Project description:Using Western blot, we found the level of H3K27me3, but not H3K4me3, H3K9me2 and H3K36me3, was specifically reduced in the tor-es mutant. To gain a genome-wide view of the effects of TOR activity on H3K27me3 distribution, we performed quantitative chromatin immunoprecipitation with an exogenous reference genome (ChIP-Rx) followed by deep-sequencing. We find a global reduction of H3K27me3 occupancy in tor-es, whereas the H3K9me2 level was largely unaffected. These results suggest that TOR may be a specific and direct regulator of global deposition of H3K27me3. To investigate the function of TOR phosphorylation of FIE, we complemented the heterozygous fie/+ plants with GFP-FIE or the phosphorylation site mutant (SSTS/AAAA) under the control of the FIE promoter. To provide a parallel comparison with SSTS/AAAA/fie, we generated estradiol-inducible fie-amiR-es transgenic lines, that eliminated FIE protein. Quantitative ChIP-seq analyses revealed greatly reduced H3K27me3 levels across the genome in SSTS/AAAA and fie-amiR-es mutants. And transcriptome profiling by RNA-Seq was conducted to globally identify thousands of genes coordinately dysregulated in the shoots of SSTS/AAAA and fie-amiR-es plants. Furthermore, gene Ontology analysis of 986 TOR-FIE-PRC2 target genes revealed significant enrichment for transcription factors/regulators controlling a broad spectrum of developmental programs.
Project description:Arabidopsis telomeric repeat binding factors (TRBs) can bind telomeric DNA sequences to protect telomeres from degradation. TRBs can also recruit Polycomb Repressive Complex 2 (PRC2) to deposit tri-methylation of H3 lysine 27 (H3K27me3) over certain target loci. Here, we demonstrate that TRBs also associate and colocalize with JUMONJI14 (JMJ14) and trigger H3K4me3 demethylation at some loci. The trb1/2/3 triple mutant and the jmj14-1 mutant show an increased level of H3K4me3 over TRB and JMJ14 binding sites, resulting in up-regulation of their target genes. Furthermore, tethering TRBs to the promoter region of genes with an artificial zinc finger (TRB-ZF) successfully triggers target gene silencing, as well as H3K27me3 deposition, and H3K4me3 removal. Interestingly, JMJ14 is predominantly recruited to ZF off-target sites with low levels of H3K4me3, which is accompanied with TRB-ZFs triggered H3K4me3 removal at these loci. These results suggest that TRB proteins coordinate PRC2 and JMJ14 activities to repress target genes via H3K27me3 deposition and H3K4me3 removal.
Project description:In this study, we examined the genome-wide deposition of two opposing histone modifications H3K4me3 and H3K27me3, in mid-maturation (stage B1) soybean embryos.
Project description:Histone marks H3K27me3 and H3K4me3 are mutual exclusive over plant genome, however, the underlying mechanism is not fully understood. Arabidopsis telomeric repeat binding factors (TRBs) are required for the deposition of H3K27me3 by recruiting Polycomb repressive complexes (PRCs). Here, we demonstrate that TRBs associate and colocalize with JUMONJI 14 (JMJ14) over gene body regions and trigger H3K4me3 demethylation. The trb1/2/3 triple mutant and jmj14-1 mutant show an increased level of H3K4me3 over TRB and JMJ14 binding sites, resulting in up-regulation of their targeting genes. Furthermore, tethering TRBs to the promoter region of genes with an artificial zinc finger successfully triggers target gene silencing. These results suggest that TRB proteins cooperate with PRC2 and JMJ14 complex to repress target gene by H3K4me3 demethylation and H3K27me3 deposition.
Project description:To investigate the effect of the OsINO80, we analysed OsINO80 binding regions and analysed genome-wide H3, H2A, H2A.Z, H2Aub, H3K9me2, H3K4me2, H3K4me3, H3K27me3, and H3K36me3 in the mutant and WT by ChIP-seq.
Project description:Epigenetic mechanisms set apart the active and inactive regions in the genome of multicellular organisms to produce distinct cell fates during embryogenesis. Here, we report on the epigenetic and transcriptome genome-wide maps of gastrula-stage Xenopus tropicalis embryos using massive parallel sequencing of cDNA (RNA-seq) and DNA obtained by chromatin immunoprecipitation (ChIP-seq) of histone H3 K4 and K27 trimethylation and RNA Polymerase II (RNAPII). These maps identify promoters and transcribed regions. Strikingly, genomic regions featuring opposing histone modifications are mostly transcribed, reflecting spatially regulated expression rather than bivalency as determined by expression profile analyses, sequential ChIP, and ChIP-seq on dissected embryos. Spatial differences in H3K27me3 deposition are predictive of localized gene expression. Moreover, the appearance of H3K4me3 coincides with zygotic gene activation, whereas H3K27me3 is predominantly deposited upon subsequent spatial restriction or repression of transcriptional regulators. These results reveal a hierarchy in the spatial control of zygotic gene activation. ChIP-seq profiles of two histone modifications (H3K4me3 and H3K27me3) and RNA Polymerase II, and a RNA-seq profile, of gastrula stage Xenopus tropicalis embryos