Project description:In higher eukaryotes, up to 70% of genes have high levels of nonmethylated cytosine/guanine base pairs (CpGs) surrounding promoters and gene regulatory units. These features, called CpG islands, were identified over 20 years ago, but there remains little mechanistic evidence to suggest how these enigmatic elements contribute to promoter function, except that they are refractory to epigenetic silencing by DNA methylation. Here we show that CpG islands directly recruit the H3K36-specific lysine demethylase enzyme KDM2A. Nucleation of KDM2A at these elements results in removal of H3K36 methylation, creating CpG island chromatin that is uniquely depleted of this modification. KDM2A utilizes a zinc finger CxxC (ZF-CxxC) domain that preferentially recognizes nonmethylated CpG DNA, and binding is blocked when the CpG DNA is methylated, thus constraining KDM2A to nonmethylated CpG islands. These data expose a straightforward mechanism through which KDM2A delineates a unique architecture that differentiates CpG island chromatin from bulk chromatin.
Project description:This SuperSeries is composed of the following subset Series: GSE18588: CpG islands recruit a histone H3 lysine 36 demethylase [Illumina sequencing data] GSE21201: CpG islands recruit a histone H3 lysine 36 demethylase [Agilent data] Refer to individual Series
Project description:Transcription factors that bind small DNA motifs embedded in promoters play a central role in controlling gene expression. However, in addition to these elements, up to 70% of genes in higher eukaryotes also have high levels of non-methylated cytosine/guanine base pairs (CpGs) surrounding promoters and gene regulatory units. These features, called CpG islands, were identified over twenty years ago but there remains little mechanistic evidence to suggest how these enigmatic elements contribute to promoter function, with the exception that they are refractory to epigenetic silencing by DNA methylation. Here we show that CpG islands directly recruit the H3K36 specific lysine demethylase enzyme KDM2A. Genome wide analyses by ChIP-seq demonstrated a striking global association of KDM2A with CpG islands. Nucleation of KDM2A at these elements resulted in removal of H3K36 methylation creating CpG island chromatin that is uniquely depleted of this modification. KDM2A utilizes a zinc finger CxxC (ZF-CxxC) domain that specifically recognizes non-methylated CpG DNA and binding is blocked when the CpG DNA is methylated, thus constraining KDM2A to nonmethylated CpG islands. These data expose a remarkably straightforward mechanism through which KDM2A delineates a unique architecture that differentiates CpG island chromatin from bulk chromatin.
Project description:Transcription factors that bind small DNA motifs embedded in promoters play a central role in controlling gene expression. However, in addition to these elements, up to 70% of genes in higher eukaryotes also have high levels of non-methylated cytosine/guanine base pairs (CpGs) surrounding promoters and gene regulatory units. These features, called CpG islands, were identified over twenty years ago but there remains little mechanistic evidence to suggest how these enigmatic elements contribute to promoter function, with the exception that they are refractory to epigenetic silencing by DNA methylation. Here we show that CpG islands directly recruit the H3K36 specific lysine demethylase enzyme KDM2A. Genome wide analyses by ChIP-seq demonstrated a striking global association of KDM2A with CpG islands. Nucleation of KDM2A at these elements resulted in removal of H3K36 methylation creating CpG island chromatin that is uniquely depleted of this modification. KDM2A utilizes a zinc finger CxxC (ZF-CxxC) domain that specifically recognizes non-methylated CpG DNA and binding is blocked when the CpG DNA is methylated, thus constraining KDM2A to nonmethylated CpG islands. These data expose a remarkably straightforward mechanism through which KDM2A delineates a unique architecture that differentiates CpG island chromatin from bulk chromatin. Two cell lines were used in this study: a control line (LMP) with wildtype levels of KDM2A, and a KDM2A knockdown line (RNAi) in which KDM2A levels were depleted by approximately 60% using an shRNA-based approach. For each cell line, RNA was extracted from cells collected on two different dates (rep1 and rep2).
