title: Pyrimidine dimer induction and repair in cultured human skin keratinocytes or melanocytes after irradiation with monochromatic ultraviolet radiation.
abstract: We compared the susceptibilities of cultured melanocytes and keratinocytes to dimer induction in DNA by monochromatic ultraviolet (UV) radiation. Keratinocytes as well as melanocytes were derived from human foreskin, grown as a monolayer in petri dishes, covered with phosphate-buffered saline containing 0.1% glucose, and irradiated. UV irradiation was carried out at 254, 297, and 302 nm as well as with a light source emitting predominantly 312 nm. The induction of pyrmidine dimers was assessed by determination of the number of T4 endonuclease V-sensitive sites (ESS). We found a slightly higher response for dimer induction in melanocytes at 254, 297, and 302 nm; this difference was only significant at the 297-nm wavelength. Action spectra for pyrimidine dimer induction were derived from the exposure-response data obtained. The action spectra mimic to a large degree the action spectra for dimer induction in other cultured mammalian cells. The repair rate during a post-irradiation period lasting up to 24 h was substantially the same for the two cell types. The percentage of T4 endonuclease V-sensitive sites (ESS) remaining 9 and 24 h after irradiation was 45% and 30%, respectively.
authors.affiliation: Department of Dermatology, University Hospital Leiden, The Netherlands.
authors.forename: A A
authors.initials: AA
authors.lastname: Schothorst
authors.forename: L M
authors.initials: LM
authors.lastname: Evers
authors.forename: K C
authors.initials: KC
authors.lastname: Noz
authors.forename: R
authors.initials: R
authors.lastname: Filon
authors.forename: A A
authors.initials: AA
authors.lastname: van Zeeland
mesh_terms: D002478:Cells, Cultured; D004247:DNA / Q000528:radiation effects; D004260:DNA Repair; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004706:Endodeoxyribonucleases / Q000096:biosynthesis; D006801:Humans; D015603:Keratinocytes / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D008544:Melanocytes / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D011740:Pyrimidine Dimers / Q000096:biosynthesis*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014764:Viral Proteins
chemical_list: D011740:Pyrimidine Dimers; D014764:Viral Proteins; D004247:DNA; D004706:Endodeoxyribonucleases; C470698:endonuclease V, phage T4; D043224:Deoxyribonuclease (Pyrimidine Dimer)