Repair of 254 nm ultraviolet-induced (6-4) photoproducts: monoclonal antibody recognition and differential defects in xeroderma pigmentosum complementation groups A, D, and variant.
Repair kinetics of ultraviolet (UV) light-induced (6-4) photoproducts in xeroderma pigmentosum complementation group A, D, and variant cells were studied by the enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody raised against (6-4) photoproducts, together with unscheduled DNA synthesis (UDS) and loss of T4 endonuclease V-susceptible sites (ESS). Group AXP35KO cells completely failed to repair both ESS (cyclobutane pyrimidine dimers) and antibody-recognizing (6-4) photoproducts until tested 24 h after irradiation, and had 2% early-time UDS. Group DXP43KO cells showed about 10% removal of both (6-4) photoproducts and ESS in 24 h, despite showing a residually higher level of 40% early-time and cumulative UDS. Thus, the results substantiated the extreme UV hypersensitivity of XP group A and D cells. However, XP52KO variant cells exhibited the normal level of UDS and ESS loss, but a slightly reduced repair of antibody-recognizing (6-4) photoproducts at 6 and 12 h after irradiation, which may account for a small UV hypersensitivity of the XP variant cells.
Hiramoto
T
T
Department of Dermatology, Kobe University, School of Medicine, Japan.
Matsunaga
T
T
Ichihashi
M
M
Nikaido
O
O
Fujiwara
Y
Y
Mishima
Y
Y
D000911:Antibodies, Monoclonal; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004260:DNA Repair; D004307:Dose-Response Relationship, Radiation; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000235:genetics / Q000503:physiopathology*
D000911:Antibodies, Monoclonal; D004247:DNA