Replication of poly dA and poly rA by a drosophila DNA polymerase

Nucleic Acids Res. 1978 Jul;5(7):2565-75. doi: 10.1093/nar/5.7.2565.


The activity of a 7.3S-8.3S Drosophila DNA polymerase was characterized in detail using poly dA.p(dT)[unk] and poly rA.p(dT)[unk]. With poly dA.p(dT)[unk], Mg(2+) ion was the preferred divalent cation, and enzyme activity was inhibited by K(+) ion and by spermidine. With poly rA.p(dT)[unk], Mn(2+) ion was the preferred divalent cation and enzyme activity was stimulated by K(+) ion and by spermidine. The dependence of enzyme activity on the concentration of primer-template and on the ratio of primer to template was the same in both reactions. The two enzyme activities were identically inhibited by N-ethylmaleimide. Poly dA was replicated extensively and poly rA was replicated partially. The activation energy for poly dA replication was twice that for poly rA replication. Enzyme activity with poly dA.p(dT)[unk] was more stable to thermal inactivation than was enzyme activity with poly rA.p(dT)[unk]. These studies suggest that the same enzyme responds to both the deoxy- and the ribohomopolymer template but that the mechanisms of replication may be different.

Publication types

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

MeSH terms

  • Cations, Divalent / pharmacology
  • Cations, Monovalent / pharmacology
  • DNA Replication*
  • DNA-Directed DNA Polymerase / metabolism*
  • Drosophila melanogaster / enzymology*
  • Nucleic Acid Synthesis Inhibitors
  • Poly A / metabolism
  • Poly T / biosynthesis
  • Polydeoxyribonucleotides / metabolism
  • Spermidine / pharmacology
  • Substrate Specificity
  • Temperature
  • Templates, Genetic


  • Cations, Divalent
  • Cations, Monovalent
  • Nucleic Acid Synthesis Inhibitors
  • Polydeoxyribonucleotides
  • Poly A
  • Poly T
  • DNA-Directed DNA Polymerase
  • Spermidine