The catalytic subunit of @entity1 DNA polymerase (pol) delta was overexpressed in an active, soluble form by the use of a baculovirus system in insect cells. The recombinant enzyme was separated from endogenous DNA polymerases by phosphocellulose, Mono Q-Sepharose, and single-stranded DNA-cellulose chromatography. Recombinant DNA pol delta was also purified by immunoaffinity chromatography. The enzymatic properties of the purified catalytic subunit were characterized. The enzyme was active and possessed both DNA polymerase and associated 3' to 5' exonuclease activities. @entity2733 -terminal deletion mutants retained polymerase activity, whereas the core and @entity1473 -terminal deletion mutants were devoid of any measurable activities. Coinfection of Sf9 cells with recombinant baculovirus vectors for pol delta and cyclin-dependent kinase (cdk)-cyclins followed by metabolic labeling with 32Pi showed that the recombinant catalytic subunit of pol delta could be hyperphosphorylated by G1 phase-specific cdk-cyclins. When @entity15308 was coexpressed with pol delta in Sf9 cells, pol delta was found to coimmunoprecipitate with antibodies against @entity15308 . Experiments with deletion mutants of pol delta showed that the @entity2733 -terminal region was essential for this interaction. Coimmunoprecipitation and Western blot experiments in Molt 4 cells confirmed the interaction in vivo. Preliminary experiments showed that phosphorylation of the catalytic subunit of pol delta by @entity15308 -cyclins had little or no effect on the specific activity of the enzyme.

Characterization of the p125 subunit of XXXX DNA polymerase delta and its deletion mutants. Interaction with cyclin-dependent kinase-cyclins.

@entity1 :: ('9606', 'Species') :: ['human'] @entity15308 :: ('1017', 'Gene') :: ['cdk2'] @entity1473 :: ('CHEBI:46883', 'Chemical') :: ['COOH'] @entity2733 :: ('CHEBI:29345', 'Chemical') :: ['NH2']
@entity1 :: (9606,Species) :: ['human']
