Restoration of proliferating cell nuclear antigen (PCNA) complex formation in xeroderma pigmentosum group A cells following cis-diamminedichloroplatinum (II)-treatment by cell fusion with normal cells.
We examined the role of the factor deficient in xeroderma pigmentosum group A (XP-A) cells in the formation of proliferating cell nuclear antigen (PCNA) complex with DNA in the DNA repair process in human fibroblasts following cis-diamminedichloroplatinum (CDDP)-treatment. Immunofluorescence staining after methanol fixation was used to detect the PCNA complex formation. When quiescent normal cells were PCNA-stained at 3 h after 100 microM CDDP treatment for 1 h, almost all nuclei of the cells showed a punctuated staining pattern. On the other hand, nuclei of XP-A cells were not stained. These results were the same with the findings following 10J/m2 of ultraviolet light (UV)-irradiation. The quantitative analysis of the PCNA immunofluorescence intensity of normal cells revealed that the mean intensity was increased by 4.8 times by the CDDP-treatment and 6.1 times by the UV-irradiation, compared with that of untreated cells. The intensities among nuclei ranged widely in both treatments. In contrast, the mean intensity was not increased in XP-A cells by the same treatments. However, when XP-A cells were fused with normal cells with polyethylene glycol (PEG) treatment, the nuclei of the XP-A cells showed positive PCNA-staining following CDDP-treatment or UV-irradiation in almost all cases. These results suggest that the PCNA complex formation may play a role in the DNA repair process after the step where the factor deficient in XP-A cells is involved following CDDP-treatment as well as following UV-irradiation.
Department of Dental Radiology and Radiation Research, Faculty of Dentistry, Tokyo Medical and Dental University.
M
M
Miura
M
M
Domon
T
T
Sasaki
S
S
Kondo
Y
Y
Takasaki
D002455:Cell Division; D002459:Cell Fusion; D002467:Cell Nucleus / Q000737:chemistry*; D002478:Cells, Cultured; D002945:Cisplatin / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism; D004260:DNA Repair; D005455:Fluorescent Antibody Technique; D006801:Humans; D009687:Nuclear Proteins / Q000032:analysis* / Q000737:chemistry; D018809:Proliferating Cell Nuclear Antigen; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000276:immunology / Q000378:metabolism*
D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D004247:DNA; D002945:Cisplatin