARACTERISTICS AND REPAIR

The UV part of sunlight is known to induce a variety of genome defects . These lesions are the major cause of skin cancer development. In ord er to counter such toxic effects cells have developed a number of soph isticated DNA repair systems, like nucleotide excision repair and phot oreactivation. The repair machinery is able to specifically recognize sunlight-induced DNA lesions and to subsequently remove this damage. M alfunctioning repair systems are responsible for the three rare geneti c diseases Xeroderma pigmentosum, Cockayne's syndrome, and trichothiod ystrophy. In this review article, the structure of the major sunlight- induced lesions will de discussed. An overview of the two major repair mechanisms, photoreactivation and excision repair, is given, and the effects of the DNA lesions on the p53 gene and on tumor genesis are di scussed.