BioProject

Leaf senescence is governed by a complex regulatory network involving dynamic reprogramming of gene expression. More...

Leaf senescence is governed by a complex regulatory network involving dynamic reprogramming of gene expression. Recent evidence indicates that trimethylation of histone H3 at lysine 4 (H3K4me3) alters gene expression during leaf senescence. However, it is largely unknown how histone modification is regulated in an age-dependent manner. We found that JMJ16, an Arabidopsis JmjC-domain containing protein, is a specific H3K4 demethylase that negatively regulates leaf senescence. The histone demethylase activity and the JmjN, JmjC, and FYR domains of JMJ16, but not the zf-C5HC2 domain, are essential for JMJ16 function in the regulation of leaf senescence. Genome-wide analysis revealed a widespread coordinated up-regulation of H3K4me3 and gene expression associated with leaf senescence in the loss-of-function jmj16 mutant compared with the wild type. Genetic analysis indicated that JMJ16 negatively regulates leaf senescence at least partly through repressing the expression of WRKY53 and SAG201, two known positive regulators of leaf senescence. Further analyses demonstrated that JMJ16 associates with WRKY53 and SAG201, and represses precocious expression of WRKY53 and SAG201 in mature leaves by reducing H3K4me3 levels at these loci. Moreover, association of JMJ16 on WRKY53 and SAG201 loci increased at mature stage but decreased at later stage, suggesting that the age-dependent dynamic chromatin association of JMJ16 is required for precise transcriptional activation of SAGs during leaf senescence. Thus, JMJ16 is an important regulator of leaf senescence that demethylates H3K4 at senescence-associated genes in an age-dependent manner. Overall design: Examination of the difference of transcriptomes, H3K4me3 modifications and JMJ16 binding in Col and jmj16 KO Arabidopsis. Less...