COOLAIR and PRC2 function in parallel to silence FLC during vernalization
Mathias Nielsen1, Govind Menon2, Yusheng Zhao1
1Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
Summary
Antisense transcription (COOLAIR) and Polycomb Repressive Complex 2 (PRC2) work together to silence the FLOWERING LOCUS C (FLC) gene in Arabidopsis, responding to cold temperatures for robust epigenetic regulation.
Area of Science:
- Plant molecular biology
- Epigenetics
- Gene regulation
Background:
- Noncoding transcription influences chromatin structure and environmental responses.
- The precise mechanisms linking antisense transcription, Polycomb Repressive Complex 2 (PRC2), and epigenetic silencing remain incompletely understood.
Purpose of the Study:
- To investigate the interplay between antisense transcription (COOLAIR) and PRC2 in the winter-induced epigenetic silencing of Arabidopsis FLOWERING LOCUS C (FLC).
- To elucidate the molecular mechanisms underlying FLC repression by defining the dynamics and regulation of these pathways.
Main Methods:
- Genetic analysis of Arabidopsis lines with altered antisense pathway activity.
- Chromatin analyses to assess epigenetic states.
- Computational modeling to define regulatory mechanisms.
Main Results:
- FLC is silenced via two parallel pathways: a rapid COOLAIR transcription-mediated response and a slower PRC2-dependent epigenetic maintenance mechanism.
- Both COOLAIR and PRC2 pathways are co-regulated by NTL8, a transcriptional regulator whose accumulation is linked to reduced dilution during slow growth at low temperatures.
Conclusions:
- The combined action of fast-acting COOLAIR and slow-switching PRC2, regulated by temperature-dependent growth dynamics, provides a flexible yet robust system for epigenetic silencing of FLC in response to fluctuating environmental temperatures.
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