A unique subpopulation of murine DNA polymerase alpha/primase specifically interacts with polyomavirus T antigen and stimulates DNA replication

Mol Cell Biol. 1994 Apr;14(4):2767-76. doi: 10.1128/mcb.14.4.2767-2776.1994.

Abstract

Murine cells or cell extracts support the replication of plasmids containing the replication origin (ori-DNA) of polyomavirus (Py) but not that of simian virus 40 (SV40), whereas human cells or cell extracts support the replication of SV40 ori-DNA but not that of Py ori-DNA. It was shown previously that fractions containing DNA polymerase alpha/primase from permissive cells allow viral ori-DNA replication to proceed in extracts of nonpermissive cells. To extend these observations, the binding of Py T antigen to both the permissive and nonpermissive DNA polymerase alpha/primase was examined. Py T antigen was retained by a murine DNA polymerase alpha/primase but not by a human DNA polymerase alpha/primase affinity column. Likewise, a Py T antigen affinity column retained DNA polymerase alpha/primase activity from murine cells but not from human cells. The murine fraction which bound to the Py T antigen column was able to stimulate Py ori-DNA replication in the nonpermissive extract. However, the DNA polymerase alpha/primase activity in this murine fraction constituted only a relatively small proportion (approximately 20 to 40%) of the total murine DNA polymerase alpha/primase that had been applied to the column. The DNA polymerase alpha/primase purified from the nonbound murine fraction, although far more replete in this activity, was incapable of supporting Py DNA replication. The two forms of murine DNA polymerase alpha/primase also differed in their interactions with Py T antigen. Our data thus demonstrate that there are two distinct populations of DNA polymerase alpha/primase in murine cells and that species-specific interactions between T antigen and DNA polymerases can be identified. They may also provide the basis for initiating a novel means of characterizing unique subpopulations of DNA polymerase alpha/primase.

Publication types

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

MeSH terms

  • Animals
  • Antigens, Polyomavirus Transforming / isolation & purification
  • Antigens, Polyomavirus Transforming / metabolism*
  • Cell Line
  • Chromatography, Affinity
  • DNA Primase
  • DNA Replication*
  • DNA, Viral / biosynthesis*
  • DNA-Directed DNA Polymerase / isolation & purification
  • DNA-Directed DNA Polymerase / metabolism*
  • HeLa Cells
  • Humans
  • Kinetics
  • Mice
  • Plasmids / biosynthesis
  • Polyomavirus / genetics
  • Protein Binding
  • RNA Nucleotidyltransferases / isolation & purification
  • RNA Nucleotidyltransferases / metabolism*
  • Simian virus 40 / genetics
  • Species Specificity

Substances

  • Antigens, Polyomavirus Transforming
  • DNA, Viral
  • DNA Primase
  • RNA Nucleotidyltransferases
  • DNA-Directed DNA Polymerase