Project description:Dynamic histone H3K4 methylation is an important epigenetic component of transcriptional regulation. However, most of our current understanding of this histone mark is confined to regulation of transcriptional initiation. We now show that human LSD2/KDM1b/AOF1, the human homolog of LSD1, is a novel H3K4me1/2 demethylase that specifically regulates histone H3K4 methylation within intragenic regions of its target genes. Genome-wide mapping reveals that LSD2 associates predominantly with the gene bodies of actively transcribed genes, but is markedly absent from promoters. Depletion of endogenous LSD2 results in an increase of H3K4me2 as well as a decrease of H3K9me2 at LSD2 binding sites, and a consequent dysregulation of target gene transcription. Furthermore, characterization of LSD2 complex revealed that LSD2 forms active complexes with euchromatic histone methyltransferases EHMT1/2 and NSD3 as well as cellular factors involved in active transcription elongation. These data provide a possible molecular mechanism linking LSD2 to transcriptional regulation post initiation. We used microarray analysis to identify the subset of genes that are differentially expression after depletion of endogenous LSD2/KDM1b/AOF1. Retroviral shRNA targeting human LSD2 (5â-GTGGGACCACAATGAATTCTT -3â) and control shRNA was used to infect HeLa. RNA was purified 70 hours post infection and processed for Human Genome U133 Plus 2.0 Array (Affymetrix) hybridization per manufactureâs instructions. Biological duplicates were analyzed.
Project description:Dynamic histone H3K4 methylation is an important epigenetic component of transcriptional regulation. However, most of our current understanding of this histone mark is confined to regulation of transcriptional initiation. We now show that human LSD2/KDM1b/AOF1, the human homolog of LSD1, is a novel H3K4me1/2 demethylase that specifically regulates histone H3K4 methylation within intragenic regions of its target genes. Genome-wide mapping reveals that LSD2 associates predominantly with the gene bodies of actively transcribed genes, but is markedly absent from promoters. Depletion of endogenous LSD2 results in an increase of H3K4me2 as well as a decrease of H3K9me2 at LSD2 binding sites, and a consequent dysregulation of target gene transcription. Furthermore, characterization of LSD2 complex revealed that LSD2 forms active complexes with euchromatic histone methyltransferases EHMT1/2 and NSD3 as well as cellular factors involved in active transcription elongation. These data provide a possible molecular mechanism linking LSD2 to transcriptional regulation post initiation. We used microarray analysis to identify the subset of genes that are differentially expression after depletion of endogenous LSD2/KDM1b/AOF1.
Project description:Dynamic histone H3K4 methylation is an important epigenetic component of transcriptional regulation. However, most of our current understanding of this histone mark is confined to regulation of transcriptional initiation. We now show that human LSD2/KDM1b/AOF1, the human homolog of LSD1, is a novel H3K4me1/2 demethylase that specifically regulates histone H3K4 methylation within intragenic regions of its target genes. Genome-wide mapping reveals that LSD2 associates predominantly with the gene bodies of actively transcribed genes, but is markedly absent from promoters. Depletion of endogenous LSD2 results in an increase of H3K4me2 as well as a decrease of H3K9me2 at LSD2 binding sites, and a consequent dysregulation of target gene transcription. Furthermore, characterization of LSD2 complex revealed that LSD2 forms active complexes with euchromatic histone methyltransferases EHMT1/2 and NSD3 as well as cellular factors involved in active transcription elongation. These data provide a possible molecular mechanism linking LSD2 to transcriptional regulation post initiation.
