Research interests

Since my recruitment as a CNRS researcher in 2008, I focus on the role of chromatin organization in gene expression control. We study histone variant dynamics and the role of histone chaperones in controlling deposition and turnover of histone proteins.

Key Findings

• Replication-independent deposition of the histone variant H3.3 by the histone chaperone HISTONE REGULATOR A (HIRA) in Arabidopsis is required for the maintenance of nucleosome occupancy (Duc, 2015; Layat, 2021).

• HIRA and the Arabidopsis orthologue of Alpha Thalassemia-mental Retardation X-linked (ATRX) function in complementary pathways of histone H3.3 deposition and loss of ATRX alters the cellular H3.1/H3.3 balance in the cell (Duc, 2017).

• Replication-coupled histone assembly mediated by CHROMATIN ASSEMBLY FACTOR 1 (CAF-1) promotes enrichment in histone variants H3.1 and H2A.W, and the repressive histone modification H3K9me2 at pericentromeric repeats as well as their organization into chromocenters during post-germination development. This work revealed the importance of nucleosome composition in higher-order chromatin organization (Benoit, 2019).

• NUCLEAR AUTOANTIGENIC SPERM PROTEIN (NASP) is required for accurate deposition and maintenance of the centromeric H3 variant, CenH3, in Arabidopsis identifying NASP as the first histone chaperone protein required for the handling of the plant CenH3 (Le Goff, 2021).

• Imbibition triggers a broad, replication-independent eviction of the seed-enriched histone variants H2B.8 and H3.3, revealing chromatin reprogramming during the developmental transition from seed-to-seedling (Simon, 2025).

Currently, we are using genetics, biochemistry, epigenomics and microscopy and focus on three major topics:

The developmental transition from seed to seedling

We are examining how nucleosome composition and higher-order chromatin organization change during the developmental transition from seed to seedling, and how these chromatin changes interplay with transcriptional reprogramming. Our recent work showed that seed germination triggers a broad, replication-independent eviction of the seed-enriched histone variants H2B.8 and H3.3 (ANR project SeedChrom).

Seed priming

Seed priming (pre-sowing seed treatment) is widely applied to improve seed vigor, germination and yield. However, the chromatin changes associated with priming and whether seed priming involves epigenetic memory, remain poorly understood. Within the framework of the MSCA DN EpiSeedlink project, we study the chromatin changes induced by seed priming in Brassica napus. We aim to identify mechanisms that could support the development of adaptive and sustainable priming strategies (EU MSCA DN EpiSeedLink, CAP20-25).

Functional diversification of H2A variants

Different histone H2A variants have emerged during the evolution of photosynthetic organisms, exemplified by H2A variants specific to brown algae. As a partner of the ANR project His2AVar, we study the role of these novel H2A variants in genome organization and gene expression, and their capacity to functionally complement the loss of H2A orthologs in distant algae or angiosperms (ANR project His2AVar).

Funding

 
We acknowledge funding by the ANR (ongoing grants 4D-Heat, SeedChrom and His2AVar), from the MSCA Doctoral network EpiSeedLink, the I-site CAP20-25 as well as networking support from the PHCs Barrande et Ulysse.

For more information on the activities of Plant Epigenetics research groups in France, please visit the website of the GDR EPIPLANT.

Collaborations

1. Bailly (IBPS), F. Barneche (IBPS, FR), M. Benhamed (IPS2, FR), C. Carles (LPCV, FR), M. Dvorackova (CEITEC, CZ), G. Farge (UCA, FR), U. Feuerstein (DSV, DE), K. Grasser (UREG, DE), S. Farrona (NUIG, IR), I. Lermontova (IPK, DE), C. Raynaud (IPS2, FR), V. Rubio (CNB, SP), L. Quadrana (IPS2, FR).