Chromatin dynamic and mobility

This project focuses on developing tools that can be used in microscopy to study the position and expression of genes and chromatin moobility. To this end, we have adapted the ANCHOR system (NeoVirTech®) in plants to monitor the position (and displacement) of a single locus in the genome, directly in planta, in real-time (Meschichi et al., 2021). Coupled with the MCP-MS2 tool (Hani et al., 2021), which enables transcriptional activity to be monitored in real-time, or Single-molecule RNA-FISH (to detect single RNA), we can observe the transcriptional regulation of alleles in planta, using their 3D distribution in the nucleus as a variable. Changes in chromatin mobility, gene positioning and gene expression are then used as output to identifiy in Arabidopsis thaliana mutants the factors implicated in gene transcriptional regulation with an allelic and single-cell resolution.

Current projects:

1. 1. ANCHOR collection

Creation of a collection of A. thaliana lines with a variable genomic position of the ANCHOR system to make them visible by confocal microscopy directly in planta.

Staff involved: Aurore Sureau (CNRS IE CDD) and Frédéric Pontvianne (CNRS DR2)

Collaborators: Mathieu Ingouff (IRD, Montpellier) and Mathilde Grelon (INRAe, Versailles)

Funding : ANR DYSCORD (ANR-23-CE20-0036-03; 2023-2027)

2. 2. Real-time imaging of a transposable Elements (ONSEN)

We are developing innovative microscopy methodologies to monitor the entire life-cycle of the retro-transposable element ONSEN, activate under heat stress,  to explore its dynamic with a single-cell resolution. Our system is also able to detect Extra-chromosomal circular DNA (EccDNA) generated upon ONSEN activation and accumulate in the cell.

Staff involved: Petra Barnas (MSCA-DN PhD student 2026-2029), Aurore Sureau (CNRS IE CDD), Myrtille Barrot (PhD student 2025-28), Franziska Buslaps (European Project Manager, CNRS IE CDD)

and Frédéric Pontvianne (CNRS DR2)

Collaborators: Mathieu Ingouff (IRD, Montpellier) and Marie Mirouze (IRD, LGDP, Perpignan)

Funding : MSCA-DN AGILE (Grant Agreement No. 101226536; 2026-2030)

3. 3. Characterisation of the chromatin of tumor-liked cells induced after wild-type A. tumefaciens infections

We are using our microscopy methods to monitor the localisation and activity of T-DNA once injected into root cells by Agrobacterium tumefaciens. We are working with wild and virulent strains that induce tumour-like formation in numerous plant species in natura, here using A. thaliana as a study model.

Staff involved: Myrtille Barrot (PhD student 2025-28) and Frédéric Pontvianne (DR2 CNRS)

Collaborators: Denis Faure and Angélique Délèris (I2BC, Saclay)

Fundings: ANR Mobil-DNA (ANR-24-CE20-6240-03; 2024-2028) and Co-financing of EUR TULIP thesis for Myrtille Barrot