The Arabidopsis H3K27me3 demethylase JUMONJI 13 is a temperature and photoperiod dependent flowering repressor

Abstract

In plants, flowering time is controlled by environmental signals such as day-length and temperature, which regulate the floral pathway integrators, including FLOWERING LOCUS T (FT), by genetic and epigenetic mechanisms. Here, we identify an H3K27me3 demethylase, JUMONJI 13 (JMJ13), which regulates flowering time in Arabidopsis. Structural characterization of the JMJ13 catalytic domain in complex with its substrate peptide reveals that H3K27me3 is specifically recognized through hydrogen bonding and hydrophobic interactions. Under short-day conditions, the jmj13 mutant flowers early and has increased FT expression at high temperatures, but not at low temperatures. In contrast, jmj13 flowers early in long-day conditions regardless of temperature. Long-day condition and higher temperature induce the expression of JMJ13 and increase accumulation of JMJ13. Together, our data suggest that the H3K27me3 demethylase JMJ13 acts as a temperature- and photoperiod-dependent flowering repressor.

Crystal structures of REF6 and its complex with DNA reveal diverse recognition mechanisms

“…Both Relative of Early Flowering 6 (REF6) 6 and Early Flowering 6 (ELF6) 7 have been shown to be specific H3K27me3/2 demethylases in plants. JMJ13 is also an H3K27me3 site-specific demethylase, but has no significant activity on H3K27me2 8 . REF6, ELF6 and JMJ13 are homologous and belong to the KDM4 subfamily.…”

Histone Demethylases as Counterbalance to H3K27me3 Silencing in Plants

“…We have discussed that one of the main functions of H3K27 demethylases is to modulate gene expression and to reactivate H3K27m3 Polycomb-repressed genes in response to external or internal plant stimuli (Figure 2A iScience Review wildtype plants is reduced in epigenomic analyses of elf6 (Antunez-Sanchez and Gutierrez-Marcos, 2020) and it is much less prominent in jmj13 mutants (Zheng et al, 2019). Consistent with the partial functional redundancy among these proteins, H3K27me3 genomic analyses in the elf6 ref6 jmj13 triple mutant show an increased number of hypermethylated regions and misregulated genes compared to any single mutant (Yan et al, 2018).…”

Chromatin Dynamics and Transcriptional Control of Circadian Rhythms in Arabidopsis

“…The study shows that JMJ13, which possesses H3K27me3 site-specific demethylase activity, acts as a flowering repressor, and modulates flowering time in a photoperiod- and temperature-dependent manner [ 87 ]. The study also shows that the expression of main clock genes such as LHY and CCA1 and flowering-related genes such as CO was up-regulated in jmj13 mutant plants [ 87 ]. These results open the question of whether JMJ13 directly regulates clock through changes in histone demethylation at their loci.…”