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Reference: Eissenberg JC, et al. (1997) Mutations in yeast proliferating cell nuclear antigen define distinct sites for interaction with DNA polymerase delta and DNA polymerase epsilon. Mol Cell Biol 17(11):6367-78

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Abstract

The importance of the interdomain connector loop and of the carboxy-terminal domain of Saccharomyces cerevisiae proliferating cell nuclear antigen (PCNA) for functional interaction with DNA polymerases delta (Poldelta) and epsilon (Pol epsilon) was investigated by site-directed mutagenesis. Two alleles, pol30-79 (IL126,128AA) in the interdomain connector loop and pol30-90 (PK252,253AA) near the carboxy terminus, caused growth defects and elevated sensitivity to DNA-damaging agents. These two mutants also had elevated rates of spontaneous mutations. The mutator phenotype of pol30-90 was due to partially defective mismatch repair in the mutant. In vitro, the mutant PCNAs showed defects in DNA synthesis. Interestingly, the pol30-79 mutant PCNA (pcna-79) was most defective in replication with Poldelta, whereas pcna-90 was defective in replication with Pol epsilon. Protein-protein interaction studies showed that pcna-79 and pcna-90 failed to interact with Pol delta and Pol epsilon, respectively. In addition, pcna-90 was defective in interaction with the FEN-1 endo-exonuclease (RTH1 product). A loss of interaction between pcna-79 and the smallest subunit of Poldelta, the POL32 gene product, implicates this interaction in the observed defect with the polymerase. Neither PCNA mutant showed a defect in the interaction with replication factor C or in loading by this complex. Processivity of DNA synthesis by the mutant holoenzyme containing pcna-79 was unaffected on poly(dA) x oligo(dT) but was dramatically reduced on a natural template with secondary structure. A stem-loop structure with a 20-bp stem formed a virtually complete block for the holoenzyme containing pcna-79 but posed only a minor pause site for wild-type holoenzyme, indicating a function of the POL32 gene product in allowing replication past structural blocks.

Reference Type
Journal Article | Research Support, U.S. Gov't, P.H.S.
Authors
Eissenberg JC, Ayyagari R, Gomes XV, Burgers PM
Primary Lit For
POL30 | POL32 | PCNA homotrimer | DNA replication factor C complex
Additional Lit For
RAD27

Interaction Annotations

Genetic Interactions

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Interactor Interactor Allele Assay Annotation Action Phenotype SGA score P-value Source Reference

Physical Interactions 1 entry for 2 genes

Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

InteractorInteractorAssayAnnotationActionModification
POL30POL32Reconstituted Complexmanually curatedBait-HitNo Modification
Showing 1 to 1 of 1 entries