ABSTRACT
Ultraviolet (UV) radiation contained in sunlight may be considered as one of the most frequently encountered deleteriousagent for DNA by living organisms.UV radiation has a few positive consequences like the production of vitamin D.It is veryl ikely to have been a major driving force in the evolution on early earth. However, UV exposure results mostly in numerous harmful e¨ects, including induction of skin cancer and skin aging in humans,but also impaired growing inplants or deleterious consequences in the environment.Consequently,UV-induced DNA damage has been a very active©eld of investigation for several decades.First identi©cation of the cyclobutane pyrimidine dimers(CPDs) was reported in the late 1950s,followed a few years later by that of(6-4)photo products.§ecellular response to UV radiation was likewise extensively investigated.DNA repair of UV-induced photo products was in particular the topic of numerous works,which led among other outstanding discoveries to the elucidation of the mechanism of nucleotideexcision repair(NER)through the study of thexeroderma pigmentosum syndrome.§epurpose of this review is to provide basic information on the photo chemistry of DNA with emphasis placed on the most recent aspects.Information is also provided on the basic molecular mechanisms of DNA repair.More biological aspects of repair and other important topics like mutagenesis or translesion synthesis are not addressed because of space limitations.
