Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

DNA methylation is essential for genomic function and transposable element silencing. In plants, DNA methylation occurs in CG, CHG, and CHH contexts (where H = A, T, or C), with the maintenance of CG methylation mediated by the DNA methyltransferase MET1. The molecular mechanism by which MET1 maintains CG methylation, however, remains unclear. Here, we report cryogenic electron microscopy structures of Arabidopsis thaliana MET1. We find that the methyltransferase domain of MET1 specifically methylates hemimethylated DNA in vitro. The structure of MET1 bound to hemimethylated DNA reveals the activation mechanism of MET1 resembling that of mammalian DNMT1. Curiously, the structure of apo-MET1 shows an autoinhibitory state distinct from that of DNMT1, where the RFTS2 domain and the connecting linker inhibit DNA binding. The autoinhibition of MET1 is relieved upon binding of a potential activator, ubiquitinated histone H3. Taken together, our structural analysis demonstrates both conserved and distinct molecular mechanisms regulating CG maintenance methylation in plant and animal DNA methyltransferases.

DOI： 10.1038/s41467-025-63765-9

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Other Link： https://www.nature.com/articles/s41467-025-63765-9

Publisher：Research Square Platform LLC  

Abstract

Polycomb Repressive Complex 2 (PRC2) recognizes Polycomb response elements (PREs) and catalyzes trimethylation of histone H3 on lysine 27 (H3K27me3) for gene silencing. This silencing is counteracted by H3K36 methylation for epigenetic activation of gene expression. Here, we show that the Arabidopsis thaliana H3K36 methyltransferases SET DOMAIN-CONTAINING PROTEIN 7 (SDG7) and SDG8 antagonize PRC2-mediated silencing and establish H3K36 methylation patterns with the general transcription machinery. The sdg7 sdg8 double mutant shows developmental defects and lower H3K36me2 and H3K36me3 levels. SDG7 preferentially binds near PREs, but SDG8 is recruited to H3K36 methylation peaks. The sdg7 sdg8 phenotypes are partially rescued by loss of Polycomb function. SDG7 overlaps with PRC2 and its recruiters on chromatin and evicts them from shared target genes when conditionally induced. SDG8 and RNA Polymerase II associate at SDG- and RNA POLYMERASE II ASSOCIATED FACTOR 1 complex-regulated targets for H3K36 methylation and transcription. These results suggest that SDG proteins evict PRC2 from PREs to prevent H3K27me3 deposition and activate target genes via transcription-coupled H3K36 methylation.

DOI： 10.7554/eLife.100905.1

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Other Link： https://www.researchsquare.com/article/rs-3988955/v1.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Acetic acid is a simple and universal compound found in various organisms. Recently, acetic acid was found to play an essential role in conferring tolerance to water deficit stress in plants. This novel mechanism of drought stress tolerance mediated by acetic acid via networks involving phytohormones, genes, and chromatin regulation has great potential for solving the global food crisis and preventing desertification caused by global warming. We highlight the functions of acetic acid in conferring tolerance to water deficit stress.

DOI： 10.1007/s44154-023-00094-1

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Other Link： https://link.springer.com/article/10.1007/s44154-023-00094-1/fulltext.html

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (invited, special)  

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Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Type：Citizen’s meeting/Assembly

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Type：Citizen’s meeting/Assembly

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Type：Lecture

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Type：Citizen’s meeting/Assembly

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