Project description:Haploid embryos can be induced from cultured immature pollen following a stress treatment. In Brassica napus, application of the histone/lysine deacetylase (HDAC/KDAC) inhibitor trichostatin A (TSA) to pollen cultures enhances the production of differentiated embryos and embryogenic callus when applied together with heat stress (Li et al., 2014). To identify genes associated with the induction of B. napus haploid embryogenesis, we compared the transcriptomes of untreated pollen cultures and pollen cultures treated with either heat-stress or heat-stress plus TSA.
Project description:The haploid multicellular male gametophyte of plants, the pollen grain, is a terminally differentiated structure whose function ends at fertilization. Unlike pollen grains, the immature gametophyte retains its capacity for totipotent growth when cultured in vitro. Haploid embryo production from cultured immature male gametophytes is a widely used plant breeding and propagation technique that was described nearly 50 years ago, but one that is poorly understood at the mechanistic level. Using a chemical approach, we show that the switch to haploid embryogenesis is controlled by the activity of histone deacetylases (HDACs). Blocking HDAC activity with trichostatin A (TSA) in cultured immature male gametophytes of Brassica napus leads to a large increase in the proportion of cells that switch from pollen to embryogenic growth. Embryogenic growth is enhanced by, but not dependent on, the high temperature stress that is normally used to induce haploid embryogenesis in B. napus. The immature male gametophyte of Arabidopsis thaliana, which is recalcitrant for haploid embryo development in culture, also forms embryogenic cell clusters after TSA treatment. TSA treatment of immature male gametophytes for as little as eight hours was accompanied by hyperacetylation of histones H3 and H4, and by the upregulation of genes involved in cell-cycle progression, the auxin pathway and cell wall catabolism pathways. We propose that the totipotency of the immature male gametophyte in planta is kept in check by an HDAC-dependent mechanism, and that high temperature or other stresses used to induce haploid embryo development in culture impinge on this HDAC-dependent pathway. 8 samples were analyzed. We generated the following pairwise comparisons between treatment and the corresponding mock treatment: TSA+CHX (2 replicates) vs CHX (2 replicates); TSA (2 replicates) vs DMSO (2 replicates).
Project description:HDAC inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. Often studied at single loci, increased histone acetylation is the paradigmatic mechanism of action, however, little is known of the extent of genome-wide changes of the mammalian genome when stimulated by the hydroxamic acids, TSA and SAHA. In primary human vascular endothelial cells we map the chromatin modifications, histone H3 acetylation of lysine 9 and 14 (H3K9/14ac) using chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq). Since acetylation mediated gene expression is often associated with modification of other lysine residues we also examined H3K4me3 and H3K9me3 as well as changes in CpG methylation (CpG-seq). Genome-wide mRNA sequencing indicates the differential expression of about 30% of genes, with almost equal numbers being up- and down- regulated. We observe deacetylation conferred by TSA and SAHA that are associated with decreased gene expression. Histone deacetylation is associated with the loss of p300/CBP binding at gene promoters. This study provides an important framework for HDAC inhibitor function in vascular biology and a comprehensive description of genome-wide deacetylation. HAEC mRNA profiles of TSA treated and control samples were generated by deep sequencing, in triplicate, using Illumina GAIIx.
Project description:HDAC inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. Often studied at single loci, increased histone acetylation is the paradigmatic mechanism of action, however, little is known of the extent of genome-wide changes of the mammalian genome when stimulated by the hydroxamic acids, TSA and SAHA. In primary human vascular endothelial cells we map the chromatin modifications, histone H3 acetylation of lysine 9 and 14 (H3K9/14ac) using chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq). Since acetylation mediated gene expression is often associated with modification of other lysine residues we also examined H3K4me3 and H3K9me3 as well as changes in CpG methylation (CpG-seq). Genome-wide mRNA sequencing indicates the differential expression of about 30% of genes, with almost equal numbers being up- and down- regulated. We observe deacetylation conferred by TSA and SAHA that are associated with decreased gene expression. Histone deacetylation is associated with the loss of p300/CBP binding at gene promoters. This study provides an important framework for HDAC inhibitor function in vascular biology and a comprehensive description of genome-wide deacetylation. HAEC ChIP-seq profiles for 3 histone marks of TSA treated and control samples were generated by deep sequencing, in triplicate, using Illumina GAIIx.
Project description:HDAC inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. Often studied at single loci, increased histone acetylation is the paradigmatic mechanism of action, however, little is known of the extent of genome-wide changes of the mammalian genome when stimulated by the hydroxamic acids, TSA and SAHA. In primary human vascular endothelial cells we map the chromatin modifications, histone H3 acetylation of lysine 9 and 14 (H3K9/14ac) using chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq). Since acetylation mediated gene expression is often associated with modification of other lysine residues we also examined H3K4me3 and H3K9me3 as well as changes in CpG methylation (CpG-seq). Genome-wide mRNA sequencing indicates the differential expression of about 30% of genes, with almost equal numbers being up- and down- regulated. We observe deacetylation conferred by TSA and SAHA that are associated with decreased gene expression. Histone deacetylation is associated with the loss of p300/CBP binding at gene promoters. This study provides an important framework for HDAC inhibitor function in vascular biology and a comprehensive description of genome-wide deacetylation. HAEC MethylMiner profiles of TSA treated and control samples were generated by deep sequencing, in triplicate, using Illumina GAIIx.
