Project description:H3K4 demethylation by Jarid1a and Jarid1b contributes to retinoblastoma-mediated gene silencing during cellular senescence (expression)
Project description:H3K4 demethylation by Jarid1a and Jarid1b contributes to retinoblastoma-mediated gene silencing during cellular senescence (ChIP-seq)
Project description:Cellular senescence is a tumor-suppressive program that involves chromatin reorganization and specific changes in gene expression that trigger an irreversible cell-cycle arrest. We have examined the effect of suppressing the histone demethylases Jarid1a and Jarid1b on the senescence-associated gene expression signatures. Human fibroblast (IMR90) cells were infected with retroviral vectors expresssing shRNA targeting Jarid1a, Jarid1b or both, and triggered to undergo quiescence by removal of serum or senescence by over-expression of activated ras (Hrasv12).
Project description:Cellular senescence is a tumor-suppressive program that involves chromatin reorganization and specific changes in gene expression that trigger an irreversible cell-cycle arrest. We have examined the effect of suppressing the histone demethylases Jarid1a and Jarid1b on the senescence-associated gene expression signatures.
Project description:Aberrations in epigenetic processes, such as histone methylation, can lead to cancer. Retinoblastoma Binding Protein 2 (RBP2)(also called JARID1A or KDM5A) can demethylate tri- and di-methylated lysine 4 in histone H3, which are epigenetic marks for transcriptionally active chromatin, whereas the MEN1 tumor suppressor promotes H3K4 methylation. Previous studies suggested that inhibition of RBP2 contributed to tumor suppression by pRB. Here we show RBP2 loss promotes cellular differentiation in vitro. We use mouse expression array 430 2.0 array to profile gene expression patterns of Rbp2f/f and Rbp2-/- ES cells in ES cell medium and after 6 days in ES cell medium without LIF.
Project description:Histone H3 lysine-9 methylation (H3K9me) is essential for retinoblastoma protein (RB)-mediated heterochromatin formation, epigenetic silencing of S-phase genes and permanent cell cycle arrest or cellular senescence. Besides as an H3K4me demethylase, lysine-specific demethylase 1 (LSD1) has also been shown to promote H3K9 demethylation. However, it is unclear whether LSD1 plays any roles in regulating cell cycle entry and senescence. Here we demonstrate that genetic depletion or pharmacological inhibition of LSD1 triggers G1 arrest and cellular senescence. Genome-wide chromatin immunoprecipitation-sequencing (ChIP-seq) analysis reveal that the binding sites of LSD1 significantly overlaps with those bound by the S-phase gene transcription factor E2F1. Gene ontology (GO) analysis demonstrates that a large portion of E2F1 and LSD1 co-targeted genes are involved in cell cycle and proliferation. Further analyses show that depletion of LSD1 not only inhibits expression of the LSD1-E2F1 co-target genes, but also decreases the level of H3K9me2, but not H3K4me2 in those loci. Furthermore, the enzymatic activity of LSD1 is essential for H3K9me2 demethylation at cell cycle gene loci. Notably, co-treatment of chemotherapeutic agent camptothecin (CPT) enhanced LSD1 inhibitor-induced senescence and growth inhibition of cancer cells in vitro and in mice. Our data reveal LSD1 as a molecular rheostat regulating selective H3K9 demethylation at cell cycle gene loci, thereby representing a key event in oncogenesis and a viable target for cancer therapy.
Project description:Histone H3K4 methylation has been linked to transcriptional activation. JARID1A (also known as RBP2 or KDM5A), a member of the JARID1 protein family, is an H3K4 demethylase, previously implicated in the regulation of transcription and differentiation. Here we show that JARID1A is physically and functionally associated with two histone deacetylase complexes. Immunoaffinity purification of JARID1A confirmed a previously described association with the SIN3B-containing HDAC complex, and revealed an association with the nucleosome remodeling and deacetylase (NuRD) complex. Sucrose density gradient and sequential immunoprecipitation analyses further confirmed the stable association of JARID1A with these two HDAC complexes. JARID1A depletion led to changes in the expression of hundreds of genes, two-thirds of which were also controlled by CHD4, the NuRD catalytic subunit. Gene ontology analysis confirmed that the genes commonly regulated by both JARID1A and CHD4 were categorized as developmentally regulated genes. ChIP analyses suggested that CHD4 controls chromatin association with JARID1A and modulates H3K4 levels at the promoter and coding regions of target genes. We further demonstrated that the C. elegans homologues of JARID1 and CHD4 function in the same pathway during vulva development. Taken together, these results suggest that JARID1A and the NuRD complex cooperatively function to control developmentally regulated genes.
