RESUMO
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RESUMO
Understanding the systems-level actions of transcriptional responses to hormones provides insight into how the genome is reprogrammed in response to environmental stimuli. Here, we investigated the signalling pathway of the hormone jasmonic acid (JA), which controls a plethora of critically important processes in plants and is orchestrated by the transcription factor MYC2 and its closest relatives in Arabidopsis thaliana. We generated an integrated framework of the response to JA, which spans from the activity of master and secondary regulatory transcription factors, through gene expression outputs and alternative splicing, to protein abundance changes, protein phosphorylation and chromatin remodelling. We integrated time-series transcriptome analysis with (phospho)proteomic data to reconstruct gene regulatory network models. These enabled us to predict previously unknown points of crosstalk of JA to other signalling pathways and to identify new components of the JA regulatory mechanism, which we validated through targeted mutant analysis. These results provide a comprehensive understanding of how a plant hormone remodels cellular functions and plant behaviour, the general principles of which provide a framework for analyses of cross-regulation between other hormone and stress signalling pathways.
Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Ciclopentanos/metabolismo , Redes Reguladoras de Genes , Oxilipinas/metabolismo , Fosfoproteínas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Transdução de Sinais , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Perfilação da Expressão Gênica , Reguladores de Crescimento de Plantas/genética , Proteômica , Transativadores/genética , Transativadores/metabolismoRESUMO
The central regulator of the ethylene (ET) signaling pathway, which controls a plethora of developmental programs and responses to environmental cues in plants, is ETHYLENE-INSENSITIVE2 (EIN2). Here we identify a chromatin-dependent regulatory mechanism at EIN2 requiring two genes: ETHYLENE-INSENSITIVE6 (EIN6), which is a H3K27me3 demethylase also known as RELATIVE OF EARLY FLOWERING6 (REF6), and EIN6 ENHANCER (EEN), the Arabidopsis homolog of the yeast INO80 chromatin remodeling complex subunit IES6 (INO EIGHTY SUBUNIT). Strikingly, EIN6 (REF6) and the INO80 complex redundantly control the level and the localization of the repressive histone modification H3K27me3 and the histone variant H2A.Z at the 5' untranslated region (5'UTR) intron of EIN2. Concomitant loss of EIN6 (REF6) and the INO80 complex shifts the chromatin landscape at EIN2 to a repressive state causing a dramatic reduction of EIN2 expression. These results uncover a unique type of chromatin regulation which safeguards the expression of an essential multifunctional plant stress regulator.