Project description:HDAC inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. Often studied at single loci, increased histone acetylation is the paradigmatic mechanism of action, however, little is known of the extent of genome-wide changes of the mammalian genome when stimulated by the hydroxamic acids, TSA and SAHA. In primary human vascular endothelial cells we map the chromatin modifications, histone H3 acetylation of lysine 9 and 14 (H3K9/14ac) using chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq). Since acetylation mediated gene expression is often associated with modification of other lysine residues we also examined H3K4me3 and H3K9me3 as well as changes in CpG methylation (CpG-seq). Genome-wide mRNA sequencing indicates the differential expression of about 30% of genes, with almost equal numbers being up- and down- regulated. We observe deacetylation conferred by TSA and SAHA that are associated with decreased gene expression. Histone deacetylation is associated with the loss of p300/CBP binding at gene promoters. This study provides an important framework for HDAC inhibitor function in vascular biology and a comprehensive description of genome-wide deacetylation.
Project description:HDAC inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. Often studied at single loci, increased histone acetylation is the paradigmatic mechanism of action, however, little is known of the extent of genome-wide changes of the mammalian genome when stimulated by the hydroxamic acids, TSA and SAHA. In primary human vascular endothelial cells we map the chromatin modifications, histone H3 acetylation of lysine 9 and 14 (H3K9/14ac) using chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq). Since acetylation mediated gene expression is often associated with modification of other lysine residues we also examined H3K4me3 and H3K9me3 as well as changes in CpG methylation (CpG-seq). Genome-wide mRNA sequencing indicates the differential expression of about 30% of genes, with almost equal numbers being up- and down- regulated. We observe deacetylation conferred by TSA and SAHA that are associated with decreased gene expression. Histone deacetylation is associated with the loss of p300/CBP binding at gene promoters. This study provides an important framework for HDAC inhibitor function in vascular biology and a comprehensive description of genome-wide deacetylation.
Project description:HDAC inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. Often studied at single loci, increased histone acetylation is the paradigmatic mechanism of action, however, little is known of the extent of genome-wide changes of the mammalian genome when stimulated by the hydroxamic acids, TSA and SAHA. In primary human vascular endothelial cells we map the chromatin modifications, histone H3 acetylation of lysine 9 and 14 (H3K9/14ac) using chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq). Since acetylation mediated gene expression is often associated with modification of other lysine residues we also examined H3K4me3 and H3K9me3 as well as changes in CpG methylation (CpG-seq). Genome-wide mRNA sequencing indicates the differential expression of about 30% of genes, with almost equal numbers being up- and down- regulated. We observe deacetylation conferred by TSA and SAHA that are associated with decreased gene expression. Histone deacetylation is associated with the loss of p300/CBP binding at gene promoters. This study provides an important framework for HDAC inhibitor function in vascular biology and a comprehensive description of genome-wide deacetylation.
Project description:The haploid multicellular male gametophyte of plants, the pollen grain, is a terminally differentiated structure whose function ends at fertilization. Unlike pollen grains, the immature gametophyte retains its capacity for totipotent growth when cultured in vitro. Haploid embryo production from cultured immature male gametophytes is a widely used plant breeding and propagation technique that was described nearly 50 years ago, but one that is poorly understood at the mechanistic level. Using a chemical approach, we show that the switch to haploid embryogenesis is controlled by the activity of histone deacetylases (HDACs). Blocking HDAC activity with trichostatin A (TSA) in cultured immature male gametophytes of Brassica napus leads to a large increase in the proportion of cells that switch from pollen to embryogenic growth. Embryogenic growth is enhanced by, but not dependent on, the high temperature stress that is normally used to induce haploid embryogenesis in B. napus. The immature male gametophyte of Arabidopsis thaliana, which is recalcitrant for haploid embryo development in culture, also forms embryogenic cell clusters after TSA treatment. TSA treatment of immature male gametophytes for as little as eight hours was accompanied by hyperacetylation of histones H3 and H4, and by the upregulation of genes involved in cell-cycle progression, the auxin pathway and cell wall catabolism pathways. We propose that the totipotency of the immature male gametophyte in planta is kept in check by an HDAC-dependent mechanism, and that high temperature or other stresses used to induce haploid embryo development in culture impinge on this HDAC-dependent pathway.
Project description:HDAC inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. Often studied at single loci, increased histone acetylation is the paradigmatic mechanism of action, however, little is known of the extent of genome-wide changes of the mammalian genome when stimulated by the hydroxamic acids, TSA and SAHA. In primary human vascular endothelial cells we map the chromatin modifications, histone H3 acetylation of lysine 9 and 14 (H3K9/14ac) using chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq). Since acetylation mediated gene expression is often associated with modification of other lysine residues we also examined H3K4me3 and H3K9me3 as well as changes in CpG methylation (CpG-seq). Genome-wide mRNA sequencing indicates the differential expression of about 30% of genes, with almost equal numbers being up- and down- regulated. We observe deacetylation conferred by TSA and SAHA that are associated with decreased gene expression. Histone deacetylation is associated with the loss of p300/CBP binding at gene promoters. This study provides an important framework for HDAC inhibitor function in vascular biology and a comprehensive description of genome-wide deacetylation. Mouse ChIP-seq profiles for histone acetylation treated and control samples were generated by deep sequencing, using Illumina GAIIx.