Identification of delta helicase as the bovine homolog of HUPF1: demonstration of an interaction with the third subunit of DNA polymerase delta

Nucleic Acids Res. 2002 May 15;30(10):2232-43. doi: 10.1093/nar/30.10.2232.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / isolation & purification*
  • Adenosine Triphosphatases / metabolism
  • Amino Acid Sequence
  • Animals
  • Blotting, Western
  • Cattle
  • Chromatography / methods
  • DNA Helicases / genetics
  • DNA Helicases / isolation & purification*
  • DNA Helicases / metabolism
  • DNA Polymerase III / genetics
  • DNA Polymerase III / isolation & purification
  • DNA Polymerase III / metabolism
  • HeLa Cells
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Humans
  • Mass Spectrometry / methods
  • Molecular Sequence Data
  • Precipitin Tests
  • Protein Binding
  • Protein Subunits
  • RNA Helicases / genetics
  • RNA Helicases / metabolism*
  • Ribonucleoproteins / isolation & purification
  • Ribonucleoproteins / metabolism
  • Trans-Activators


  • Heterogeneous-Nuclear Ribonucleoproteins
  • Protein Subunits
  • Ribonucleoproteins
  • Trans-Activators
  • DNA Polymerase III
  • Adenosine Triphosphatases
  • DNA Helicases
  • RNA Helicases
  • UPF1 protein, human