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Ferruzo PYM, Boell VK, Russo LC, Oliveira CC, Forti FL. DUSP3 modulates IRES-dependent translation of mRNAs through dephosphorylation of the HNRNPC protein in cells under genotoxic stimulus. Biol Cell 2024; 116:e2300128. [PMID: 38538536 DOI: 10.1111/boc.202300128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/02/2024] [Accepted: 03/06/2024] [Indexed: 05/09/2024]
Abstract
BACKGROUND INFORMATION The dual-specificity phosphatase 3 (DUSP3) regulates cell cycle progression, proliferation, senescence, and DNA repair pathways under genotoxic stress. This phosphatase interacts with HNRNPC protein suggesting an involvement in the regulation of HNRNPC-ribonucleoprotein complex stability. In this work, we investigate the impact of DUSP3 depletion on functions of HNRNPC aiming to suggest new roles for this enzyme. RESULTS The DUSP3 knockdown results in the tyrosine hyperphosphorylation state of HNRNPC increasing its RNA binding ability. HNRNPC is present in the cytoplasm where it interacts with IRES trans-acting factors (ITAF) complex, which recruits the 40S ribosome on mRNA during protein synthesis, thus facilitating the translation of mRNAs containing IRES sequence in response to specific stimuli. In accordance with that, we found that DUSP3 is present in the 40S, monosomes and polysomes interacting with HNRNPC, just like other previously identified DUSP3 substrates/interacting partners such as PABP and NCL proteins. By downregulating DUSP3, Tyr-phosphorylated HNRNPC preferentially binds to IRES-containing mRNAs within ITAF complexes preferentially in synchronized or stressed cells, as evidenced by the higher levels of proteins such as c-MYC and XIAP, but not their mRNAs such as measured by qPCR. Under DUSP3 absence, this increased phosphorylated-HNRNPC/RNA interaction reduces HNRNPC-p53 binding in presence of RNAs releasing p53 for specialized cellular responses. Similarly, to HNRNPC, PABP physically interacts with DUSP3 in an RNA-dependent manner. CONCLUSIONS AND SIGNIFICANCE Overall, DUSP3 can modulate cellular responses to genotoxic stimuli at the translational level by maintaining the stability of HNRNPC-ITAF complexes and regulating the intensity and specificity of RNA interactions with RRM-domain proteins.
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Affiliation(s)
- Pault Y M Ferruzo
- Laboratory of Signaling in Biomolecular Systems, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Viktor K Boell
- Laboratory of Signaling in Biomolecular Systems, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Lilian C Russo
- Laboratory of Genome Instability, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Carla C Oliveira
- Laboratory of Post-transcriptional Control of Gene Expression, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Fabio L Forti
- Laboratory of Signaling in Biomolecular Systems, Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
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2
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Muhammad T, Pastore SF, Good K, Ausió J, Vincent JB. Chromatin gatekeeper and modifier CHD proteins in development, and in autism and other neurological disorders. Psychiatr Genet 2023; 33:213-232. [PMID: 37851134 DOI: 10.1097/ypg.0000000000000353] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Chromatin, a protein-DNA complex, is a dynamic structure that stores genetic information within the nucleus and responds to molecular/cellular changes in its structure, providing conditional access to the genetic machinery. ATP-dependent chromatin modifiers regulate access of transcription factors and RNA polymerases to DNA by either "opening" or "closing" the structure of chromatin, and its aberrant regulation leads to a variety of neurodevelopmental disorders. The chromodomain helicase DNA-binding (CHD) proteins are ATP-dependent chromatin modifiers involved in the organization of chromatin structure, act as gatekeepers of genomic access, and deposit histone variants required for gene regulation. In this review, we first discuss the structural and functional domains of the CHD proteins, and their binding sites, and phosphorylation, acetylation, and methylation sites. The conservation of important amino acids in SWItch/sucrose non-fermenting (SWI/SNF) domains, and their protein and mRNA tissue expression profiles are discussed. Next, we convey the important binding partners of CHD proteins, their protein complexes and activities, and their involvements in epigenetic regulation. We also show the ChIP-seq binding dynamics for CHD1, CHD2, CHD4, and CHD7 proteins at promoter regions of histone genes, as well as several genes that are critical for neurodevelopment. The role of CHD proteins in development is also discussed. Finally, this review provides information about CHD protein mutations reported in autism and neurodevelopmental disorders, and their pathogenicity. Overall, this review provides information on the progress of research into CHD proteins, their structural and functional domains, epigenetics, and their role in stem cell, development, and neurological disorders.
