SirA inhibits the essential DnaA:DnaD interaction to block helicase recruitment during Bacillus subtilis sporulation

Winterhalter, Charles; Stevens, Daniel; Fenyk, Stepan; Pelliciari, Simone; Marchand, Elie; Soultanas, Panos; Ilangovan, Aravindan; Murray, Heath

Abstract

Bidirectional DNA replication from a chromosome origin requires the asymmetric loading of two helicases, one for each replisome. Our understanding of the molecular mechanisms underpinning helicase loading at bacterial chromosome origins is incomplete. Here we report both positive and negative mechanisms for directing helicase recruitment in the model organism Bacillus subtilis. Systematic characterization of the essential initiation protein DnaD revealed distinct protein interfaces required for homo-oligomerization, interaction with the master initiator protein DnaA, and interaction with the helicase co-loader protein DnaB. Informed by these properties of DnaD, we went on to find that the developmentally expressed repressor of DNA replication initiation, SirA, blocks the interaction between DnaD and DnaA, thereby restricting helicase recruitment from the origin during sporulation to inhibit further initiation events. These results advance our understanding of the mechanisms underpinning DNA replication initiation in B. subtilis, as well as guiding the search for essential cellular activities to target for antimicrobial drug design.

Citation

Winterhalter, C., Stevens, D., Fenyk, S., Pelliciari, S., Marchand, E., Soultanas, P., Ilangovan, A., & Murray, H. (2023). SirA inhibits the essential DnaA:DnaD interaction to block helicase recruitment during Bacillus subtilis sporulation. Nucleic Acids Research, 51(9), 4302-4321. https://doi.org/10.1093/nar/gkac1060

• Journal Article Type: Article
• Acceptance Date: Oct 22, 2022
• Online Publication Date: Nov 23, 2022
• Publication Date: May 22, 2023
• Deposit Date: Oct 27, 2022
• Publicly Available Date: Nov 23, 2022
• Journal: Nucleic Acids Research
• Print ISSN: 0305-1048
• Electronic ISSN: 1362-4962
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 51
• Issue: 9
• Pages: 4302-4321
• DOI: https://doi.org/10.1093/nar/gkac1060
• Keywords: Chromosome, DnaD, DnaA, SirA, helicase, origin, replication
• Public URL: https://nottingham-repository.worktribe.com/output/12898606
• Publisher URL: https://academic.oup.com/nar/article/51/9/4302/6842904?login=false