Rad18 guides polη to replication stalling sites through physical interaction and PCNA monoubiquitination

Kenji Watanabe, Satoshi Tateishi, Michio Kawasuji, Toshiki Tsurimoto, Hirokazu Inoue, Masaru Yamaizumi

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476 Citations (Scopus)


The DNA replication machinery stalls at damaged sites on templates, but normally restarts by switching to a specialized DNA polymerase(s) that carries out translesion DNA synthesis (TLS). In human cells, DNA polymerase η (polη) accumulates at stalling sites as nuclear foci, and is involved in ultraviolet (UV)-induced TLS. Here we show that polη does not form nuclear foci in RAD18-/- cells after UV irradiation. Both Rad18 and Rad6 are required for polη focus formation. In wild-type cells, UV irradiation induces relocalization of Rad18 in the nucleus, thereby stimulating colocalization with proliferating cell nuclear antigen (PCNA), and Rad18/Rad6-dependent PCNA monoubiquitination. Purified Rad18 and Rad6B monoubiquitinate PCNA in vitro. Rad18 associates with polη constitutively through domains on their C-terminal regions, and this complex accumulates at the foci after UV irradiation. Furthermore, polη interacts preferentially with monoubiquitinated PCNA, but polδ does not. These results suggest that Rad18 is crucial for recruitment of polη to the damaged site through protein-protein interaction and PCNA monoubiquitination.

Original languageEnglish
Pages (from-to)3886-3896
Number of pages11
JournalEMBO Journal
Issue number19
Publication statusPublished - Oct 1 2004

All Science Journal Classification (ASJC) codes

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry,Genetics and Molecular Biology
  • General Immunology and Microbiology


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