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Affiliation(s)
- Tahir Muhammad
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Institute of Medical Science, University of Toronto, Toronto, ON
| | - Stephen F Pastore
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Institute of Medical Science, University of Toronto, Toronto, ON
| | - Katrina Good
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC
| | - John B Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Institute of Medical Science, University of Toronto, Toronto, ON
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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3
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Role of Heterogeneous Nuclear Ribonucleoproteins in the Cancer-Immune Landscape. Int J Mol Sci 2023; 24:ijms24065086. [PMID: 36982162 PMCID: PMC10049280 DOI: 10.3390/ijms24065086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/09/2023] Open
Abstract
Cancer remains the second leading cause of death, accounting for approximately 20% of all fatalities. Evolving cancer cells and a dysregulated immune system create complex tumor environments that fuel tumor growth, metastasis, and resistance. Over the past decades, significant progress in deciphering cancer cell behavior and recognizing the immune system as a hallmark of tumorigenesis has been achieved. However, the underlying mechanisms controlling the evolving cancer-immune landscape remain mostly unexplored. Heterogeneous nuclear ribonuclear proteins (hnRNP), a highly conserved family of RNA-binding proteins, have vital roles in critical cellular processes, including transcription, post-transcriptional modifications, and translation. Dysregulation of hnRNP is a critical contributor to cancer development and resistance. HnRNP contribute to the diversity of tumor and immune-associated aberrant proteomes by controlling alternative splicing and translation. They can also promote cancer-associated gene expression by regulating transcription factors, binding to DNA directly, or promoting chromatin remodeling. HnRNP are emerging as newly recognized mRNA readers. Here, we review the roles of hnRNP as regulators of the cancer-immune landscape. Dissecting the molecular functions of hnRNP will provide a better understanding of cancer-immune biology and will impact the development of new approaches to control and treat cancer.
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4
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Wang S, C Ordonez-Rubiano S, Dhiman A, Jiao G, Strohmier BP, Krusemark CJ, Dykhuizen EC. Polycomb group proteins in cancer: multifaceted functions and strategies for modulation. NAR Cancer 2021; 3:zcab039. [PMID: 34617019 PMCID: PMC8489530 DOI: 10.1093/narcan/zcab039] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/24/2021] [Accepted: 09/10/2021] [Indexed: 12/12/2022] Open
Abstract
Polycomb repressive complexes (PRCs) are a heterogenous collection of dozens, if not hundreds, of protein complexes composed of various combinations of subunits. PRCs are transcriptional repressors important for cell-type specificity during development, and as such, are commonly mis-regulated in cancer. PRCs are broadly characterized as PRC1 with histone ubiquitin ligase activity, or PRC2 with histone methyltransferase activity; however, the mechanism by which individual PRCs, particularly the highly diverse set of PRC1s, alter gene expression has not always been clear. Here we review the current understanding of how PRCs act, both individually and together, to establish and maintain gene repression, the biochemical contribution of individual PRC subunits, the mis-regulation of PRC function in different cancers, and the current strategies for modulating PRC activity. Increased mechanistic understanding of PRC function, as well as cancer-specific roles for individual PRC subunits, will uncover better targets and strategies for cancer therapies.
