Delta helicase is a 5' to 3' DNA helicase that partially co-purifies with DNA polymerase delta (pol delta) from fetal bovine thymus tissue. We describe the resolution of delta helicase from pol delta on heparin-agarose chromatography and its purification to apparent homogeneity by affinity purification on single-stranded DNA-cellulose chromatography, unique-sequence RNA-agarose chromatography, and ceramic hydroxyapatite chromatography. Delta helicase isolated from fetal bovine thymus had an apparent M(r) of 115 kDa in SDS-PAGE, and photo-crosslinked to [alpha-32P]ATP. Tandem mass spectrometry peptide mass data derived from the bovine polypeptide matched to human UPF1 (HUPF1), a 5' to 3' RNA and DNA helicase, and a requisite component of the mRNA surveillance complex. Antisera against HUPF1 cross-reacted with delta helicase on western analysis, and delta helicase activity was immunoinactivated by pre-incubation with antibodies to HUPF1, suggesting that delta helicase is the bovine homolog of HUPF1. Immunoprecipitation experiments demonstrated that HUPF1 interacts with the 66-kDa third subunit of pol delta in vivo.
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http://dx.doi.org/10.1093/nar/30.10.2232 | DOI Listing |
Nat Commun
December 2024
Department of Biology, Tufts University, Medford, MA, 02155, USA.
Trinucleotide repeats, including Friedreich's ataxia (GAA) repeats, become pathogenic upon expansions during DNA replication and repair. Here, we show that deficiency of the essential replisome component Mcm10 dramatically elevates (GAA) repeat instability in a budding yeast model by loss of proper CMG helicase interaction. Supporting this conclusion, live-cell microscopy experiments reveal increased replication fork stalling at the repeat in mcm10-1 cells.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Centre for Medicines Discovery, University of Oxford, Oxford OX3 7FZ, UK.
Multiple modes of DNA repair need DNA synthesis by DNA polymerase enzymes. The eukaryotic B-family DNA polymerase complexes delta (Polδ) and zeta (Polζ) help to repair DNA strand breaks when primed by homologous recombination or single-strand DNA annealing. DNA synthesis by Polδ and Polζ is mutagenic, but is needed for the survival of cells in the presence of DNA strand breaks.
View Article and Find Full Text PDFScand J Clin Lab Invest
October 2024
Department of Clinical Biochemistry, Hvidovre Hospital, Hvidovre, Denmark.
Proc Natl Acad Sci U S A
October 2024
Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80525.
Replication stress describes endogenous and exogenous challenges to DNA replication in the S-phase. Stress during this critical process causes helicase-polymerase decoupling at replication forks, triggering the S-phase checkpoint, which orchestrates global replication fork stalling and delayed entry into G2. The replication stressor most often used to induce the checkpoint response in yeast is hydroxyurea (HU), a clinically used chemotherapeutic.
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