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Updated: Mar 17, 2026

Investigating Interactions Between Histone Modifying Enzymes and Transcription Factors in vivo by Fluorescence Resonance Energy Transfer
Published on: October 14, 2022
Arabidopsis transcriptional repressor VAL1 triggers Polycomb silencing at FLC during vernalization
Julia I Qüesta1, Jie Song2, Nuno Geraldo1
1Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
Abstract:
The determinants that specify the genomic targets of Polycomb silencing complexes are still unclear. Polycomb silencing of Arabidopsis FLOWERING LOCUS C (FLC) accelerates flowering and involves a cold-dependent epigenetic switch. Here we identify a single point mutation at an intragenic nucleation site within FLC that prevents this epigenetic switch from taking place. The mutation blocks nucleation of plant homeodomain-Polycomb repressive complex 2 (PHD-PRC2) and indicates a role for the transcriptional repressor VAL1 in the silencing mechanism. VAL1 localizes to the nucleation region in vivo, promoting histone deacetylation and FLC transcriptional silencing, and interacts with components of the conserved apoptosis- and splicing-associated protein (ASAP) complex. Sequence-specific targeting of transcriptional repressors thus recruits the machinery for PHD-PRC2 nucleation and epigenetic silencing.
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