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Affiliation(s)
- Sijie Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University and Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907 USA
| | - Sandra C Ordonez-Rubiano
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University and Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907 USA
| | - Alisha Dhiman
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University and Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907 USA
| | - Guanming Jiao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University and Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907 USA
| | - Brayden P Strohmier
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University and Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907 USA
| | - Casey J Krusemark
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University and Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907 USA
| | - Emily C Dykhuizen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University and Purdue University Center for Cancer Research, 201 S. University St., West Lafayette, IN 47907 USA
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5
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Zhang M, Sun Y, Huang CP, Luo J, Zhang L, Meng J, Liang C, Chang C. Targeting the Lnc-OPHN1-5/androgen receptor/hnRNPA1 complex increases Enzalutamide sensitivity to better suppress prostate cancer progression. Cell Death Dis 2021; 12:855. [PMID: 34545067 PMCID: PMC8452728 DOI: 10.1038/s41419-021-03966-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 06/14/2021] [Accepted: 06/21/2021] [Indexed: 12/14/2022]
Abstract
Long non-coding RNAs (lncRNAs) have been found to play critical roles in regulating gene expression, but their function in translational control is poorly understood. We found lnc-OPHN1-5, which lies close to the androgen receptor (AR) gene on chromosome X, increased prostate cancer (PCa) Enzalutamide (Enz) sensitivity via decreasing AR protein expression and associated activity. Mechanism dissection revealed that lnc-OPHN1-5 interacted with AR-mRNA to minimize its interaction with the RNA binding protein (RBP) hnRNPA1. Suppressing lnc-OPHN1-5 expression promoted the interaction between AR-mRNA and hnRNPA1, followed by an increase of ribosome association with AR-mRNA and translation. This effect was reversed by increasing lnc-OPHN1-5 expression. Consistently, the in vivo mice model confirmed that knocking down lnc-OPHN1-5 expression in tumors significantly increased the tumor formation rate and AR protein expression compared with the control group. Furthermore, knocking down hnRNPA1 blocked/reversed shlnc-OPHN1-5-increased AR protein expression and re-sensitized cells to Enz treatment efficacy. Evidence from Enz-resistant cell lines, patient-derived xenograft (PDX) models, clinical samples, and a human PCa study accordantly suggested that patients with low expression of lnc-OPHN1-5 likely have unfavorable prognoses and probably are less sensitive to Enz treatment. In summary, targeting this newly identified lnc-OPHN1-5/AR/hnRNPA1 complex may help develop novel therapies to increase Enz treatment sensitivity for suppressing the PCa at an advanced stage.
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Affiliation(s)
- Meng Zhang
- Department of Urology, The First Affiliated Hospital of Anhui Medical University, Institute of Urology, & Anhui Province Key Laboratory of Genitourinary Diseases, Anhui Medical University, Hefei, China.,George Whipple Lab for Cancer Research, Departments of Pathology, Urology, Radiation Oncology, The Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA.,Institute of Urology, Shenzhen University, Shenzhen, China
| | - Yin Sun
- George Whipple Lab for Cancer Research, Departments of Pathology, Urology, Radiation Oncology, The Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Chi-Ping Huang
- Department of Urology, China Medical University, Taichung, Taiwan
| | - Jie Luo
- George Whipple Lab for Cancer Research, Departments of Pathology, Urology, Radiation Oncology, The Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Li Zhang
- Department of Urology, The First Affiliated Hospital of Anhui Medical University, Institute of Urology, & Anhui Province Key Laboratory of Genitourinary Diseases, Anhui Medical University, Hefei, China
| | - Jialin Meng
- Department of Urology, The First Affiliated Hospital of Anhui Medical University, Institute of Urology, & Anhui Province Key Laboratory of Genitourinary Diseases, Anhui Medical University, Hefei, China
| | - Chaozhao Liang
- Department of Urology, The First Affiliated Hospital of Anhui Medical University, Institute of Urology, & Anhui Province Key Laboratory of Genitourinary Diseases, Anhui Medical University, Hefei, China.
| | - Chawnshang Chang
- George Whipple Lab for Cancer Research, Departments of Pathology, Urology, Radiation Oncology, The Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA. .,Department of Urology, China Medical University, Taichung, Taiwan.
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6
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Jena SR, Nayak J, Kumar S, Kar S, Dixit A, Samanta L. Paternal contributors in recurrent pregnancy loss: Cues from comparative proteome profiling of seminal extracellular vesicles. Mol Reprod Dev 2020; 88:96-112. [PMID: 33345401 DOI: 10.1002/mrd.23445] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 11/04/2020] [Accepted: 12/03/2020] [Indexed: 12/22/2022]
Abstract
Recent evidence entail paternal factors as plausible contributors in spontaneous recurrent pregnancy loss (RPL). Seminal extracellular vesicles secreted from cells of male reproductive tract carry regulatory proteins and RNAs. They are proposed to regulate sperm maturation and function while their fusion to endometrial stromal cells helps in decidualization. Nevertheless, the mechanism(s) involved in these processes are poorly understood. This study aims at elucidating the molecular basis of paternal contribution by comparative proteomics (label-free LC-MS/MS) of isolated seminal extracellular vesicles from fertile men and partners of patients with RPL (n = 21 per group). Bioinformatics analysis revealed the identified differentially expressed proteins to be involved in DNA replication, recombination and repair, gene expression, cellular assembly and organization, cell death, and survival. Major disease pathways affected were identified as developmental, hereditary, and immunological disorders. Of the three identified hub genes regulating the above disease pathways, two (HNRNPC and HNRNPU) are overexpressed while RUVBL1 is underexpressed along with over expression of HIST1H1C, DDX1, surmising defective chromatin packaging, and histone removal in spermatozoa resulting in improper expression in paternal genes thereby leading to abnormal embryo development. Besides, alteration in GSTP1 expression points oxidative predominance in RPL group. Differential expression of C3, C4a/C4b, CFB, and GDF 15 may be involved in altered maternal immune response to paternal antigens resulting in impaired decidualization.
