DciA, the Bacterial Replicative Helicase Loader, Promotes LLPS in the Presence of ssDNA

Stéphanie Marsin, Sylvain Jeannin, Sonia Baconnais, Hélène Walbott, Gérard Pehau-Arnaudet, Magali Noiray, Magali Aumont-Nicaise, Emil G.P. Stender, Claire Cargemel, Romain Le Bars, Eric Le Cam, Sophie Quevillon-Cheruel

Résultats de recherche: Contribution à un journalArticleRevue par des pairs

Résumé

The loading of the bacterial replicative helicase DnaB is an essential step for genome replication and depends on the assistance of accessory proteins. Several of these proteins have been identified across the bacterial phyla. DciA is the most common loading protein in bacteria, yet the one whose mechanism is the least understood. We have previously shown that DciA from Vibrio cholerae is composed of a globular domain followed by an unfolded extension and demonstrated its strong affinity for DNA. Here, we characterize the condensates formed by VcDciA upon interaction with a short single-stranded DNA substrate. We demonstrate the fluidity of these condensates using light microscopy and address their network organization through electron microscopy, thereby bridging events to conclude on a liquid–liquid phase separation behavior. Additionally, we observe the recruitment of DnaB in the droplets, concomitant with the release of DciA. We show that the well-known helicase loader DnaC from Escherichia coli is also competent to form these phase-separated condensates in the presence of ssDNA. Our phenomenological data are still preliminary as regards the existence of these condensates in vivo, but open the way for exploring the potential involvement of DciA in the formation of non-membrane compartments within the bacterium to facilitate the assembly of replication players on chromosomal DNA.

langue originaleAnglais
Numéro d'article168873
journalJournal of Molecular Biology
Volume437
Numéro de publication2
Les DOIs
étatPublié - 15 janv. 2025
Modification externeOui

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