DNA primase stimulatory factor from mouse FM3A cells has an RNase H activity. Purification of the factor and analysis of the stimulation

J Biol Chem. 1990 Jun 25;265(18):10210-6.


Two forms of DNA primase stimulatory factor have been purified from mouse FM3A cells and shown to have RNase H activity. One of the factors, which consists of three polypeptides of 42,000, 41,000, and 27,000 daltons, was characterized in its properties as RNase H and DNA primase stimulatory factor. The nucleolytic activity of the factor specifically digested the RNA component of RNA-DNA hybrids in an endonucleolytic manner. The stimulation by the factor was observed in DNA synthesis by DNA primase-DNA polymerase alpha complex on unprimed DNA templates, and the DNA chains synthesized under these conditions in the presence of the factor were much shorter than those synthesized in its absence. The stimulatory effect of the factor on DNA primase activity was directly confirmed with DNA primase dissociated from DNA polymerase alpha by the observation of the increase in the number of synthesized oligoribonucleotides. The primer RNA synthesis by DNA primase-DNA polymerase alpha complex under the condition where DNA synthesis occurred was also significantly stimulated by the factor. Furthermore, under these conditions RNA primers were removed from DNA chains by the RNase H activity of the factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Chromatography
  • Chromatography, Ion Exchange
  • DNA Polymerase II / metabolism
  • DNA Primase
  • DNA Replication*
  • Durapatite
  • Endoribonucleases
  • Exoribonucleases / metabolism*
  • Hydroxyapatites
  • Kinetics
  • Mice
  • Molecular Weight
  • Oligodeoxyribonucleotides / biosynthesis
  • Oligonucleotides / biosynthesis
  • RNA Nucleotidyltransferases / metabolism*
  • Ribonuclease H
  • Substrate Specificity


  • Hydroxyapatites
  • Oligodeoxyribonucleotides
  • Oligonucleotides
  • Durapatite
  • DNA Primase
  • RNA Nucleotidyltransferases
  • DNA Polymerase II
  • Endoribonucleases
  • Exoribonucleases
  • exoribonuclease II
  • Ribonuclease H