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Affiliation(s)
- Soumya R Jena
- Department of Zoology, Redox Biology Laboratory, School of Life Sciences, Ravenshaw University, Odisha, India.,Centre for Excellence in Environment and Public Health, Ravenshaw University, Odisha, India
| | - Jasmine Nayak
- Department of Zoology, Redox Biology Laboratory, School of Life Sciences, Ravenshaw University, Odisha, India.,Centre for Excellence in Environment and Public Health, Ravenshaw University, Odisha, India
| | - Sugandh Kumar
- Computational Biology and Bioinformatics Laboratory, Institute of Life Sciences, Bhubaneswar, Odisha, India
| | - Sujata Kar
- Department of Obstetrics & Gynaecology, Kar Clinic and Hospital Pvt. Ltd., Bhubaneswar, India
| | - Anshuman Dixit
- Computational Biology and Bioinformatics Laboratory, Institute of Life Sciences, Bhubaneswar, Odisha, India
| | - Luna Samanta
- Department of Zoology, Redox Biology Laboratory, School of Life Sciences, Ravenshaw University, Odisha, India.,Centre for Excellence in Environment and Public Health, Ravenshaw University, Odisha, India
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7
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Further delineation of the neurodevelopmental phenotypic spectrum associated to 14q11.2 microduplication. Neurol Sci 2020; 41:3751-3753. [DOI: 10.1007/s10072-020-04510-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/30/2020] [Indexed: 01/01/2023]
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8
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Lee CH, Shih YP, Ho MR, Wang AHJ. The C-terminal D/E-rich domain of MBD3 is a putative Z-DNA mimic that competes for Zα DNA-binding activity. Nucleic Acids Res 2019; 46:11806-11821. [PMID: 30304469 PMCID: PMC6294567 DOI: 10.1093/nar/gky933] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 10/04/2018] [Indexed: 12/25/2022] Open
Abstract
The Z-DNA binding domain (Zα), derived from the human RNA editing enzyme ADAR1, can induce and stabilize the Z-DNA conformation. However, the biological function of Zα/Z-DNA remains elusive. Herein, we sought to identify proteins associated with Zα to gain insight into the functional network of Zα/Z-DNA. By pull-down, biophysical and biochemical analyses, we identified a novel Zα-interacting protein, MBD3, and revealed that Zα interacted with its C-terminal acidic region, an aspartate (D)/glutamate (E)-rich domain, with high affinity. The D/E-rich domain of MBD3 may act as a DNA mimic to compete with Z-DNA for binding to Zα. Dimerization of MBD3 via intermolecular interaction of the D/E-rich domain and its N-terminal DNA binding domain, a methyl-CpG-binding domain (MBD), attenuated the high affinity interaction of Zα and the D/E-rich domain. By monitoring the conformation transition of DNA, we found that Zα could compete with the MBD domain for binding to the Z-DNA forming sequence, but not vice versa. Furthermore, co-immunoprecipitation experiments confirmed the interaction of MBD3 and ADAR1 in vivo. Our findings suggest that the interplay of Zα and MBD3 may regulate the transition of the DNA conformation between B- and Z-DNA and thereby modulate chromatin accessibility, resulting in alterations in gene expression.
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Affiliation(s)
- Chi-Hua Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Yan-Ping Shih
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Meng-Ru Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Andrew H-J Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
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9
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10
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Ludwig AK, Zhang P, Cardoso MC. Modifiers and Readers of DNA Modifications and Their Impact on Genome Structure, Expression, and Stability in Disease. Front Genet 2016; 7:115. [PMID: 27446199 PMCID: PMC4914596 DOI: 10.3389/fgene.2016.00115] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/06/2016] [Indexed: 12/16/2022] Open
Abstract
Cytosine base modifications in mammals underwent a recent expansion with the addition of several naturally occurring further modifications of methylcytosine in the last years. This expansion was accompanied by the identification of the respective enzymes and proteins reading and translating the different modifications into chromatin higher order organization as well as genome activity and stability, leading to the hypothesis of a cytosine code. Here, we summarize the current state-of-the-art on DNA modifications, the enzyme families setting the cytosine modifications and the protein families reading and translating the different modifications with emphasis on the mouse protein homologs. Throughout this review, we focus on functional and mechanistic studies performed on mammalian cells, corresponding mouse models and associated human diseases.
