Dispensability of extrinsic DnaA regulators in Escherichia coli cell-cycle control

• 成果类型: Article
• 署名作者: Boesen, Thias Oberg; Charbon, Godefroid; Fu, Haochen; Jensen, Cara; Sandler, Michael; Jun, Suckjoon; Lobner-Olesen, Anders
• 署名单位: University of Copenhagen; University of California System; University of California San Diego
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9077
• DOI: 10.1073/pnas.2322772121
• 发表日期: 2024-08-13
• 关键词: replication initiation; chromosomal replication; atp hydrolysis; mediated inactivation; protein; gene; hda; origin; size; complex

摘要

Investigating a long-standing conceptual question in bacterial physiology, we examine why DnaA, the bacterial master replication initiator protein, exists in both ATP and ADP forms, despite only the ATP form being essential for initiation. We engineered the O4 Escherichia coli strain, devoid of all known external elements facilitating the DnaA-ATP/ADP conversion and found that these cells display nearly wild-type behaviors under nonoverlapping replication cycles. However, during rapid growth with overlapping cycles, O4 cells exhibit initiation instability. This aligns with our model predictions, suggesting that the intrinsic ATPase activity of DnaA alone is sufficient for robust initiation control in E. coli and the DnaA-ATP/ADP conversion regulatory elements extend the robustness to multifork replication, indicating an evolutionary adaptation. Moreover, our experiments revealed constant DnaA concentrations during steady-state cell elongation in both wild-type and O4 cells. These insights not only advance our understanding of bacterial cell-cycle regulation and DnaA but also highlight a fundamental divergence from eukaryotic cell-cycle controls, emphasizing oscillations in eukaryotes.