Coupling between DNA replication, segregation, and the onset of constriction in Escherichia coli
Sriram Tiruvadi-Krishnan,
Jaana Männik,
Prathitha Kar,
Jie Lin,
Ariel Amir,
Jaan Männik
Affiliations
Sriram Tiruvadi-Krishnan
Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
Jaana Männik
Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
Prathitha Kar
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02134, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02134, USA
Jie Lin
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02134, USA; Center for Quantitative Biology and Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
Ariel Amir
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02134, USA; Corresponding author
Jaan Männik
Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA; Corresponding author
Summary: Escherichia coli cell cycle features two critical cell-cycle checkpoints: initiation of replication and the onset of constriction. While the initiation of DNA replication has been extensively studied, it is less clear what triggers the onset of constriction and when exactly it occurs during the cell cycle. Here, using high-throughput fluorescence microscopy in microfluidic devices, we determine the timing for the onset of constriction relative to the replication cycle in different growth rates. Our single-cell data and modeling indicate that the initiation of constriction is coupled to replication-related processes in slow growth conditions. Furthermore, our data suggest that this coupling involves the mid-cell chromosome blocking the onset of constriction via some form of nucleoid occlusion occurring independently of SlmA and the Ter linkage proteins. This work highlights the coupling between replication and division cycles and brings up a new nucleoid mediated control mechanism in E. coli.
