Beyond translesion synthesis: Polymerase κ fidelity as a potential determinant of microsatellite stability

Suzanne E. Hile, Xiaoxiao Wang, Marietta Y.W.T. Lee, Kristin A. Eckert

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Microsatellite DNA synthesis represents a significant component of human genome replication that must occur faithfully. However, yeast replicative DNA polymerases do not possess high fidelity for microsatellite synthesis. We hypothesized that the structural features of Y-family polymerases that facilitate accurate translesion synthesis may promote accurate microsatellite synthesis. We compared human polymerases κ (Pol κ) and η (Pol η) fidelities to that of replicative human polymerase δ holoenzyme (Pol δ4), using the in vitro HSV-tk assay. Relative polymerase accuracy for insertion/deletion (indel) errors within 2-3 unit repeats internal to the HSV-tk gene concurred with the literature: Pol δ4 >> Pol κ or Pol η. In contrast, relative polymerase accuracy for unit-based indel errors within [GT]10 and [TC]11 microsatellites was: Pol κPol δ4>Pol η. The magnitude of difference was greatest between Pols κ and δ4 with the [GT] template. Biochemically, Pol κ displayed less synthesis termination within the [GT] allele than did Pol δ4. In dual polymerase reactions, Pol κ competed with either a stalled or moving Pol δ4, thereby reducing termination. Our results challenge the ideology that pol κ is error prone, and suggest that DNA polymerases with complementary biochemical properties can function cooperatively at repetitive sequences.

Original languageEnglish (US)
Pages (from-to)1636-1647
Number of pages12
JournalNucleic acids research
Issue number4
StatePublished - Feb 2012

All Science Journal Classification (ASJC) codes

  • Genetics


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