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Induction of proliferating cell nuclear antigen (PCNA) complex formation in quiescent fibroblasts from a xeroderma pigmentosum patient
Author(s) -
Miura Masahiko,
Domon Masaharu,
Sasaki Takehito,
Takasaki Yoshinari
Publication year - 1992
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041500221
Subject(s) - proliferating cell nuclear antigen , xeroderma pigmentosum , dna replication , microbiology and biotechnology , biology , dna repair , bromodeoxyuridine , dna , dna polymerase , dna synthesis , thymidine , cell growth , genetics
Accumulated evidence indicates that proliferating cell nuclear antigen (PCNA) is an auxiliary protein of DNA polymerase δ and forms tight association with DNA replication sites during DNA replication or DNA repair synthesis. In this study, such PCNA complex formation was investigated by the indirect immunofluorescence method, using both normal human fibroblasts and those derived from a xeroderma pigmentosum group A (XP‐A) patient. XP‐A fibroblasts in both proliferating and quiescent states did not show any differences from normal fibroblasts in the properties of PCNA‐staining in the untreated conditions. The PCNA complex formation was induced in quiescent normal fibroblasts by both ultraviolet light (UV)‐ and X‐irradiation, whereas in XP‐A fibroblasts it was induced by X‐irradiation, but not by UV‐irradiation. However, PCNA complex was induced in quiescent XP‐A fibroblasts by UV‐irradiation when the cells had previously incorporated 5‐bromodeoxyuridine (BrdU). These observations indicate a close correlation of PCNA complex formation and unscheduled DNA synthesis (UDS). Thus, it was concluded that PCNA complex formation was commonly induced in at least three conditions to produce UDS in spite of different types of DNA damages and DNA repair mechanisms.