Post-replicative pairing of sister chromosomes in Escherichia coli involves multiple activities of the MatP protein

Estelle Crozat, Catherine Tardin, Maya Salhi, Philippe Rousseau, Armand Lablaine, Tommaso Bertoni, David Holcman, Bianca Sclavi, Pietro Cicuta, and François Cornet

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Oct 02, 2019
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Received Date: 23rd September 19

Regions of the chromosome where replication terminates host specific activities in all organisms. In Escherichia coli, this region, named ter, is also the last segregated before cell division. Delayed segregation is controlled by the MatP protein, binding specific matS sites along ter. We investigated the fate of the E. coli ter region and the role of MatP by combining a detailed in vivo analysis of the mobility of a ter locus at short time scales with in vitro biochemical approaches. We found that ter dynamics differs only slightly from that of a control locus located close to the replication origin, except when sister ter loci are paired following their replication. MatP thus mainly acts in maintaining sister ter paired, but only plays a faint role in absence of pairing. This effect depends on MatP, its 20 C-terminal residues and ZapB to different levels, implying a role for all known MatP activities. We characterised MatP/DNA complexes and conclude that while MatP binds DNA as a tetramer, it barely forms specific DNA loops by bridging matS sites in a DNA rich environment. We propose that tetramerisation of MatP links matS sites with ZapB and/or with non-specific DNA to promote optimal pairing of sister ter regions until cell division.

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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

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