Project description:We reported that ethylene specifically elevated acetylation of histone H3 at K14 and the non-canonical acetylation of histone H3 at K23,but not H3K9ac.Thus, we further performed Chip-sequencing of H3K9Ac, using chromatins isolated from 3-day old etiolated ein2-5 seedlings treated with ethylene or air gas.
Project description:We report that ethylene specifically elevated acetylation of histone H3 at K14 and the non-canonical acetylation of histone H3 at K23. We perform Chip-sequencing of H3K14Ac, H3K23Ac and H3K9Ac using chromatins isolated from 3-day old etiolated Col-0 seedlings treated with ethylene or air gas. Results show that ethylene specifically elevates H3K14Ac and non-canonical H3K23Ac in EIN3 targeted genes that are regulated at the transcriptional level by ethylene.
Project description:Ethylene gas is essential for many developmental processes and stress responses in plants. ETHYLENE INSENSITIVE2 (EIN2), an NRAMP-homologous integral membrane protein, plays an essential role in ethylene signaling but its function remains enigmatic. Here we report that phosphorylation-regulated proteolytic processing of EIN2 triggers its endoplasmic reticulum (ER)-nucleus translocation, which is essential for hormone signaling and response in Arabidopsis. Without ethylene, or in hormone receptors mutants, ER-tethered EIN2 shows CTR1 kinase-dependent phosphorylation. Ethylene exposure triggers dephosphorylation and proteolytic cleavage, resulting in rapid nuclear translocation of a carboxyl-terminal EIN2 fragment (C’). Plants containing mutations that mimic EIN2 dephosphorylation, or inactivate CTR1, show constitutive cleavage and nuclear localization of EIN2-C’, and EIN3/EIL1-dependent activation of ethylene responses. These findings uncover a mechanism of subcellular communication whereby ethylene gas stimulates rapid phosphorylation-dependent cleavage and nuclear movement of the EIN2-C’ peptide, thus linking hormone perception and signaling components located in the ER with nuclear-localized transcriptional regulators.
Project description:Here we report the identification of 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 SUBUNIT6). By applying high-throughput profiling of histone modifications, histone variant occupancy, cytosine methylation and mRNA expression in various Arabidopsis mutants, we identified ETHYLENE-INSENSITIVE2 (EIN2) as a direct target of EIN6 (REF6) and EEN. EIN6 (REF6) and EEN as part of the INO80 complex interdependently and uniquely 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 functional 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 and subsequent collapse of the entire ethylene transcriptional cascade.
Project description:A complex interplay between ethylene, ETP1/ETP2 F-box proteins, and degradation of EIN2 is essential for triggering ethylene responses in plants. The gaseous plant hormone ethylene can trigger myriad physiological and morphological responses in plants. While many ethylene signaling pathway components have been identified and characterized, little is known about the function of the integral membrane protein EIN2, a central regulator of all ethylene responses. Here, we demonstrate that Arabidopsis thaliana EIN2 is a protein with a short half-life that undergoes rapid proteasome-mediated protein turnover. Moreover, EIN2 protein accumulation is positively regulated by ethylene. We identified two F-box proteins, EIN2 TARGETING PROTEIN and 2 (ETP1 and ETP2), that interact with the EIN2 carboxyl-terminal domain (CEND), which is highly conserved and sufficient to activate most ethylene responses. Overexpression of ETP1 or ETP2 disrupts EIN2 protein accumulation, and these plants manifest a strong ethylene insensitive phenotype. Furthermore, knocking down the levels of both ETP1 and ETP2 mRNAs using an artificial microRNA (amiRNA) leads to accumulation of EIN2 protein, resulting in plants that display constitutive ethylene response phenotypes. Finally, ethylene down-regulates ETP1 and ETP2 proteins, impairing their ability to interact with EIN2. Thus, these studies reveal that a complex interplay between ethylene, the regulation of ETP1/ETP2 F-box proteins, and subsequent targeting and degradation of EIN2 is essential for triggering ethylene responses in plants. Keywords: ethylene treatment, genetic modification
Project description:Seed size is related to plant evolution and crop yield and is affected by genetic mutations, imprinting, and genome dosage. Imprinting is a widespread epigenetic phenomenon in mammals and flowering plants. ETHYLENE INSENSITIVE2 (EIN2) encodes a membrane protein that links the ethylene perception to transcriptional regulation. Interestingly, during seed development EIN2 is maternally-expressed in Arabidopsis and maize, but the role of EIN2 in seed development is unknown. Here we show that EIN2 is expressed specifically in the endosperm, and the maternal-specific EIN2 expression affects temporal regulation of endosperm cellularization. As a result, seed size increases in the genetic cross using the ein2 mutant as the maternal parent or in the ein2 mutant. The maternal-specific expression of EIN2 in the endosperm is controlled by DNA methylation but not by H3K27me3 or by ethylene and several ethylene pathway genes tested. RNA-seq analysis in the endosperm isolated by laser-capture microdissection show upregulation of many endosperm-expressed genes such as AGAMOUS-LIKEs (AGLs) in the ein2 mutant or when the maternal EIN2 allele is not expressed. EIN2 does not interact with DNA and may act through ETHYLENE INSENSITIVE3 (EIN3), a DNA binding protein present in sporophytic tissues, to activate target genes like AGLs, which in turn mediate temporal regulation of endosperm cellularization and seed size. These results provide mechanistic insights into endosperm and maternal-specific expression of EIN2 on endosperm cellularization and seed development, which could help improve seed production in plants and crops.
Project description:A complex interplay between ethylene, ETP1/ETP2 F-box proteins, and degradation of EIN2 is essential for triggering ethylene responses in plants. The gaseous plant hormone ethylene can trigger myriad physiological and morphological responses in plants. While many ethylene signaling pathway components have been identified and characterized, little is known about the function of the integral membrane protein EIN2, a central regulator of all ethylene responses. Here, we demonstrate that Arabidopsis thaliana EIN2 is a protein with a short half-life that undergoes rapid proteasome-mediated protein turnover. Moreover, EIN2 protein accumulation is positively regulated by ethylene. We identified two F-box proteins, EIN2 TARGETING PROTEIN and 2 (ETP1 and ETP2), that interact with the EIN2 carboxyl-terminal domain (CEND), which is highly conserved and sufficient to activate most ethylene responses. Overexpression of ETP1 or ETP2 disrupts EIN2 protein accumulation, and these plants manifest a strong ethylene insensitive phenotype. Furthermore, knocking down the levels of both ETP1 and ETP2 mRNAs using an artificial microRNA (amiRNA) leads to accumulation of EIN2 protein, resulting in plants that display constitutive ethylene response phenotypes. Finally, ethylene down-regulates ETP1 and ETP2 proteins, impairing their ability to interact with EIN2. Thus, these studies reveal that a complex interplay between ethylene, the regulation of ETP1/ETP2 F-box proteins, and subsequent targeting and degradation of EIN2 is essential for triggering ethylene responses in plants. Experiment Overall Design: Six samples were analyzed. There were three treatments with two biological replicates each. The treatments are as follows: 8 week old Col-0 plants (air control), 8 week old Col-0 plants treated for 24 hours with ethylene gas (10 ppm), and artificial microRNA knockdown mutants, amiR-ETP1/2.