Director de Recherche / Research director, CNRS
Equipe : Régulations épigénétiques de la transcription et des transposons
Team: Page en anglais de l'équipe
Laboratoire Génome et développement des plantes (LGDP)
Université de Perpignan Via Domitia, Campus Moulin-à-Vent
58 avenue Paul-Alduy, Bât. T, 66860 PERPIGNAN Cedex 9
Phone: +33(0)4 30 19 81 16
Email : frederic.pontvianne@univ-perp.fr
Axe gene dose and dosage
Lead: Frédéric Pontvianne
Staff involved: Nathalie Picault, Khadidiatou DIOP, Aurore Sureau, Myrtille Barrot
We aim to understand the mechanisms that regulate gene expression before transcription begins.
Transcription of a gene, or any other transcribed element, is only possible when the locus is accessible. In other words, it must be located in a region of the nucleus open to transcription factors and have an epigenetic signature compatible with transcriptional activity.
The three-dimensional organisation of the genome in the nucleus plays a key role in this regulation, as do chromatin modifications such as DNA methylation and post-translational histone modifications.
In our team, we are studying this regulation at the allelic level using genomic (CITRUS project) and microscopic (POSITIONING project) approaches.
CITRUS project :
Staff involved: Khadidiatou DIOP (PhD student 2022-25), Marie Bonnin (Post-doc 2024), Nathalie Picault and Frédéric Pontvianne
Collaborators: SEAPAG team (CIRAD, INRAe Montpellier, Corsica and Guadeloupe)
Funding: Occitanie Region and UPVD
- The aim of this project is to use the absence of a sexual barrier in citrus fruit to study and understand the origin of the differential allelic expression observed in cross-genus hybrids between Citrus reticulata (Clementine) and Microcitrus australasica (Caviar Lemon). The hybrid (Figure 1) produced by crossing these two species, which diverge by around 8 million years, makes it possible to use the large number of nucleotide modifications accumulated to determine the parental origin of each transcript. We are working on the effects of transcriptional dominance and trying to establish the role of epigenetic mechanisms in the establishment of this dominance.
POSITIONING project
This project focuses on developing tools that can be used in microscopy to study the position and expression of genes when there is no difference in the nucleotide sequence. To this end, we have adapted the ANCHOR system (NeoVirTech®) in plants to monitor the position of a single locus in the genome (Meschichi et al., 2021). With this system, we can monitor the position (and displacement) of a locus directly in planta in real-time (Figure 2). Coupled with the MCP-MS2 tool (Hani et al., 2021), which enables transcriptional activity to be monitored in real-time, we can observe the transcriptional regulation of alleles in planta, using their 3D distribution in the nucleus as a variable.
This project has several sub-projects:
- 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)
- Real-time imaging of allelic expression
We are developing innovative microscopy methodologies to characterise gene expression with allelic resolution in order to explore, in particular, intra- and inter-cell transcriptional variability, or the phenomenon of allelic clustering.
Staff involved: Aurore Sureau (CNRS IE CDD) and Frédéric Pontvianne (CNRS DR2)
Collaborators: Laurent Nussaume (CEA, Cadarache) and Stefanie Rosa (SLU, Sweden)
- 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 Rayan Oulhad (Master 2, University of Montpellier) and Frédéric Pontvianne (DR2 CNRS)
Collaborators: Denis Faure and Angélique Délèris (I2BC, Saclay)
Fundings: Co-financing of EUR TULIP thesis for Myrtille Barrot
ANR Mobil-DNA (ANR-24-CE20-6240-03; 2024-2028)