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Doan A, Chatterjee S, Kothapalli R, Khan Z, Sen S, Kedei N, Jha JK, Chattoraj DK, Ramachandran R. The replication enhancer crtS depends on transcription factor Lrp for modulating binding of initiator RctB to ori2 of Vibrio cholerae. Nucleic Acids Res 2024; 52:708-723. [PMID: 38000366 PMCID: PMC10810183 DOI: 10.1093/nar/gkad1111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 10/28/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
Replication of Vibrio cholerae chromosome 2 (Chr2) initiates when the Chr1 locus, crtS (Chr2 replication triggering site) duplicates. The site binds the Chr2 initiator, RctB, and the binding increases when crtS is complexed with the transcription factor, Lrp. How Lrp increases the RctB binding and how RctB is subsequently activated for initiation by the crtS-Lrp complex remain unclear. Here we show that Lrp bends crtS DNA and possibly contacts RctB, acts that commonly promote DNA-protein interactions. To understand how the crtS-Lrp complex enhances replication, we isolated Tn-insertion and point mutants of RctB, selecting for retention of initiator activity without crtS. Nearly all mutants (42/44) still responded to crtS for enhancing replication, exclusively in an Lrp-dependent manner. The results suggest that the Lrp-crtS controls either an essential function or more than one function of RctB. Indeed, crtS modulates two kinds of RctB binding to the origin of Chr2, ori2, both of which we find to be Lrp-dependent. Some point mutants of RctB that are optimally modulated for ori2 binding without crtS still remained responsive to crtS and Lrp for replication enhancement. We infer that crtS-Lrp functions as a unit, which has an overarching role, beyond controlling initiator binding to ori2.
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Affiliation(s)
- Alexander Doan
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Soniya Chatterjee
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Roopa Kothapalli
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zaki Khan
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shaanit Sen
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Noemi Kedei
- Collaborative Protein Technology Resource, OSTP, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Jyoti K Jha
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dhruba K Chattoraj
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Revathy Ramachandran
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- College of Medicine, Mohammed Bin Rashid University, Dubai, UAE
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Niault T, Czarnecki J, Lambérioux M, Mazel D, Val ME. Cell cycle-coordinated maintenance of the Vibrio bipartite genome. EcoSal Plus 2023; 11:eesp00082022. [PMID: 38277776 PMCID: PMC10729929 DOI: 10.1128/ecosalplus.esp-0008-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
To preserve the integrity of their genome, bacteria rely on several genome maintenance mechanisms that are co-ordinated with the cell cycle. All members of the Vibrio family have a bipartite genome consisting of a primary chromosome (Chr1) homologous to the single chromosome of other bacteria such as Escherichia coli and a secondary chromosome (Chr2) acquired by a common ancestor as a plasmid. In this review, we present our current understanding of genome maintenance in Vibrio cholerae, which is the best-studied model for bacteria with multi-partite genomes. After a brief overview on the diversity of Vibrio genomic architecture, we describe the specific, common, and co-ordinated mechanisms that control the replication and segregation of the two chromosomes of V. cholerae. Particular attention is given to the unique checkpoint mechanism that synchronizes Chr1 and Chr2 replication.
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Affiliation(s)
- Théophile Niault
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
- Collège Doctoral, Sorbonne Université, Paris, France
| | - Jakub Czarnecki
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
| | - Morgan Lambérioux
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
- Collège Doctoral, Sorbonne Université, Paris, France
| | - Didier Mazel
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
| | - Marie-Eve Val
- Bacterial Genome Plasticity Unit, CNRS UMR3525, Institut Pasteur, Université Paris Cité, Paris, France
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