Distinctive activities of DNA polymerases during human DNA replication

Anna K. Rytkönen, Markku Vaara, Tamar Nethanel, Gabriel Kaufmann, Raija Sormunen, Esa Läärä, Heinz Peter Nasheuer, Amal Rahmeh, Marietta Y.W.T. Lee, Juhani E. Syväoja, Helmut Pospiech

Research output: Contribution to journalArticlepeer-review


The contributions of human DNA polymerases (pols) α, δ and ε during S-phase progression were studied in order to elaborate how these enzymes co-ordinate their functions during nuclear DNA replication. Pol δ was three to four times more intensely UV cross-linked to nascent DNA in late compared with early S phase, whereas the cross-linking of pols α and ε remained nearly constant throughout the S phase. Consistently, the chromatin-bound fraction of pol δ, unlike pols α and ε, increased in the late S phase. Moreover, pol δ neutralizing antibodies inhibited replicative DNA synthesis most efficiently in late S-phase nuclei, whereas antibodies against pol ε were most potent in early S phase. Ultrastructural localization of the pols by immuno-electron microscopy revealed pol ε to localize predominantly to ring-shaped clusters at electron-dense regions of the nucleus, whereas pol δ was mainly dispersed on fibrous structures. Pol α and proliferating cell nuclear antigen displayed partial colocalization with pol δ and ε, despite the very limited colocalization of the latter two pols. These data are consistent with models where pols δ and ε pursue their functions at least partly independently during DNA replication.

Original languageEnglish
Pages (from-to)2984-3001
Number of pages18
JournalFEBS Journal
Issue number13
StatePublished - Jul 2006


  • Cell cycle
  • DNA polymerase
  • DNA replication
  • Electron microscopy
  • UV cross-linking


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