Article

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

Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla 10595, USA.
Journal of Biological Chemistry (impact factor: 4.77). 04/2003; 278(12):10041-7. DOI:10.1074/jbc.M208694200 pp.10041-7
Source: PubMed

ABSTRACT The yeast two-hybrid screening method was used to identify novel proteins that associate with human DNA polymerase delta (pol delta). Two baits were used in this study. These were the large (p125) and small (p50) subunits of the core pol delta 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 delta 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 delta 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 delta 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 delta isolated by immunoaffinity chromatography. The association of PDIP38 with pol delta could also be demonstrated by native gel electrophoresis.

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Keywords

368 amino acids
 
bacterial APAG protein
 
calf thymus tissue
 
coimmunoprecipitation experiments
 
core pol delta heterodimer
 
F box
 
glutathione S-transferase
 
GST)-PDIP38 fusion proteins
 
human DNA polymerase delta
 
interact
 
mammalian cell
 
native gel electrophoresis
 
novel protein partners
 
novel proteins
 
PCNA-PDIP38 interaction
 
pol delta
 
positive
 
proliferating cell nuclear antigen
 
yeast two-hybrid screening method
 

Li Liu