Importance of Transcriptional coactivator PC4 in p53-dependent Genotoxic Stress Response
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PROVIDER: PRJNA476802 | ENA |
REPOSITORIES: ENA
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Project description:In order to get an idea of involvement of PC4 in regulation of p53-dependent gene expression, we carried out global gene expression profiling upon treatment with R6-NLS-p53(380–386-3Ac). R6-NLS-p53(380–386-3Ac) is a small peptide of 20 residues derived from p53 C-terminal domain. This peptide can successfully block the cellular p53-PC4 interactions. Lung cancer line A549 which contain both wild type p53 and PC4 were used for this study. The cells were treated with 25µM R6-NLS-p53(380–386-3Ac) for two different time points (12 h and 24 h) and the gene expression profile was analyzed by microarray analysis.
2019-06-21 | GSE116020 | GEO
Project description:Chromatin protein positive coactivator 4 (PC4) has multiple functions, including chromatin compaction. However, its role in immune cells is largely unknown. We show that PC4 orchestrates chromatin structure and gene expression in mature B cells. B-cell specific PC4-deficient mice showed impaired production of antibody upon antigen stimulation. The PC4 complex purified from B cells contained transcription factors IKAROS and IRF4. IKAROS protein was reduced in PC4-deficient mature B cells, resulting in de-repression of their target genes in part by diminished interactions with gene silencing components. Upon activation, IRF4 protein amount was not increased in PC4-deficient B cells, resulting in reduction of plasma cells. Importantly, IRF4 reciprocally induced PC4 expression via a super-enhancer. PC4 knockdown in human B-cell lymphoma cells reduced IKAROS protein as an anticancer drug lenalidomide. Our findings establish PC4 as a chromatin regulator of B cells and a possible therapeutic target adjoining IKAROS in B-cell malignancies.
2020-12-22 | GSE163216 | GEO
Project description:B cell development is orchestrated by various transcription factors collaborating with chromatin remodelers that determine the genomic architecture. However, chromatin regulation in mature B cells is still poorly understood. Here, we show the critical function of positive coactivator 4 (PC4), a bona fide non-histone chromatin protein encoded by Sub1. B-cell specific Sub1-deficient mice showed the decreased number and response against antigen stimulation of mature B cells. By combining PC4 chromatin immunoprecipitation-sequencing and complex purification, we identified transcription factor IKAROS as a partner of PC4 in gene regulation. PC4 and IKAROS cooperated to promote heterochromatin formation of their target gene loci and thereby established B cell identity. Importantly, PC4 stabilized IKAROS protein in mature B cells and inhibited IKAROS degradation by the anti-cancer drug lenalidomide in human B-cell lymphoma cells. These findings establish PC4 as not only a chromatin regulator of B cells but also a new therapeutic target in B-cell malignancies.
2020-12-22 | GSE145952 | GEO
Project description:B cell development is orchestrated by various transcription factors collaborating with chromatin remodelers that determine the genomic architecture. However, chromatin regulation in mature B cells is still poorly understood. Here, we show the critical function of positive coactivator 4 (PC4), a bona fide non-histone chromatin protein encoded by Sub1. B-cell specific Sub1-deficient mice showed the decreased number and response against antigen stimulation of mature B cells. By combining PC4 chromatin immunoprecipitation-sequencing and complex purification, we identified transcription factor IKAROS as a partner of PC4 in gene regulation. PC4 and IKAROS cooperated to promote heterochromatin formation of their target gene loci and thereby established B cell identity. Importantly, PC4 stabilized IKAROS protein in mature B cells and inhibited IKAROS degradation by the anti-cancer drug lenalidomide in human B-cell lymphoma cells. These findings establish PC4 as not only a chromatin regulator of B cells but also a new therapeutic target in B-cell malignancies.
2020-12-22 | GSE145951 | GEO
Project description:To assess the mechanisms by which PC4 mediates chromatin compaction in cells and regulation of genome organization by its phosphorylation state, we measured the chromatin accessibility landscape using ATAC-seq of vector control 293 cells (Control/shNS), PC4 knockdown (KD/PC4 KD) and upon ectopic expression of Flag tagged PC4 (FP/PC4), Phosphomimic-PC4 (PM/PM-PC4) and phospho-mutant (MTP/MTP5) in PC4 knockdown cells.
2022-05-12 | GSE191333 | GEO
Project description:Human positive coactivator 4 (PC4), is a highly abundant non-histone chromatin protein involved in diverse cellular processes, including transcription regulation, genome organization, autophagy, B-cell differentiation, neurogenesis, DNA repair, etc. Most PC4 is phosphorylated in cells, which interacts with core histones and the linker histone H1 to confer the compact heterochromatin state of the genome. Knocking down of PC4 at both cellular and organismal levels leads to significant chromatin decondensation, altered epigenetic landscape, enhanced autophagy, and increased DNA damage susceptibility. Here, we report that besides p300, PC4 also gets acetylated by DNA repair, facilitating lysine acetyltransferase KAT5 (Tip60) at a specific lysine residue (PC4K80) when the cells are subjected to DNA damage. The vulnerability of DNA in PC4 devoid cells was substantially reduced by reintroducing wild-type PC4 to the cells but not the mutant PC4 (PC4K80R), defective in KAT5-mediated acetylation. High-resolution microscopy techniques, including transmission electron microscopy (TEM) and atomic force microscopy (AFM), are employed to visualize chromatin structural changes in response to DNA damage and repair in a Tip60- mediated PC4 acetylation-dependent manner. Presumably, KAT5-mediated acetylation of PC4 at K80 residue facilitates access to the damaged DNA by altering chromatin structures at damage sites, thus promoting DNA repair. This process could be highly significant both in cancer and in aging.
