Typologie d'actualités: Team Chemistry, Imaging and Exobiology
Contrast agents to combine 1H and 19F MRI

Today, magnetic resonance imaging (MRI) is based on the detection of water protons (1H) in tissues. MRI of 19F fluorine offers complementary advantages, but its use is hampered by a lack of suitable imaging agents, soluble in water and easily detectable. In order to improve the sensitivity of detecting 19F MRI signals, a CBM team used Mn2+ ions to form complexes with small fluorinated molecules. Unlike currently used nanoparticles, these small molecular probes have well-defined chemical structures and better biocompatibility and water solubility. Finally, thanks to the paramagnetism of manganese(II), they generate a strong signal in MRI. In addition, these fluorinated contrast agents are also active in proton MRI, allowing proton and fluorine MRI images to be superimposed for precise anatomical mapping.
This advance, published in Angewandte Chemie International Edition, opens new horizons in fluorine MRI. It was reported by CNRS Chimie on its website.
Reference :
Small, Fluorinated Mn2+ Chelate as an Efficient 1H and 19F MRI Probe
Éva Tóth, Zoltán Garda, Frédéric Szeremeta, Océane Quin, Enikő Molnár, Balázs Váradi, Rudy Clémençon, Sandra Même, Chantal Pichon and Gyula Tircsó
Angewandte Chemie International Edition, 2024
DOI: 10.1002/anie.202410998
2024, September 27 – Nicolas GIRAUD seminar

2024, August 30 – Zoltan GARDA seminar
July 19, 2024 – Thibault Fillion’s thesis defense

Protein filaments in the regulation of gene expression

Although every cell in our body contains the same genetic information, cells differ in the way they use it, a process known as “gene expression”. The regulation of gene expression is orchestrated by proteins called transcription factors, which bind to specific sequences within DNA. Transcription factors are traditionally thought to operate mainly as single molecules or dimers.
The article by Mance et al. reveals that several transcription factors of the family known as ZBTB, present in humans and other animals, have the capacity to form non-covalent filamentous structures composed of numerous identical copies of proteins arranged in a chain. At the molecular level, such structures could offer significant advantages for binding to DNA, which is itself an elongated molecule containing numerous repeated sequences. A few examples of filament-forming transcription factors had already been reported, but this study extends the concept to a large family of this protein with important functions. The study - which combines structural, biophysical and functional analysis carried out in vitro and in cells - was carried out by the "Post-translational modifications and DNA repair" team at the CBM and their collaborators in Orléans, Rennes and Marseille, including the "Functional mass spectrometry of molecular assemblies" team also at the CBM.
The findings from this research, together with a complementary study by groups of Benjamin Ebert and Eric Fischer from Dana-Farber Cancer Institute at Harvard (published back-to-back in the same issue of Molecular Cell), challenge the traditional view of transcription factor functionality.
In cells, ZBTB proteins are regulated through a process called SUMOylation, where a small tag called SUMO is added to them, changing how they function. Studies on ZBTB proteins undertaken in Orléans, during which the filamentous structures were discovered, are part of the "SUMOwriteNread" project funded by the European Union (ERC grant no 101078837). Researchers are currently investigating the interplay between the ability to form filaments and SUMO tagging to understand the complex reality of gene expression regulation.
This research was reported by CNRS Chimie on its website.
Dynamic BTB-domain filaments promote clustering of ZBTB proteins.
Lucija Mance, Nicolas Bigot, Edison Zhamungui Sánchez, Franck Coste, Natalia Martín-González, Siham Zentout, Marin Biliškov, Zofia Pukało, Aanchal Mishra, Catherine Chapuis, Ana-Andreea Arteni, Axelle Lateur, Stéphane Goffinont, Virginie Gaudon, Ibtissam Talhaoui, Ignacio Casuso, Martine Beaufour, Norbert Garnier, Franck Artzner, Martine Cadene, Sébastien Huet, Bertrand Castaing & Marcin Józef Suskiewicz
Molecular Cell 2024
https://doi.org/10.1016/j.molcel.2024.05.029
CNRS Chimie Emergence@International

Federico Perche, a researcher in the "MACS : Molecular Assemblies and Complex Systems" team, has been awarded CNRS Chimie Emergence@International.
He will be going to the United States to develop research collaborations in his field of mRNA and siRNA delivery.
During a 2-week stay, he will visit the Universities of San Diego (Pr Kwon and Pr Shresta, Arizona (Dr Liu), Texas A&M (Dr Zhu) and Chicago (Dr Voth).
Federico has started a collaboration with Dr Shresta on mRNA vaccination and is looking to develop new collaborations.