Decoding the histone H3.1 variant and its role in epigenetic signalling

Le June 27 2025 at 11h00 Séminaire

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Abstract: Histone proteins play a critical role in packaging genomic DNA and epigenetic signaling. Since their initial characterization five decades ago, several histone variants have been identified and shown to play a vital role in various DNA-based transactions. For example, in contrast to histone H3.1 (canonical), histone H3.3 (variant) is deposited on chromatin throughout the cell cycle and in non-dividing cells. However, these two histones share more than 95% of sequence identity. Differences between these histone H3 proteins include divergence in the regions recognized by dedicated chaperones and one amino acid on their N-terminal tails. Despite being nearly identical, both histone H3 proteins have been exquisitely conserved across evolution. I will present our results stemming from our efforts to determine the structural underpinnings underlying the recognition and methylation of histone H3.1 by a novel histone reader and a dedicated SET domain lysine methyltransferase, respectively. Collectively, our findings suggest that histone H3.1 is vital for the mitotic inheritance of a heterochromatic mark during DNA replication and pivotal for DNA damage repair.