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The replication factory targeting sequence/PCNA‐binding site is required in G 1 to control the phosphorylation status of DNA ligase I
Author(s) -
Rossi Rossella,
Villa Antonello,
Negri Claudia,
Scovassi Ivana,
Ciarrocchi Giovanni,
Biamonti Giuseppe,
Montecucco Alessandra
Publication year - 1999
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/18.20.5745
Subject(s) - dna ligase , biology , proliferating cell nuclear antigen , dna replication , ubiquitin ligase , microbiology and biotechnology , replication factor c , dephosphorylation , dna clamp , eukaryotic dna replication , dna , phosphorylation , biochemistry , ubiquitin , gene , phosphatase , reverse transcriptase , rna
The recruitment of DNA ligase I to replication foci in S phase depends on a replication factory targeting sequence that also mediates the interaction with proliferating cell nuclear antigen (PCNA) in vitro . By exploiting a monoclonal antibody directed at a phospho‐epitope, we demonstrate that Ser66 of DNA ligase I, which is part of a strong CKII consensus site, is phosphorylated in a cell cycle‐dependent manner. After dephosphorylation in early G 1 , the level of Ser66 phosphorylation is minimal in G 1 , increases progressively in S and peaks in G 2 /M phase. The analysis of epitope‐tagged DNA ligase I mutants demonstrates that dephosphorylation of Ser66 requires both the nuclear localization and the PCNA‐binding site of the enzyme. Finally, we show that DNA ligase I and PCNA interact in vivo in G 1 and S phase but not in G 2 /M. We propose that dephosphorylation of Ser66 is part of a novel control mechanism to establish the pre‐replicative form of DNA ligase I.