Project description:KDM2A/FBXL11 is a Jumonji-domain containing lysine demethylase catalyzing the removal of mono- and di-methyl modifications of histone H3 lysine 36. While Kdm2a is required for mouse embryogenesis, its role in adult physiology is unknown. Using conditional deletion approaches, we demonstrate that Kdm2a deficiency causes testicular atrophy and male infertility. Though spermatogonial stem cells were unaffected, proliferating and differentiating spermatogonia suffered from delayed cell cycle progression and apoptosis, which correlated with upregulated expression of several cell cycle inhibitors. Loss of Kdm2a in spermatocytes disrupted progression through meiotic prophase, as shown by impaired chromosome synapsis and processing of meiotic double strand breaks, and by altered chromatin states. Correspondingly, Kdm2a mutant spermatocytes failed to activate numerous genes controlling these processes. RNA-sequencing analyses on purified spermatogonia and spermatocytes showed that during normal spermatogonial differentiation over 700 genes undergo repression, which is controlled by KDM2A. CpG-rich promoter genes upregulated in Kdm2a deficient cells are marked by Polycomb Repressive Complexes (PRC) and associated modifications in wildtype male germ cells, suggesting that KDM2A is required for PRC-mediated repression. Our study thus identifies critical roles for KDM2A in coordinating gene expression programs during spermatogonial differentiation and meiosis, which are essential for male germ cell development.
Project description:KDM2A/FBXL11 is a Jumonji-domain containing lysine demethylase catalyzing the removal of mono- and di-methyl modifications of histone H3 lysine 36. While Kdm2a is required for mouse embryogenesis, its role in adult physiology is unknown. Using conditional deletion approaches, we demonstrate that Kdm2a deficiency causes testicular atrophy and male infertility. Though spermatogonial stem cells were unaffected, proliferating and differentiating spermatogonia suffered from delayed cell cycle progression and apoptosis, which correlated with upregulated expression of several cell cycle inhibitors. Loss of Kdm2a in spermatocytes disrupted progression through meiotic prophase, as shown by impaired chromosome synapsis and processing of meiotic double strand breaks, and by altered chromatin states. Correspondingly, Kdm2a mutant spermatocytes failed to activate numerous genes controlling these processes. RNA-sequencing analyses on purified spermatogonia and spermatocytes showed that during normal spermatogonial differentiation over 700 genes undergo repression, which is controlled by KDM2A. CpG-rich promoter genes upregulated in Kdm2a deficient cells are marked by Polycomb Repressive Complexes (PRC) and associated modifications in wildtype male germ cells, suggesting that KDM2A is required for PRC-mediated repression. Our study thus identifies critical roles for KDM2A in coordinating gene expression programs during spermatogonial differentiation and meiosis, which are essential for male germ cell development.
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: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:A potent inhibitor of the JmjC histone lysine demethylase KDM2A (compound 35, pIC50 7.2) with excellent selectivity over representatives from other KDM subfamilies has been developed; the discovery that a triazolopyridine compound binds to the active site of JmjC KDMs was followed by optimisation of the triazole substituent for KDM2A inhibition and selectivity.
