Orateur
Description
Coordina3ng chromosome segrega3on with cell division is a key-step of the cell cycle for any bacteria. E. coli does not seem to require an ac3ve system to segregate its chromosomes. Instead, entropy and a specific organiza3on of the chromosome into domains seem to explain the observed choreography. MatP is the DNA-binding protein responsible for organizing the ter region by preven3ng the SMC proteins, MukBEF, to compact it. It also helps localizing the Z-ring at midcell, by interac3ng with ZapB, which interact in turn with ZapA and FtsZ, forming the so-called Ter-linkage. MatP also keeps the replicated ter regions at the septum un3l cell division.
First, we studied MatP and its ability to bind ter by following the short-term dynamics (20s) of fluorescent chromosomal loci in strains deleted for matP and/or zapB. We also used Tethered Par3cle Mo3on (TPM), as well as gel shiU assays to beVer characterize how MatP binds to DNA.
Taken together, these results revealed that tetramers of MatP very dynamically bridge the ter region of the chromosomes with the septum (i.e ZapB) before replica3on, and constrain their movements only at this point (Crozat et al, 2020).
We are now studying these mutants by fluorescent microscopy. Varying the amount of ZapB enables us to shed light on a peculiar mechanism ac3ng on chromosome segrega3on, and the precise role played by MatP at this stage of the cell cycle.
