JMJ Histone Demethylases Balance H3K27me3 and H3K4me3 Levels at the <i>HSP21</i> Locus during Heat Acclimation in <i>Arabidopsis</i>

• Main Authors: Nobutoshi Yamaguchi, Toshiro Ito
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Biomolecules
• Subjects: <i>Arabidopsis thaliana</i>; Jumonji; heat acclimation; heat shock protein 21; H3K4me3; H3K27me3
• Online Access: https://www.mdpi.com/2218-273X/11/6/852

Exposure to moderately high temperature enables plants to acquire thermotolerance to high temperatures that might otherwise be lethal. In <i>Arabidopsis thaliana</i>, histone H3 lysine 27 trimethylation (H3K27me3) at the <i>heat shock protein 17.6C</i> (<i>HSP17.6C</i>) and <i>HSP22</i> loci is removed by Jumonji C domain-containing protein (JMJ) histone demethylases, thus allowing the plant to ‘remember’ the heat experience. Other heat memory genes, such as <i>HSP21,</i> are downregulated in acclimatized <i>jmj</i> quadruple mutants compared to the wild type, but how those genes are regulated remains uncharacterized. Here, we show that histone H3 lysine 4 trimethylation (H3K4me3) at <i>HSP21</i> was maintained at high levels for at least three days in response to heat. This heat-dependent H3K4me3 accumulation was compromised in the acclimatized <i>jmj</i> quadruple mutant as compared to the acclimatized wild type. JMJ30 directly bound to the <i>HSP21</i> locus in response to heat and coordinated H3K27me3 and H3K4me3 levels under standard and fluctuating conditions. Our results suggest that JMJs mediate the balance between H3K27me3 and H3K4me3 at the <i>HSP21</i> locus through proper maintenance of H3K27me3 removal during heat acclimation.