Project description:Lysine-specific demethylase 1 (LSD1) is an epigenetic enzyme that oxidatively cleaves methyl groups from monomethyl and dimethyl Lys4 of histone H3 (H3K4Me1, H3K4Me2) and can contribute to gene silencing. This study describes the design and synthesis of analogs of a monoamine oxidase antidepressant, phenelzine, and their LSD1 inhibitory properties. A novel phenelzine analog (bizine) containing a phenyl-butyrylamide appendage was shown to be a potent LSD1 inhibitor in vitro and was selective versus monoamine oxidases A/B and the LSD1 homolog, LSD2. LSD1 inhibitor bizine was found to be effective at modulating bulk histone methylation in cancer cells, and ChIP-seq experiments revealed a statistically significant overlap in the H3K4 methylation pattern of genes affected by bizine and those altered in LSD1-/- cells. Treatment of two cancer cell lines, LNCaP and H460 with bizine conferred a reduction in proliferation rate, and bizine showed additive to synergistic effects on cell growth when used in combination with two out of five HDAC inhibitors tested. Moreover, neurons exposed to oxidative stress were protected by the presence of bizine, suggesting potential applications in neurodegenerative disease.
Project description:To understand what dictates the emerging patterns of de novo DNA methylation, we mapped DNA methylation, chromatin, and transcription changes in purified fetal mouse germ cells using MIRA-chip, ChIP-chip, and strand-specific RNA-seq, respectively. De novo methylation occurred without any apparent trigger from preexisting repressing chromatin marks but was preceded by broad, low-level transcription along the entire genome in prospermatogonia. Only distinct short sequences remained unmethylated, precisely aligned with constitutive or emerging peaks of H3K4me2. Establishment of methylation at differentially methylated regions (DMRs) of imprinted genes, CpG islands, and IAPs followed these same default rules. Transcription run-through occurred at paternal DMRs with no- or diminishing H3K4me2 peaks. Maternal DMRs remained unmethylated among highly methylated DNA at precisely aligned H3K4me2 peaks with transcription initiating at least in one strand. Our results suggest that the pattern of de novo DNA methylation in prospermatogonia is dictated by opposing actions of broad, low-level transcription and dynamic patterns of active chromatin. ChIP-chip and MIRA-chip were performed to map histone modifications and DNA methylation at different devlopmental time points in germ cells and somatic cells along known imprinted domains and control regions, using custom NimbleGen tiling arrays.
Project description:To understand what dictates the emerging patterns of de novo DNA methylation, we mapped DNA methylation, chromatin, and transcription changes in purified fetal mouse germ cells using MIRA-chip, ChIP-chip, and strand-specific RNA-seq, respectively. De novo methylation occurred without any apparent trigger from preexisting repressing chromatin marks but was preceded by broad, low-level transcription along the entire genome in prospermatogonia. Only distinct short sequences remained unmethylated, precisely aligned with constitutive or emerging peaks of H3K4me2. Establishment of methylation at differentially methylated regions (DMRs) of imprinted genes, CpG islands, and IAPs followed these same default rules. Transcription run-through occurred at paternal DMRs with no- or diminishing H3K4me2 peaks. Maternal DMRs remained unmethylated among highly methylated DNA at precisely aligned H3K4me2 peaks with transcription initiating at least in one strand. Our results suggest that the pattern of de novo DNA methylation in prospermatogonia is dictated by opposing actions of broad, low-level transcription and dynamic patterns of active chromatin.
Project description:To understand what dictates the emerging patterns of de novo DNA methylation, we mapped DNA methylation, chromatin, and transcription changes in purified fetal mouse germ cells using MIRA-chip, ChIP-chip, and strand-specific RNA-seq, respectively. De novo methylation occurred without any apparent trigger from preexisting repressing chromatin marks but was preceded by broad, low-level transcription along the entire genome in prospermatogonia. Only distinct short sequences remained unmethylated, precisely aligned with constitutive or emerging peaks of H3K4me2. Establishment of methylation at differentially methylated regions (DMRs) of imprinted genes, CpG islands, and IAPs followed these same default rules. Transcription run-through occurred at paternal DMRs with no- or diminishing H3K4me2 peaks. Maternal DMRs remained unmethylated among highly methylated DNA at precisely aligned H3K4me2 peaks with transcription initiating at least in one strand. Our results suggest that the pattern of de novo DNA methylation in prospermatogonia is dictated by opposing actions of broad, low-level transcription and dynamic patterns of active chromatin.