Qri7/OSGEPL, the mitochondrial version of the universal Kae1/YgjD protein, is essential for mitochondrial genome maintenance

Nucleic Acids Res. 2009 Sep;37(16):5343-52. doi: 10.1093/nar/gkp557. Epub 2009 Jul 3.


Yeast Qri7 and human OSGEPL are members of the orthologous Kae1(OSGEP)/YgjD protein family, the last class of universally conserved proteins without assigned function. Phylogenetic analyses indicate that the eukaryotic Qri7(OSGEPL) proteins originated from bacterial YgjD proteins. We have recently shown that the archaeal Kae1 protein is a DNA-binding protein that exhibits apurinic endonuclease activity in vitro. We show here that the Qri7/OSGEPL proteins localize in mitochondria and are involved in mitochondrial genome maintenance in two model eukaryotic organisms, Saccharomyces cerevisiae and Caenorhabditis elegans. Furthermore, S. cerevisiae Qri7 complements the loss of the bacterial YgjD protein in Escherichia coli, suggesting that Qri7/OSGEPL and YgjD proteins have retained similar functions in modern organisms. We suggest to name members of the Kae1(OSGEP)/YgjD family UGMP, for Universal Genome Maintenance Proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / classification
  • Bacterial Proteins / genetics
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / ultrastructure
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / physiology*
  • DNA, Mitochondrial / analysis
  • Escherichia coli Proteins / genetics
  • Ethidium / pharmacology
  • Genes, Lethal
  • Genome, Mitochondrial*
  • Longevity
  • Mitochondria / ultrastructure
  • Mitochondrial Proteins / classification
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / physiology*
  • Mutation
  • Oxidative Stress
  • Phylogeny
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / physiology*


  • Bacterial Proteins
  • Caenorhabditis elegans Proteins
  • DNA, Mitochondrial
  • Escherichia coli Proteins
  • Mitochondrial Proteins
  • Qri7 protein, C elegans
  • Qri7 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Ethidium