Project description:Eukaryotic gene expression profiles are largely defined by transcription factors that recognize specific DNA sequences in gene regulatory regions and impact RNA polymerase recruitment and transcription. In addition to specific core promoter regulatory elements, up to 70% of genes in higher eukaryotes are also characterized by an overrepresentation of cytosine/guanine base pairs (CpGs) surrounding promoters and gene regulatory units. These features, called CpG islands, were identified over twenty years ago but there remains little mechanistic evidence to suggest how these enigmatic elements contribute to promoter function, with the exception that they are refractory to epigenetic silencing by DNA methylation. Here we uncover a role for CpG islands in buffering gene regulatory elements from repressive histone H3 lysine 36 methylation by directly recruiting the H3K36 specific lysine demethylase enzyme KDM2A. KDM2A is recruited to CpG islands by a zinc finger CxxC (ZF-CxxC) domain that specifically recognizes CpG DNA and is blocked by DNA methylation. This capacity to sense the epigenetic methylation state of DNA constrains KDM2A to non-methylated CpG islands. Importantly, these observations suggest CpG islands may function to delineate gene regulatory elements from bulk chromatin by recruiting factors that create unique chromatin architecture.
Project description:Eukaryotic gene expression profiles are largely defined by transcription factors that recognize specific DNA sequences in gene regulatory regions and impact RNA polymerase recruitment and transcription. In addition to specific core promoter regulatory elements, up to 70% of genes in higher eukaryotes are also characterized by an overrepresentation of cytosine/guanine base pairs (CpGs) surrounding promoters and gene regulatory units. These features, called CpG islands, were identified over twenty years ago but there remains little mechanistic evidence to suggest how these enigmatic elements contribute to promoter function, with the exception that they are refractory to epigenetic silencing by DNA methylation. Here we uncover a role for CpG islands in buffering gene regulatory elements from repressive histone H3 lysine 36 methylation by directly recruiting the H3K36 specific lysine demethylase enzyme KDM2A. KDM2A is recruited to CpG islands by a zinc finger CxxC (ZF-CxxC) domain that specifically recognizes CpG DNA and is blocked by DNA methylation. This capacity to sense the epigenetic methylation state of DNA constrains KDM2A to non-methylated CpG islands. Importantly, these observations suggest CpG islands may function to delineate gene regulatory elements from bulk chromatin by recruiting factors that create unique chromatin architecture. This study provides information about binding of lysine demethylase enzyme KDM2A in mouse embryonic stem cells.
Project description:Recent discoveries of histone demethylases demonstrate that histone methylation is reversible. However, mechanisms governing the targeting and regulation of histone demethylation remain elusive. Here we report that a Drosophila melanogaster JmjC domain-containing protein, dKDM4A, is a histone H3K36 demethylase. dKDM4A specifically demethylates H3K36me2 and H3K36me3 both in vitro and in vivo. Affinity purification and mass spectrometry analysis revealed that heterochromatin protein 1a (HP1a) associates with dKDMA4A. We found that the chromo shadow domain of HP1a and a HP1-interacting motif of dKDM4A are responsible for this interaction. HP1a stimulates the histone H3K36 demethylation activity of dKDM4A, and this stimulation depends on the H3K9me-binding motif of HP1a. Finally, we provide in vivo evidence suggesting that HP1a and dKDM4A interact with each other and that loss of HP1a leads to an increased level of histone H3K36me3. Collectively, these results suggest a function of HP1a in transcription facilitating H3K36 demethylation at transcribed and/or heterochromatin regions.
Project description:Histone marks, carriers of epigenetic information, regulate gene expression. In mammalian cells, H3K36me3 is mainly catalyzed by SETD2 at gene body regions. Here, we find that in addition to gene body regions, H3K36me3 is enriched at promoters in primary cells. Through screening, we identify SMYD5, which is recruited to chromatin by RNA polymerase II, as a methyltransferase catalyzing H3K36me3 at promoters. The enzymatic activity of SMYD5 is dependent on its C-terminal glutamic acid-rich domain. Overexpression of full-length Smyd5, but not the C-terminal domain-truncated Smyd5, restores H3K36me3 at promoters in Smyd5 knockout cells. Furthermore, elevated Smyd5 expression contributes to tumorigenesis in liver hepatocellular carcinoma. Together, our findings identify SMYD5 as the H3K36me3 methyltransferase at promoters that regulates gene expression, providing insights into the localization and function of H3K36me3.