Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites. Genome-wide expression profiling of HT1080 cells stably transduced with ING2 or a ING2 lipid binding mutant in the presence of vehicle (DMSO) or etoposide. Each condition is tested in triplicate
Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites. FLAG-ING2 ChIP-chip of stably-transduced HT1080 cells in the presence of vehicle (DMSO) or etoposide. Each condition is tested in duplicate.
Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites.
Project description:ING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites.
Project description:Nuclear phosphatidylinositol-5-phosphate regulates ING2 stability at discrete chromatin targets in response to DNA damage [ChIP-chip]
Project description:Nuclear myosin 1 (NM1) has been implicated in key nuclear functions. Here, we show NM1 has a global role in chromatin regulation and this likely impacts global transcription. High-content phenotypic profiling and transcriptional profiling by RNA-Seq on NM1 KO mouse embryonic fibroblasts show extensive chromatin alteration and differential gene expression compared to a WT condition. In particular, NM1 deletion leads to significant upregulation of genes involved in DNA damage response and cell cycle, which is further supported by increased DNA damage revealed by increased γ-H2AX foci number and proliferation rate. We found that upon DNA damage, NM1 directly regulates expression of Cdkn1A (p21) and binds to p53. NM1 recruits histone acetyl-transferase PCAF and histone methyl-transferase Set1 to p21 promoter for histone H3 acetylation and methylation, facilitating Cdkn1A gene transcription. We propose that NM1 regulates the transcriptional response upon DNA damage and imply an involvement for NM1 in genome stability.
Project description:Expression profiling of mouse ing2 -/- testis vs WT reveals gene expression differences consistent with spermatogenic arrest and infertility. Ing2 is indispensable for male germ cell development in mice. While mice deficient for Ing2 were born and grew without apparent abnormalities, male, but not female, were infertile, consistent with the highest expression of Ing2 in testes in wild-type mice and in humans. Histological and DNA content analyses in Ing2-/- testes revealed a spermatogenesis arrest at meiotic phase and enhanced apoptosis associated with increased p53, resulting in a decline in mature spermatozoa, which became more severe in older age. HDAC1 accumulation and core histone deacetylation at pachytene stage were impaired in Ing2-/- testes, suggesting that the recruitment of HDAC1 by Ing2 plays a critical role in spermatogenesis. This study establishes Ing2 as a novel mammalian regulator of spermatocyte differentiation, which coordinates spermatogenesis stage-specific histone modifications. This study has implications in understanding human male infertility.
Project description:We report Illumina next generation RNA sequencing (RNAseq) of MLL-AF9 in vitro transformed murine LSKs upon genetic deletion of Mof. These gene expression data illustrate that Mof regulates the expression of genes involved in DNA damage response and chromatin stability in MLL-AF9 transformed cells.
Project description:ATP-dependent chromatin remodeling complexes have been shown to participate in DNA replication in addition to transcription and DNA repair. However, the mechanisms of their involvement in DNA replication remain unclear. Here, we reveal a specific function of the yeast INO80 chromatin remodeling complex in the DNA damage tolerance pathways. Whereas INO80 is necessary for the resumption of replication at forks stalled by methyl methane sulfonate (MMS), it is not required for replication fork collapse after treatment with hydroxyurea (HU). Mechanistically, INO80 regulates DNA damage tolerance during replication through modulation of PCNA (proliferating cell nuclear antigen) ubiquitination and Rad51-mediated processing of recombination intermediates at impeded replication forks. Our findings establish a mechanistic link between INO80 and DNA damage tolerance pathways, indicating that chromatin remodeling is important for accurate DNA replication. INO80 distribution in WT cells was measured.