The fidelity of DNA replication, particularly on GC-rich templates, is reduced by defects of the Fe-S cluster in DNA polymerase δ

Nucleic Acids Res. 2021 Jun 4;49(10):5623-5636. doi: 10.1093/nar/gkab371.

Abstract

Iron-sulfur clusters (4Fe-4S) exist in many enzymes concerned with DNA replication and repair. The contribution of these clusters to enzymatic activity is not fully understood. We identified the MET18 (MMS19) gene of Saccharomyces cerevisiae as a strong mutator on GC-rich genes. Met18p is required for the efficient insertion of iron-sulfur clusters into various proteins. met18 mutants have an elevated rate of deletions between short flanking repeats, consistent with increased DNA polymerase slippage. This phenotype is very similar to that observed in mutants of POL3 (encoding the catalytic subunit of Pol δ) that weaken binding of the iron-sulfur cluster. Comparable mutants of POL2 (Pol ϵ) do not elevate deletions. Further support for the conclusion that met18 strains result in impaired DNA synthesis by Pol δ are the observations that Pol δ isolated from met18 strains has less bound iron and is less processive in vitro than the wild-type holoenzyme.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalytic Domain
  • DNA Polymerase III / metabolism*
  • DNA Repair*
  • DNA Replication*
  • DNA-Directed DNA Polymerase / metabolism
  • Iron-Sulfur Proteins / metabolism*
  • Protein Binding
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Transcription Factors / metabolism*

Substances

  • Iron-Sulfur Proteins
  • MET18 protein, S cerevisiae
  • POL3 protein, S cerevisiae
  • Pol32 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • POL31 protein, S cerevisiae