Humanizing the yeast origin recognition complex

Nat Commun. 2021 Jan 4;12(1):33. doi: 10.1038/s41467-020-20277-y.

Abstract

The Origin Recognition Complex (ORC) is an evolutionarily conserved six-subunit protein complex that binds specific sites at many locations to coordinately replicate the entire eukaryote genome. Though highly conserved in structure, ORC's selectivity for replication origins has diverged tremendously between yeasts and humans to adapt to vastly different life cycles. In this work, we demonstrate that the selectivity determinant of ORC for DNA binding lies in a 19-amino acid insertion helix in the Orc4 subunit, which is present in yeast but absent in human. Removal of this motif from Orc4 transforms the yeast ORC, which selects origins based on base-specific binding at defined locations, into one whose selectivity is dictated by chromatin landscape and afforded with plasticity, as reported for human. Notably, the altered yeast ORC has acquired an affinity for regions near transcriptional start sites (TSSs), which the human ORC also favors.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Binding Sites
  • DNA, Fungal / metabolism
  • G2 Phase / genetics
  • Genome, Fungal
  • Humans
  • Models, Genetic
  • Mutation / genetics
  • Nucleosomes / metabolism
  • Nucleotide Motifs / genetics
  • Origin Recognition Complex / chemistry
  • Origin Recognition Complex / metabolism*
  • S Phase
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Stochastic Processes
  • Transcription Initiation Site

Substances

  • DNA, Fungal
  • Nucleosomes
  • Origin Recognition Complex
  • Saccharomyces cerevisiae Proteins