Different roles of two H3K36 methyltransferasesin transcriptional regulation and association with facultativeheterochromatin

This study is led by Professor Zeng Tao(Institute of Biotechnology, Zhejiang University, Hangzhou, China). The authors identified twoH3K36 methyltransferases, Ash1 and Set2, in Magnaportheoryzae, which causes the devastating worldwide rice blast disease. The authors firstlycreated single and double deletion strains and detected the level of H3K26me2/3. Subsequently, the authorsfurther depict the detailed occupancy of H3K26me2/3 in the deletion mutants by ChIP-seq. Combing with their transcriptomes, the authors analyzed their transcriptional regulation and association with facultativeheterochromatin.

Combined with methods of RNA-seq and ChIP-seq, the authors revealedthat both Ash1 and Set2 are redundantly required for the full H3K36me2/3 activity in M.oryzae. Moreover, Ash1 and Set2 distinguish genomicH3K36me2/3-marked regions and are differentially associated with repressed and activated transcriptionrespectively. Furthermore, Ash1-catalysedH3K36me2is co-localized with facultative heterochromatinH3K27me3 atthe chromatinand Ash1is required for the enrichment and transcriptional silencing of H3K27me3-occupied genes. With the different roles of Ash1 and Set2 in H3K36me2/3 enrichment and transcriptionalregulation on the stress-responsive genes, they differentially response to various stresses inM. oryzae.

Overall, the authors reveal a novel mechanism by which two H3K36 methyltransferases catalyzeH3K36me2/3 that differentially associate with transcriptional activities and contribute to enrichmentof facultative heterochromatin. In summary, these new insights in distribution patterns and transcriptionaleffects of H3K36me2/3 broaden our currentunderstanding of chromatin-based transcriptionin eukaryotes.

See the article:

Two H3K36 methyltransferases differentially associatewith transcriptional activity and enrichment of facultativeheterochromatin in rice blast fungus.

https://link.springer.com/article/10.1007/s42994-023-00127-3