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RAD18‐independent ubiquitination of proliferating‐cell nuclear antigen in the avian cell line DT40
Author(s) -
Simpson Laura J,
Ross AnnaLaura,
Szüts Dávid,
Alviani Cherry A,
Oestergaard Vibe H,
Patel Ketan J,
Sale Julian E
Publication year - 2006
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/sj.embor.7400777
Subject(s) - proliferating cell nuclear antigen , biology , ubiquitin , dna damage , microbiology and biotechnology , dna repair , mutation , dna , genetics , gene
Ubiquitination of proliferating‐cell nuclear antigen (PCNA) at K164 by RAD6/RAD18 has a key role in DNA damage tolerance in yeast. Here, we report on the first genetic study of this modification in a vertebrate cell. As in yeast, mutation of K164 of PCNA to arginine in the avian cell line DT40 results in sensitivity to DNA damage but, by contrast, the DT40 pcnaK164R mutant is more sensitive than the rad18 mutant. Consistent with this, we show the presence of residual ubiquitination of PCNA at K164 in the absence of functional RAD18, suggesting the presence of an alternate PCNA ubiquitinating enzyme in DT40. Furthermore, RAD18 and PCNA K164 have non‐overlapping roles in the suppression of sister chromatid exchange in DT40, showing that RAD18 has other functions that do not involve the ubiquitination of PCNA.