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Affiliation(s)
- Anne K Ludwig
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
| | - Peng Zhang
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
| | - M C Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
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11
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Wang B, Sun J, Shi J, Guo Q, Tong X, Zhang J, Hu N, Hu Y. Small-Activating RNA Can Change Nucleosome Positioning in Human Fibroblasts. ACTA ACUST UNITED AC 2016; 21:634-42. [PMID: 26993320 DOI: 10.1177/1087057116637562] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 02/15/2016] [Indexed: 11/16/2022]
Abstract
RNA activation (RNAa) is a mechanism of positive gene expression regulation mediated by small-activating RNAs (saRNAs), which target gene promoters and have been used as tools to manipulate gene expression. Studies have shown that RNAa is associated with epigenetic modifications at promoter regions; however, it is unclear whether these modifications are the cause or a consequence of RNAa. In this study, we examined changes in nucleosome repositioning and the involvement of RNA polymerase II (RNAPII) in this process. We screened saRNAs for OCT4 (POU5F1), SOX2, and NANOG, and identified several novel saRNAs. We found that nucleosome positioning was altered after saRNA treatment and that the formation of nucleosome-depleted regions (NDRs) contributed to RNAa at sites of RNAPII binding, such as the TATA box, CpG islands (CGIs), proximal enhancers, and proximal promoters. Moreover, RNAPII appeared to be bound specifically to NDRs. These results suggested that changes in nucleosome positions resulted from RNAa. We thus propose a hypothesis that targeting promoter regions using exogenous saRNAs can induce the formation of NDRs, exposing regulatory binding sites to recruit RNAPII, a key component of preinitiation complex, and leading to increased initiation of transcription.
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Affiliation(s)
- Bin Wang
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China Department of Biology, Kunming University, Kunming, China
| | - Jing Sun
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China
| | - Jiandong Shi
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China
| | - Qing Guo
- Department of Biology, Kunming University, Kunming, China
| | - Xiangrong Tong
- Department of Biology, Kunming University, Kunming, China
| | - Jin Zhang
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China
| | - Ningzhu Hu
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China
| | - YunZhang Hu
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China
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12
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Nichol JN, Galbraith MD, Kleinman CL, Espinosa JM, Miller WH. NPM and BRG1 Mediate Transcriptional Resistance to Retinoic Acid in Acute Promyelocytic Leukemia. Cell Rep 2016; 14:2938-49. [PMID: 26997274 DOI: 10.1016/j.celrep.2016.02.074] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 12/16/2015] [Accepted: 02/17/2016] [Indexed: 11/19/2022] Open
Abstract
Perturbation in the transcriptional control of genes driving differentiation is an established paradigm whereby oncogenic fusion proteins promote leukemia. From a retinoic acid (RA)-sensitive acute promyelocytic leukemia (APL) cell line, we derived an RA-resistant clone characterized by a block in transcription initiation, despite maintaining wild-type PML/RARA expression. We uncovered an aberrant interaction among PML/RARA, nucleophosmin (NPM), and topoisomerase II beta (TOP2B). Surprisingly, RA stimulation in these cells results in enhanced chromatin association of the nucleosome remodeler BRG1. Inhibition of NPM or TOP2B abrogated BRG1 recruitment. Furthermore, NPM inhibition and targeting BRG1 restored differentiation when combined with RA. Here, we demonstrate a role for NPM and BRG1 in obstructing RA differentiation and implicate chromatin remodeling in mediating therapeutic resistance in malignancies. NPM mutations are the most common genetic change in patients with acute leukemia (AML); therefore, our model may be applicable to other more common leukemias driven by NPM.
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Affiliation(s)
- Jessica N Nichol
- Division of Experimental Medicine, Department of Oncology, Segal Cancer Centre and Lady Davis Institute, Jewish General Hospital, McGill University, Montréal, QC H3T 1E2, Canada
| | - Matthew D Galbraith
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Molecular, Cellular, and Developmental Biology and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Claudia L Kleinman
- Department of Human Genetics, Segal Cancer Centre and Lady Davis Institute, Jewish General Hospital, McGill University, Montréal, QC H3T 1E2, Canada
| | - Joaquín M Espinosa
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Molecular, Cellular, and Developmental Biology and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80309, USA; Linda Crnic Institute for Down Syndrome, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Wilson H Miller
- Division of Experimental Medicine, Department of Oncology, Segal Cancer Centre and Lady Davis Institute, Jewish General Hospital, McGill University, Montréal, QC H3T 1E2, Canada.
