Fusarium BP1 is a reader of H3K27 methylation

Area of Science:

• Molecular Biology
• Epigenetics
• Mycology

Background:

• Histone H3 lysine 27 methylation (H3K27me3) is a conserved epigenetic mark that represses gene transcription.
• The molecular mechanisms for recognizing H3K27me3 are not fully understood, particularly in fungal species.

Purpose of the Study:

• To identify and characterize H3K27me3 reader proteins in the fungal pathogen Fusarium graminearum.
• To elucidate the role of H3K27me3 recognition in gene regulation and fungal development.

Main Methods:

• Protein-protein interaction assays (e.g., co-immunoprecipitation) to identify BP1 interacting partners.
• Chromatin immunoprecipitation followed by sequencing (ChIP-seq) to determine genomic distribution of BP1 and H3K27me3.
• Phenotypic analysis of BP1 deletion mutants in terms of fungal growth, virulence, and secondary metabolite production.
• Phylogenetic analysis of BP1 orthologs across fungal species.

Main Results:

• Identified BAH-PHD protein 1 (BP1) as a direct H3K27me3 reader in Fusarium graminearum.
• BP1 interacts with the PRC2 component Suz12 and binds methylated H3K27 peptides.
• BP1 localizes to H3K27me3-marked regions and co-represses transcription.
• BP1 deletion mutants exhibit phenotypes similar to those lacking the H3K27 methyltransferase Kmt6.
• BP1's PHD finger binds DNA, potentially enhancing transcriptional repression.

Conclusions:

• BP1 is a key H3K27me3 reader in fungi, mediating transcriptional repression.
• The fungal H3K27me3 recognition mechanism involving BP1 is distinct from plant and mammalian systems.
• BP1 plays a significant role in regulating fungal gene expression, development, and virulence.