Identification of a novel protein, PDIP38, that interacts with the p50 subunit of DNA polymerase δ and proliferating cell nuclear antigen

Li Liu, Esther M. Rodriguez-Belmonte, Nayef Mazloum, Bin Xie, Marietta Y.W.T. Lee

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The yeast two-hybrid screening method was used to identify novel proteins that associate with human DNA polymerase δ (pol δ). Two baits were used in this study. These were the large (p125) and small (p50) subunits of the core pol δ heterodimer. p50 was the only positive isolated with p125 as the bait. Two novel protein partners, named PDIP38 and PDIP46, were identified from the p50 screen. In this study, the interaction of PDIP38 with pol δ was further characterized. PDIP38 encodes a protein of 368 amino acids whose C terminus is conserved with the bacterial APAG protein and with the F box A protein. It was found that PDIP38 also interacts with proliferating cell nuclear antigen (PCNA). The ability of PDIP38 to interact with both the p50 subunit of pol δ and with PCNA was confirmed by pull-down assays using glutathione S-transferase (GST)-PDIP38 fusion proteins. The PCNA-PDIP38 interaction was also demonstrated by PCNA overlay experiments. The association of PDIP38 with pol δ was shown to occur in calf thymus tissue and mammalian cell extracts by GST-PDIP38 pull-down and coimmunoprecipitation experiments. PDIP38 was associated with pol δ isolated by immunoaffinity chromatography. The association of PDIP38 with pol δ could also be demonstrated by native gel electrophoresis.

Original languageEnglish
Pages (from-to)10041-10047
Number of pages7
JournalJournal of Biological Chemistry
Issue number12
Publication statusPublished - 21 Mar 2003
Externally publishedYes


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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