Characterization of X-ray-induced immunostaining of proliferating cell nuclear antigen in human diploid fibroblasts.
The repair of X-ray-induced DNA damage related to the proliferating cell nuclear antigen (PCNA) was characterized in human diploid fibroblasts by an indirect immunofluorescence method. PCNA staining induced by X rays was lost after DNase I treatment but not after RNase treatment. The staining was not induced when ATP was depleted or the temperature was lowered to 0 degrees C during the X irradiation. When cells were incubated at 37 degrees C after X irradiation, PCNA staining diminished gradually and was almost entirely absent 12-15 h later. On the other hand, PCNA staining persisted during aphidicolin treatment even 20 h after X irradiation. Induction of PCNA staining was not affected by the aphidicolin treatment. Cycloheximide treatment did not affect induction of the staining either, but did inhibit the disappearance of the staining. There was no difference in the staining pattern and time course of PCNA staining after X irradiation between normal and xeroderma pigmentosum group A (XP-A) cells. These results imply that PCNA-dependent, aphidicolin-sensitive DNA polymerases may be involved in repair of X-ray-induced DNA damage in vivo, but the repair initiation step could be different from that of nucleotide excision repair initiated by XP proteins.
Department of Dental Radiology and Radiation Research, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
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M
Miura
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T
Sasaki
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Y
Takasaki
D000255:Adenosine Triphosphate / Q000378:metabolism; D016590:Aphidicolin / Q000494:pharmacology; D002460:Cell Line; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D004171:Diploidy; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis / Q000378:metabolism* / Q000528:radiation effects; D012016:Reference Values; D012867:Skin; D014965:X-Rays; D014983:Xeroderma Pigmentosum
D018809:Proliferating Cell Nuclear Antigen; D016590:Aphidicolin; D000255:Adenosine Triphosphate; D004247:DNA