Project description:Histone H3K4 methylation has been linked to transcriptional activation. JARID1A (also known as RBP2 or KDM5A), a member of the JARID1 protein family, is an H3K4 demethylase, previously implicated in the regulation of transcription and differentiation. Here we show that JARID1A is physically and functionally associated with two histone deacetylase complexes. Immunoaffinity purification of JARID1A confirmed a previously described association with the SIN3B-containing HDAC complex, and revealed an association with the nucleosome remodeling and deacetylase (NuRD) complex. Sucrose density gradient and sequential immunoprecipitation analyses further confirmed the stable association of JARID1A with these two HDAC complexes. JARID1A depletion led to changes in the expression of hundreds of genes, two-thirds of which were also controlled by CHD4, the NuRD catalytic subunit. Gene ontology analysis confirmed that the genes commonly regulated by both JARID1A and CHD4 were categorized as developmentally regulated genes. ChIP analyses suggested that CHD4 controls chromatin association with JARID1A and modulates H3K4 levels at the promoter and coding regions of target genes. We further demonstrated that the C. elegans homologues of JARID1 and CHD4 function in the same pathway during vulva development. Taken together, these results suggest that JARID1A and the NuRD complex cooperatively function to control developmentally regulated genes. Genome-wide transcriptomic analysis of HeLa cells transfected with JARID1A complex component siRNA
Project description:Aberrations in epigenetic processes, such as histone methylation, can lead to cancer. Retinoblastoma Binding Protein 2 (RBP2)(also called JARID1A or KDM5A) can demethylate tri- and di-methylated lysine 4 in histone H3, which are epigenetic marks for transcriptionally active chromatin, whereas the MEN1 tumor suppressor promotes H3K4 methylation. Previous studies suggested that inhibition of RBP2 contributed to tumor suppression by pRB. Here we show RBP2 loss promotes cellular differentiation in vitro. We use mouse expression array 430 2.0 array to profile gene expression patterns of Rbp2f/f and Rbp2-/- ES cells in ES cell medium and after 6 days in ES cell medium without LIF. Subconfluent Rbp2f/f and Rbp2-/- ES cells in ES cell medium and after 6 days in ES cell medium without LIF were harvested for RNA isolation using RNeasy mini kit with on-column DNase digestion (Qiagen). Gene expression profiling was performed using Affymetrix GeneChip mouse genome 430 2.0 arrays. Duplicate samples were used
Project description:The jmjC-domain containing H3K4 histone demethylase JARID1B/KDM5B/PLU1 is over-expressed in human breast cancer and is a potential target for breast cancer treatment. To investigate the in vivo function of JARID1B, we developed a new strain of Jarid1b knockout mice and characterized the phenotypes in detail. Unlike previously reported knockout strains, the majority of our Jarid1b knockout mice are viable beyond embryonic and neonatal stages. Nonetheless, these mice exhibit decreased body weight, higher incidence of adult mortality and decreased female fertility. Furthermore, Jarid1b knockout mice show delayed mammary gland development. Mechanistically, loss of JARID1B leads to decreased serum estrogen levels and reduced proliferation of mammary epithelial cells in early puberty. In addition, in mammary epithelial cells, loss of JARID1B diminishes the expression of key regulators of mammary morphogenesis, including FOXA1, estrogen receptor α (ERα), and GATA3. Taken together, these results indicate that JARID1B positively regulates mammary ductal development through both extrinsic and cell-autonomous mechanisms.