2025-10-20 | PXD059878 | Pride
Project description:Human positive coactivator 4 (PC4), is a highly abundant non-histone chromatin protein involved in diverse cellular processes, including transcription regulation, genome organization, autophagy, B-cell differentiation, neurogenesis, DNA repair, etc. Most PC4 is phosphorylated in cells, which interacts with core histones and the linker histone H1 to confer the compact heterochromatin state of the genome. Knocking down of PC4 at both cellular and organismal levels leads to significant chromatin decondensation, altered epigenetic landscape, enhanced autophagy, and increased DNA damage susceptibility. Here, we report that besides p300, PC4 also gets acetylated by DNA repair, facilitating lysine acetyltransferase KAT5 (Tip60) at a specific lysine residue (PC4K80) when the cells are subjected to DNA damage. The vulnerability of DNA in PC4 devoid cells was substantially reduced by reintroducing wild-type PC4 to the cells but not the mutant PC4 (PC4K80R), defective in KAT5-mediated acetylation. High-resolution microscopy techniques, including transmission electron microscopy (TEM) and atomic force microscopy (AFM), are employed to visualize chromatin structural changes in response to DNA damage and repair in a Tip60- mediated PC4 acetylation-dependent manner. Presumably, KAT5-mediated acetylation of PC4 at K80 residue facilitates access to the damaged DNA by altering chromatin structures at damage sites, thus promoting DNA repair. This process could be highly significant both in cancer and in aging
2025-10-20 | PXD058855 | Pride
Project description:Stem and progenitor cells are the main mediators of tissue renewal and repair, both under homeostatic conditions and in the response to physiological stress and injury. Hematopoietic system is responsible for the regeneration of blood and immune cells, and is maintained by bone marrow resident hematopoietic stem and progenitor cells (HSPCs). Hematopoietic system is particularly susceptible to injury in response to genotoxic stress, resulting in risk of bone marrow failure and secondary malignancies in cancer patients undergoing radiotherapy. Here we analyze the in vivo transcriptional response of HSPCs to genotoxic stress in a mouse whole body irradiation model, and together with p53 ChIP-Seq and studies in p53-knockout (p53KO) mice, characterize the p53-dependent and p53-independent branches of this transcriptional response. Our work demonstrates the p53-independent induction of inflammatory transcriptional signatures in HSPCs in response to genotoxic stress, and identifies multiple novel p53-target genes induced in HSPCs in response to whole body irradiation. In particular, we establish the direct p53-mediated induction of P2X7 expression on HSCs and HSPCs in response to genotoxic stress. We further demonstrate the role of P2X7 in hematopoietic response to acute genotoxic stress, with P2X7-deficiency significantly extending mouse survival in irradiation-induced hematopoietic failure. We also demonstrate the role of P2X7 in the context of long-term HSC regenerative fitness following sublethal irradiation. Overall our studies provide important insights into the mechanisms of HSC response to genotoxic stress and further suggests P2X7 as a target for pharmacological modulation of HSC fitness and hematopoietic response to genotoxic injury.
2021-10-09 | GSE171691 | GEO
Project description:Stem and progenitor cells are the main mediators of tissue renewal and repair, both under homeostatic conditions and in the response to physiological stress and injury. Hematopoietic system is responsible for the regeneration of blood and immune cells, and is maintained by bone marrow resident hematopoietic stem and progenitor cells (HSPCs). Hematopoietic system is particularly susceptible to injury in response to genotoxic stress, resulting in risk of bone marrow failure and secondary malignancies in cancer patients undergoing radiotherapy. Here we analyze the in vivo transcriptional response of HSPCs to genotoxic stress in a mouse whole body irradiation model, and together with p53 ChIP-Seq and studies in p53-knockout (p53KO) mice, characterize the p53-dependent and p53-independent branches of this transcriptional response. Our work demonstrates the p53-independent induction of inflammatory transcriptional signatures in HSPCs in response to genotoxic stress, and identifies multiple novel p53-target genes induced in HSPCs in response to whole body irradiation. In particular, we establish the direct p53-mediated induction of P2X7 expression on HSCs and HSPCs in response to genotoxic stress. We further demonstrate the role of P2X7 in hematopoietic response to acute genotoxic stress, with P2X7-deficiency significantly extending mouse survival in irradiation-induced hematopoietic failure. We also demonstrate the role of P2X7 in the context of long-term HSC regenerative fitness following sublethal irradiation. Overall our studies provide important insights into the mechanisms of HSC response to genotoxic stress and further suggests P2X7 as a target for pharmacological modulation of HSC fitness and hematopoietic response to genotoxic injury.
2021-10-09 | GSE171694 | GEO
Project description:Transcriptome analysis of polymorphic p53 codon 72 under genotoxic stress
| PRJNA761662 | ENA