Nucleoporins facilitate ORC loading onto chromatin

Cell Rep. 2022 Nov 8;41(6):111590. doi: 10.1016/j.celrep.2022.111590.

Abstract

The origin recognition complex (ORC) binds throughout the genome to initiate DNA replication. In metazoans, it is still unclear how ORC is targeted to specific loci to facilitate helicase loading and replication initiation. Here, we perform immunoprecipitations coupled with mass spectrometry for ORC2 in Drosophila embryos. Surprisingly, we find that ORC2 associates with multiple subunits of the Nup107-160 subcomplex of the nuclear pore. Bioinformatic analysis reveals that, relative to all modENCODE factors, nucleoporins are among the most enriched factors at ORC2 binding sites. Critically, depletion of the nucleoporin Elys, a member of the Nup107-160 complex, decreases ORC2 loading onto chromatin. Depleting Elys also sensitizes cells to replication fork stalling, which could reflect a defect in establishing dormant replication origins. Our work reveals a connection between ORC, replication initiation, and nucleoporins, suggesting a function for nucleoporins in metazoan replication initiation.

Keywords: CP: Molecular biology; DNA replication; drosophila; genome stability; nuclear pore.

Publication types

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

MeSH terms

  • Animals
  • Aquaporins* / genetics
  • Chromatin
  • DNA Replication
  • Drosophila / metabolism
  • Drosophila Proteins* / genetics
  • Drosophila Proteins* / metabolism
  • Nuclear Pore Complex Proteins / metabolism
  • Origin Recognition Complex / genetics
  • Origin Recognition Complex / metabolism
  • Replication Origin

Substances

  • Origin Recognition Complex
  • Nuclear Pore Complex Proteins
  • Chromatin
  • Nup107 protein, Drosophila
  • Aquaporins
  • Drosophila Proteins