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13
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Naftelberg S, Schor IE, Ast G, Kornblihtt AR. Regulation of alternative splicing through coupling with transcription and chromatin structure. Annu Rev Biochem 2015; 84:165-98. [PMID: 26034889 DOI: 10.1146/annurev-biochem-060614-034242] [Citation(s) in RCA: 298] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alternative precursor messenger RNA (pre-mRNA) splicing plays a pivotal role in the flow of genetic information from DNA to proteins by expanding the coding capacity of genomes. Regulation of alternative splicing is as important as regulation of transcription to determine cell- and tissue-specific features, normal cell functioning, and responses of eukaryotic cells to external cues. Its importance is confirmed by the evolutionary conservation and diversification of alternative splicing and the fact that its deregulation causes hereditary disease and cancer. This review discusses the multiple layers of cotranscriptional regulation of alternative splicing in which chromatin structure, DNA methylation, histone marks, and nucleosome positioning play a fundamental role in providing a dynamic scaffold for interactions between the splicing and transcription machineries. We focus on evidence for how the kinetics of RNA polymerase II (RNAPII) elongation and the recruitment of splicing factors and adaptor proteins to chromatin components act in coordination to regulate alternative splicing.
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Affiliation(s)
- Shiran Naftelberg
- Sackler Medical School, Tel Aviv University, Tel Aviv 69978, Israel;
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14
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Shkreta L, Chabot B. The RNA Splicing Response to DNA Damage. Biomolecules 2015; 5:2935-77. [PMID: 26529031 PMCID: PMC4693264 DOI: 10.3390/biom5042935] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/20/2015] [Accepted: 10/16/2015] [Indexed: 12/29/2022] Open
Abstract
The number of factors known to participate in the DNA damage response (DDR) has expanded considerably in recent years to include splicing and alternative splicing factors. While the binding of splicing proteins and ribonucleoprotein complexes to nascent transcripts prevents genomic instability by deterring the formation of RNA/DNA duplexes, splicing factors are also recruited to, or removed from, sites of DNA damage. The first steps of the DDR promote the post-translational modification of splicing factors to affect their localization and activity, while more downstream DDR events alter their expression. Although descriptions of molecular mechanisms remain limited, an emerging trend is that DNA damage disrupts the coupling of constitutive and alternative splicing with the transcription of genes involved in DNA repair, cell-cycle control and apoptosis. A better understanding of how changes in splice site selection are integrated into the DDR may provide new avenues to combat cancer and delay aging.
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Affiliation(s)
- Lulzim Shkreta
- Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
| | - Benoit Chabot
- Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
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15
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The SWI/SNF chromatin remodeling complex regulates germinal center formation by repressing Blimp-1 expression. Proc Natl Acad Sci U S A 2015; 112:E718-27. [PMID: 25646472 DOI: 10.1073/pnas.1418592112] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Germinal center (GC) reaction is crucial in adaptive immune responses. The formation of GC is coordinated by the expression of specific genes including Blimp-1 and Bcl-6. Although gene expression is critically influenced by the status of chromatin structure, little is known about the role of chromatin remodeling factors for regulation of GC formation. Here, we show that the SWI/SNF chromatin remodeling complex is required for GC reactions. Mice lacking Srg3/mBaf155, a core component of the SWI/SNF complex, showed impaired differentiation of GC B and follicular helper T cells in response to T cell-dependent antigen challenge. The SWI/SNF complex regulates chromatin structure at the Blimp-1 locus and represses its expression by interacting cooperatively with Bcl-6 and corepressors. The defect in GC reactions in mice lacking Srg3 was due to the derepression of Blimp-1 as supported by genetic studies with Blimp-1-ablated mice. Hence, our study identifies the SWI/SNF complex as a key mediator in GC reactions by modulating Bcl-6-dependent Blimp-1 repression.
