Defective DNA repair in cultured melanocytes from xeroderma pigmentosum patients

• Published in: Journal of dermatology Vol. 17; no. 8; p. 465
• Main Authors: Yamaguchi, J, Mamada, A, Kondo, S, Satoh, Y
• Format: Journal Article
• Language: English
• Published: England 01.08.1990
• Subjects: Adolescent; Adult; Autoradiography; Cells, Cultured; Child; Child, Preschool; DNA - biosynthesis; DNA - radiation effects; DNA Repair; Dose-Response Relationship, Radiation; Female; Fibroblasts - metabolism; Humans; Male; Melanocytes - metabolism; Ultraviolet Rays; Xeroderma Pigmentosum - genetics
• ISSN: 0385-2407
• DOI: 10.1111/j.1346-8138.1990.tb01677.x

The DNA repair of ultraviolet (UV)-induced damages in primary cultured melanocytes from xeroderma pigmentosum (XP) patients and normal subjects were studied by measuring unscheduled DNA synthesis (UDS) on autoradiographs. Melanocytes were cultured in alpha-minimum essential medium (alpha-MEM) supplemented with 10% fetal calf serum (FCS), 12-O-tetradecanoyl-phorbol-13 acetate (TPA), and geneticin. The levels of UDS in XP melanocytes were compared with those in normal melanocytes. In both normal and XP melanocytes, post-UV-UDS increased dose-dependently at doses of 5-10 J/m2. XP melanocytes exhibited various levels of defect in DNA repair, depending on the type of XP. Melanocytes from XP-A patients displayed very low levels of UDS, only 6.2-8.4% that of the normal melanocytes. However, UDS values in melanocytes from intermediate groups, XP-D, XP-E, and XP-F, were relatively high, 37.2-53.5% of the control in XP-D, 50.0-66.5% in XP-E, and 38.2-46.7% in XP-F, respectively. Melanocytes from XP-variant patients exhibited almost normal levels of UDS, 87.7-91.6% of those from normal subjects. The levels of UDS in XP melanocytes were very similar to those in fibroblasts isolated from the same specimens.