Estelle Crozat-brendon

Estelle Crozat-brendon


MC UPS
05 61 33 59 16

Teams

Presentation

I am interested in the organisation and dynamics of bacterial chromosomes and the proteins involved in this process, especially the Nucleoid-Associated-Proteins (NAPs). Using a variety of tools (biochemistry, biophysics, genetics and microscopy), I am trying to understand the binding of proteins such as MatP, Fis, H-NS, and their effect on the structure of the chromosome in E. coli. To do this, I have been combining a biophysical method, the Tethered Particle Motion (TPM) set-up, with short-time microscopy, which allows to generate physical properties of chromosomal loci (MSD, Diffusion Coefficient…) by analysing the motion of foci in the cell in different conditions or mutants.

 

TPM set-up a. A bead is attached to a single DNA molecule (*).  When a protein binds (here, MatP binds matS sites), this induces a conformational change (**) or a loop (***), which reduces the apparent length of the DNA, and therefore the Brownian motion of the bead. b. Example of a trace for a bead linked to a DNA containing 2 matS. Several, short looping events can be observed, indicating the dynamics of the loop formation.

 

 

Example of a TPM set-up to study MatP
a. A bead is attached to a single DNA molecule (*).  When a protein binds (here, MatP binds matS sites), this induces a conformational change (**) or a loop (***), which reduces the apparent length of the DNA, and therefore the Brownian motion of the bead.
b. Example of a trace for a bead linked to a DNA containing 2 matS. Several, short looping events can be observed, indicating the dynamics of the loop formation.

In collaboration with Dr. Catherine Tardin (IPBS).

 

 

Example of a TPM set-up to study MatP

 

Example of chromosomal loci movement

A loci near the origin of replication has been tagged with a parS sequence, so that we can observe a focus formed by the fixation of ParB-GFP. We are then using Matlab  scripts to extract the trajectories of each focus, and their properties.

In collaboration with Prof. Pietro Cicuta, Cambridge University.

 

 

 

Institute

Université Paul Sabatier
118 Route de Narbonne

31062 TOULOUSE Cedex
France

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