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16
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The heterodimeric structure of heterogeneous nuclear ribonucleoprotein C1/C2 dictates 1,25-dihydroxyvitamin D-directed transcriptional events in osteoblasts. Bone Res 2014; 2. [PMID: 25506471 PMCID: PMC4261231 DOI: 10.1038/boneres.2014.11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Heterogeneous nuclear ribonucleoprotein (hnRNP) C plays a key role in RNA processing but also exerts a dominant negative effect on responses to 1,25-dihydroxyvitamin D (1,25(OH)2D) by functioning as a vitamin D response element-binding protein (VDRE-BP). hnRNPC acts a tetramer of hnRNPC1 (huC1) and hnRNPC2 (huC2), and organization of these subunits is critical to in vivo nucleic acid-binding. Overexpression of either huC1 or huC2 in human osteoblasts is sufficient to confer VDRE-BP suppression of 1,25(OH)2D-mediated transcription. However, huC1 or huC2 alone did not suppress 1,25(OH)2D-induced transcription in mouse osteoblastic cells. By contrast, overexpression of huC1 and huC2 in combination or transfection with a bone-specific polycistronic vector using a “self-cleaving” 2A peptide to co-express huC1/C2 suppressed 1,25D-mediated induction of osteoblast target gene expression. Structural diversity of hnRNPC between human/NWPs and mouse/rat/rabbit/dog was investigated by analysis of sequence variations within the hnRNP CLZ domain. The predicted loss of distal helical function in hnRNPC from lower species provides an explanation for the altered interaction between huC1/C2 and their mouse counterparts. These data provide new evidence of a role for hnRNPC1/C2 in 1,25(OH)2D-driven gene expression, and further suggest that species-specific tetramerization is a crucial determinant of its actions as a regulator of VDR-directed transactivation.
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Emig-Agius D, Olivieri K, Pache L, Shih HL, Pustovalova O, Bessarabova M, Young JAT, Chanda SK, Ideker T. An integrated map of HIV-human protein complexes that facilitate viral infection. PLoS One 2014; 9:e96687. [PMID: 24817247 PMCID: PMC4016004 DOI: 10.1371/journal.pone.0096687] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 04/11/2014] [Indexed: 12/03/2022] Open
Abstract
Recent proteomic and genetic studies have aimed to identify a complete network of interactions between HIV and human proteins and genes. This HIV-human interaction network provides invaluable information as to how HIV exploits the host machinery and can be used as a starting point for further functional analyses. We integrated this network with complementary datasets of protein function and interaction to nominate human protein complexes with likely roles in viral infection. Based on our approach we identified a global map of 40 HIV-human protein complexes with putative roles in HIV infection, some of which are involved in DNA replication and repair, transcription, translation, and cytoskeletal regulation. Targeted RNAi screens were used to validate several proteins and complexes for functional impact on viral infection. Thus, our HIV-human protein complex map provides a significant resource of potential HIV-host interactions for further study.
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Affiliation(s)
- Dorothea Emig-Agius
- Departments of Medicine and Bioengineering, University of California at San Diego, La Jolla, California, United States of America
- IP&Science, Thomson Reuters Scientific Inc., Carlsbad, California, United States of America
| | - Kevin Olivieri
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Lars Pache
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Hsin Ling Shih
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Olga Pustovalova
- IP&Science, Thomson Reuters Scientific Inc., Carlsbad, California, United States of America
| | - Marina Bessarabova
- IP&Science, Thomson Reuters Scientific Inc., Carlsbad, California, United States of America
| | - John A. T. Young
- The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Sumit K. Chanda
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Trey Ideker
- Departments of Medicine and Bioengineering, University of California at San Diego, La Jolla, California, United States of America
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18
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Robinson JLL, Hickey TE, Warren AY, Vowler SL, Carroll T, Lamb AD, Papoutsoglou N, Neal DE, Tilley WD, Carroll JS. Elevated levels of FOXA1 facilitate androgen receptor chromatin binding resulting in a CRPC-like phenotype. Oncogene 2013; 33:5666-74. [PMID: 24292680 PMCID: PMC4051595 DOI: 10.1038/onc.2013.508] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 10/18/2013] [Accepted: 10/23/2013] [Indexed: 12/18/2022]
Abstract
Castration-resistant prostate cancer (CRPC) continues to pose a significant clinical challenge with new generation second line hormonal therapies affording limited improvement in disease outcome. As the androgen receptor (AR) remains a critical driver in CRPC, understanding the determinants of its transcriptional activity is important for developing new AR targeted therapies. FOXA1 is a key component of the AR transcriptional complex yet its role in prostate cancer progression and the relationship between AR and FOXA1 are not completely resolved. It is well established that FOXA1 levels are elevated in advanced prostate cancer and metastases. We mimicked these conditions by over-expressing FOXA1 in the androgen-responsive LNCaP prostate cancer cell line and observed a significant increase in AR genomic binding at novel regions that possess increased chromatin accessibility. High levels of FOXA1 resulted in increased proliferation at both sub-optimal and high 5α-dihydrotestosterone (DHT) concentrations. Immunohistochemical staining for FOXA1 in a clinical prostate cancer cohort revealed that high FOXA1 expression is associated with shorter time to biochemical recurrence after radical prostatectomy (HR 5.0, 95% CI 1.2-21.1, p=0.028), positive surgical margins and higher stage disease at diagnosis. The gene expression program that results from FOXA1 over-expression is enriched for PTEN, Wnt and other pathways typically represented in CRPC gene signatures. Together these results suggest that in an androgen-depleted state, elevated levels of FOXA1 enhance AR binding at genomic regions not normally occupied by AR, which in turn facilitates prostate cancer cell growth.
