Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle

Abstract Chromosome replication in Escherichia coli is primarily regulated at the initiation stage, where the DnaA protein activates replication at the chromosomal origin, oriC. Both DnaA and oriC undergo feedback regulation based on replication progression. Previously, we reconstituted the entire r...

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Main Authors: Koki Kanoh, Masayuki Su’etsugu
Format: Article
Language:English
Published: Nature Portfolio 2025-02-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-88988-0
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author Koki Kanoh
Masayuki Su’etsugu
author_facet Koki Kanoh
Masayuki Su’etsugu
author_sort Koki Kanoh
collection DOAJ
description Abstract Chromosome replication in Escherichia coli is primarily regulated at the initiation stage, where the DnaA protein activates replication at the chromosomal origin, oriC. Both DnaA and oriC undergo feedback regulation based on replication progression. Previously, we reconstituted the entire replication cycle using 26 purified proteins in a system termed replication cycle reaction (RCR). This system enables the exponential propagation of oriC circular DNA through autonomous replication cycles. In this study, we integrated regulatory mechanisms into the RCR and analyzed their effects on DNA propagation using real-time detection. The oriC sequestration system involves SeqA binding to hemimethylated oriC—generated during nascent DNA synthesis to prevent reinitiation. SeqA inhibited RCR, but the addition of Dam methylase relieved this inhibition. In the DnaA regulation system, active ATP-DnaA is inactivated by Hda in association with the DNA-loaded clamp, converting it to ADP-DnaA. Reactivation occurs through nucleotide exchange facilitated by the DnaA-reactivating sequence (DARS). Hda suppressed replication in RCR, while DARS restored activity. These results demonstrate that regulatory mechanisms controlling replication initiation in the RCR system faithfully replicate the cell cycle regulation of chromosome replication observed in vivo.
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spelling doaj-art-fb77e8f8e3eb408ca7bcc88064a844282025-02-09T12:35:31ZengNature PortfolioScientific Reports2045-23222025-02-0115111010.1038/s41598-025-88988-0Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycleKoki Kanoh0Masayuki Su’etsugu1Department of Life Science, College of Science, Rikkyo UniversityDepartment of Life Science, College of Science, Rikkyo UniversityAbstract Chromosome replication in Escherichia coli is primarily regulated at the initiation stage, where the DnaA protein activates replication at the chromosomal origin, oriC. Both DnaA and oriC undergo feedback regulation based on replication progression. Previously, we reconstituted the entire replication cycle using 26 purified proteins in a system termed replication cycle reaction (RCR). This system enables the exponential propagation of oriC circular DNA through autonomous replication cycles. In this study, we integrated regulatory mechanisms into the RCR and analyzed their effects on DNA propagation using real-time detection. The oriC sequestration system involves SeqA binding to hemimethylated oriC—generated during nascent DNA synthesis to prevent reinitiation. SeqA inhibited RCR, but the addition of Dam methylase relieved this inhibition. In the DnaA regulation system, active ATP-DnaA is inactivated by Hda in association with the DNA-loaded clamp, converting it to ADP-DnaA. Reactivation occurs through nucleotide exchange facilitated by the DnaA-reactivating sequence (DARS). Hda suppressed replication in RCR, while DARS restored activity. These results demonstrate that regulatory mechanisms controlling replication initiation in the RCR system faithfully replicate the cell cycle regulation of chromosome replication observed in vivo.https://doi.org/10.1038/s41598-025-88988-0DNA amplificationChromosome replicationRegulation of replication initiation
spellingShingle Koki Kanoh
Masayuki Su’etsugu
Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle
Scientific Reports
DNA amplification
Chromosome replication
Regulation of replication initiation
title Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle
title_full Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle
title_fullStr Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle
title_full_unstemmed Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle
title_short Real-time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle
title_sort real time analysis of initiation regulation systems during the progression of the reconstituted chromosomal replication cycle
topic DNA amplification
Chromosome replication
Regulation of replication initiation
url https://doi.org/10.1038/s41598-025-88988-0
work_keys_str_mv AT kokikanoh realtimeanalysisofinitiationregulationsystemsduringtheprogressionofthereconstitutedchromosomalreplicationcycle
AT masayukisuetsugu realtimeanalysisofinitiationregulationsystemsduringtheprogressionofthereconstitutedchromosomalreplicationcycle