Molecular determinants of phase separation for Drosophila DNA replication licensing factors

Matthew W. Parker, Jonchee Kao, Alvin Huang, James M. Berger, Michael R. Botchan

Research output: Contribution to journalArticlepeer-review

Abstract

Liquid-liquid phase separation (LLPS) of intrinsically disordered regions (IDRs) in proteins can drive the formation of membraneless compartments in cells. Phase-separated structures enrich for specific partner proteins and exclude others. Previously, we showed that the IDRs of metazoan DNA replication initiators drive DNA-dependent phase separation in vitro and chromosome binding in vivo, and that initiator condensates selectively recruit replication-specific partner proteins (Parker et al., 2019). How initiator IDRs facilitate LLPS and maintain compositional specificity is unknown. Here, using D. melanogaster (Dm) Cdt1 as a model initiation factor, we show that phase separation results from a synergy between electrostatic DNA-bridging interactions and hydrophobic inter-IDR contacts. Both sets of interactions depend on sequence composition (but not sequence order), are resistant to 1,6-hexanediol, and do not depend on aromaticity. These findings demonstrate that distinct sets of interactions drive condensate formation and specificity across different phaseseparating systems and advance efforts to predict IDR LLPS propensity and partner selection a priori.

Original languageEnglish (US)
Article numbere70535
JournaleLife
Volume10
DOIs
StatePublished - Dec 2021

Keywords

  • DNA binding proteins
  • DNA replication
  • Intrinsically disordered proteins
  • Liquid phase condensates

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

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