title: The role of MatP, ZapA and ZapB in chromosomal organization and dynamics in Escherichia coli.
abstract: Despite extensive research over several decades, a comprehensive view of how the Escherichia coli chromosome is organized within the nucleoid, and how two daughter chromosomes segregate has yet to emerge. Here we investigate the role of the MatP, ZapA and ZapB proteins in organizing the replication terminus (Ter) region and in the chromosomal segregation process. Quantitative image analysis of the fluorescently labeled Ter region shows that the replication terminus attaches to the divisome in a single segment along the perimeter of the cell in a MatP, ZapA and ZapB-dependent manner. The attachment does not significantly affect the bulk chromosome segregation in slow growth conditions. With or without the attachment, two chromosomal masses separate from each other at a speed comparable to the cell growth. The separation starts even before the replication terminus region positions itself at the center of the nucleoid. Modeling of the segregation based on conformational entropy correctly predicts the positioning of the replication terminus region within the nucleoid. However, the model produces a distinctly different chromosomal density distribution than the experiment, indicating that the conformational entropy plays a limited role in segregating the chromosomes in the late stages of replication.
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840, USA.
authors.forename: Jaana
authors.initials: J
authors.lastname: Männik
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996-1200, USA.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Castillo
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996-1200, USA.
authors.forename: Da
authors.initials: D
authors.lastname: Yang
authors.affiliation: Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996-1200, USA.
authors.forename: George
authors.initials: G
authors.lastname: Siopsis
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840, USA Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996-1200, USA JMannik@utk.edu.
authors.forename: Jaan
authors.initials: J
authors.lastname: Männik
mesh_terms: D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism; D002876:Chromosomes, Bacterial / Q000235:genetics* / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D056004:Molecular Dynamics Simulation; D018741:Replication Origin / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D008164:Luminescent Proteins; C533037:MatP protein, E coli; C520744:ZapA protein, E coli; C553097:ZapB protein, E coli