Granata J et al., PNAS - In mESCs and defined in vitro assays, EPOP and MTF2 stimulate PRC2 methyltransferase activity and promote de novo H3K27me3 deposition with GA- or GCN-rich DNA preference.

Study Highlights:
The study used mouse embryonic stem cells with an EED-rescue system and recombinant in vitro assays including HMT assays, EMSA, and ChIP-seq to probe EPOP and MTF2 function. Biochemical HMT assays on oligonucleosomes and dinucleosomes show both EPOP and MTF2 directly stimulate PRC2 catalytic activity, with MTF2 preferentially enhancing activity and binding on GCN-rich linkers and EPOP on GA-rich linkers. ChIP-seq during EED rescue demonstrated that EPOP is dispensable for initial PRC2 recruitment but its knockout reduces de novo H3K27me3 deposition by ~50% and cooperates with MTF2 and JARID2. Together these data indicate linker DNA sequence within nucleation sites guides subcomplex-specific PRC2 binding and catalytic output, influencing spatial establishment of H3K27me3 domains.

Conclusion:
EPOP and MTF2 define distinct PRC2 subcomplexes that stimulate PRC2 catalytic activity in a chromatin-dependent, DNA-sequence-specific manner to direct de novo H3K27me3 deposition.

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Reference:
Granata J., Liu S., Popoca L., Oksuz O., Reinberg D. EPOP and MTF2 activate PRC2 activity through DNA-sequence specificity. Proc. Natl. Acad. Sci. U.S.A. 2026;123:e2527303123. https://doi.org/10.1073/pnas.2527303123

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/

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