Biology subjects

Montez, M.

Publications and source records attributed to Montez, M..

3 recordsLinked to original sources

bioRxiv2026

Vernalisation-induced changes to the Arabidopsis circadian clock require Polycomb Repressive Complex 2 and are FLC-independent

In many plants, prolonged winter cold and seasonal day-length changes align the transition to flowering with spring. This occurs through the vernalisation and photoperiod pathways, respectively. Despite roles for the circadian clock in regulating both pathways, their mechanisms have mainly been studied in isolation and their interactions are not fully understood. We found that vernalisation elicits changes in the circadian clock and this is linked to alterations in several clock-controlled outputs, including photoperiodic flowering. Importantly, vernalisation-induced changes in specific clock genes are stable and persist upon return to warmth, providing the circadian clock with a memory of prior long-term cold exposure. The changes are not systematic and affect specific circadian oscillator genes. This change requires the epigenetic regulator Polycomb Repressive Complex 2 (PRC2), but not the major genetic determinants of vernalisation FRIGIDA (FRI) and FLOWERING LOCUS C (FLC). In contrast to their role in FLC silencing, core PRC2 components but not accessory proteins are required for these changes in the clock post-vernalisation. Our work raises the possibility that long-term cold feeds epigenetic information into the clock as a seasonal response mechanism, potentially preparing plants for the coming season.

plant biology↗

bioRxiv2025

Chromatin retained MUSHER lncRNA integrates ABA and DOG1 signalling pathways to enhance Arabidopsis seeds dormancy.

Many plant lncRNAs regulate gene expression by binding to chromatin, but how they are retained at the target loci is unclear. We identify a new, chromatin-localized lncRNA - MUSHER, which activates two parallel regulatory pathways to increase Arabidopsis seed dormancy. MUSHER is upregulated in response to high temperatures, contributing to the induction of secondary dormancy. It promotes DOG1 expression by recruitment of the CPSF complex to enhance the proximal cleavage and polyadenylation at the DOG1 gene. It also increases ABA sensitivity in seeds by activating PIR1 gene transcription. These genes, located on different chromosomes, are both bound by MUSHER, despite lacking sequence homology. The chromatin association of MUSHER enables the integration of the DOG1-and ABA pathways to adjust seed germination timing. Additionally, MUSHER and other lncRNAs interact with U1 snRNP, which is required for their chromatin localisation, revealing a novel function of U1 snRNP in plants.

molecular biology↗

bioRxiv2025

Cold-induced nucleosome dynamics linked to silencing of Arabidopsis FLC

Temperature influences nucleosome dynamics, and thus chromatin, to regulate gene expression. Such mechanisms underlie the epigenetic silencing of Arabidopsis FLOWERING LOCUS C (FLC) by prolonged cold. Here, we show a temperature-dependent transition in local chromatin structure at the H3K27me3 nucleation region, from a modality active for transcription to a state that can be Polycomb silenced. In vivo chromatin measurements and coarse-grained simulations at near-atomistic resolution show the active transcription state is characterized by a highly dynamic nucleosome arrangement that exposes the FLC TSS. Cold exposure then changes the chromatin structure by reducing nucleosome dynamics and re-positioning the +1 nucleosome, leading to transcriptional repression. This local chromatin transition partially depends on VRN1, a non-sequence-specific DNA-binding protein. Loss of VRN1 results in hyperaccumulation of H2A.Z, more dynamic nucleosomes and an inability to accumulate H2Aub and H3K27me3. Our work highlights how local nucleosome dynamics link to chromatin structure transitions to integrate temperature inputs into epigenetic switching mechanisms in plants.

molecular biology↗