Linker proteins and epigenome regulation 

Having identified a role for linker histone variants (H1) in photomorphogenesis-associated epigenome dynamics, this project aims at assessing the role played by H1 at specific loci in the regulation of genome topology and epigenome dynamics. 

A previous study led by Gianluca Teano, PhD student in the lab, reported that Arabidopsis H1 occupies Polycomb Repressive Complex 2 (PRC2) target genes where it favors chromatin condensation and deposition of a specific histone mark, H3K27me3. It further unraveled a mechanistic framework by which, contrasting with its evolutionarily-conserved role, in plants H1 hinders PRC2 activity at gigantic interstitial telomeric regions (ITRs) located nearby the centromeres, thereby contributing to safeguard nucleus architecture and potentially also epigenome homeostasis (Teano et al., 2023).

Through collaborative studies with the Quadrana (IPS2, France) and the Amiard/Probst (GRED, France) labs, we now aim at determining:

• The functional relationships between H1 and Telomeric Repeat Binding (TRB) proteins, an H1-related protein family that mediates the recruitment of histone modifiers at telomeric sequences

• The regulatory role of H1-TRB protein interplay with PRC2 on plant development

• How abundant ITRs are generated and accommodated by plant genome and epigenome function.

Combining genomics, biochemistry, cytogenetics and population genetics, this project seeks to provide original knowledge on the mechanisms linking genome and epigenome organization.