Molecular determinants of phase separation for Drosophila DNA replication licensing factors

eLife

James M Berger¹  Matthew W Parker²  Jonchee A Kao³  Alvin Huang³  Michael R Botchan³ 

[1] Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, United States;Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States;Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States;

关键词: DNA replication;    liquid phase condensates;    intrinsically disordered proteins;    DNA binding proteins;    D. melanogaster;   

DOI  :  10.7554/eLife.70535

来源: eLife Sciences Publications, Ltd

【 摘 要 】

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 Drosophila 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 phase-separating systems and advance efforts to predict IDR LLPS propensity and partner selection a priori.

【 授权许可】

CC BY