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Affiliation(s)
- J L L Robinson
- 1] Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK [2] Department of Oncology, University of Cambridge, Cambridge, UK
| | - T E Hickey
- Dame Roma Mitchell Cancer Research Laboratories and the Adelaide Prostate Cancer Research Centre, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - A Y Warren
- Department of Histopathology, Cambridge University Hospitals NHS Foundations Trust, Cambridge, UK
| | - S L Vowler
- 1] Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK [2] Department of Oncology, University of Cambridge, Cambridge, UK
| | - T Carroll
- 1] Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK [2] Department of Oncology, University of Cambridge, Cambridge, UK
| | - A D Lamb
- 1] Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK [2] Department of Oncology, University of Cambridge, Cambridge, UK [3] Department of Urology, Cambridge University Hospitals NHS Foundations Trust, Cambridge, UK
| | - N Papoutsoglou
- Department of Urology, Cambridge University Hospitals NHS Foundations Trust, Cambridge, UK
| | - D E Neal
- 1] Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK [2] Department of Oncology, University of Cambridge, Cambridge, UK [3] Dame Roma Mitchell Cancer Research Laboratories and the Adelaide Prostate Cancer Research Centre, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - W D Tilley
- Dame Roma Mitchell Cancer Research Laboratories and the Adelaide Prostate Cancer Research Centre, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - J S Carroll
- 1] Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK [2] Department of Oncology, University of Cambridge, Cambridge, UK
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Regulation of Gγ-globin gene by ATF2 and its associated proteins through the cAMP-response element. PLoS One 2013; 8:e78253. [PMID: 24223142 PMCID: PMC3819381 DOI: 10.1371/journal.pone.0078253] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/10/2013] [Indexed: 01/12/2023] Open
Abstract
The upstream Gγ-globin cAMP-response element (G-CRE) plays an important role in regulating Gγ-globin expression through binding of ATF2 and its DNA-binding partners defined in this study. ATF2 knockdown resulted in a significant reduction of γ-globin expression accompanied by decreased ATF2 binding to the G-CRE. By contrast, stable ATF2 expression in K562 cells increased γ-globin transcription which was reduced by ATF2 knockdown. Moreover, a similar effect of ATF2 on γ-globin expression was observed in primary erythroid progenitors. To understand the role of ATF2 in γ-globin expression, chromatographically purified G-CRE/ATF2-interacting proteins were subjected to mass spectrometry analysis; major binding partners included CREB1, cJun, Brg1, and histone deacetylases among others. Immunoprecipitation assays demonstrated interaction of these proteins with ATF2 and in vivo GCRE binding in CD34+ cells undergoing erythroid differentiation which was correlated with γ-globin expression during development. These results suggest synergism between developmental stage-specific recruitments of the ATF2 protein complex and expression of γ-globin during erythropoiesis. Microarray studies in K562 cells support ATF2 plays diverse roles in hematopoiesis and chromatin remodeling.
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20
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Pourfarzad F, Aghajanirefah A, de Boer E, Ten Have S, Bryn van Dijk T, Kheradmandkia S, Stadhouders R, Thongjuea S, Soler E, Gillemans N, von Lindern M, Demmers J, Philipsen S, Grosveld F. Locus-specific proteomics by TChP: targeted chromatin purification. Cell Rep 2013; 4:589-600. [PMID: 23911284 DOI: 10.1016/j.celrep.2013.07.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 07/01/2013] [Accepted: 07/07/2013] [Indexed: 12/20/2022] Open
Abstract
Here, we show that transcription factors bound to regulatory sequences can be identified by purifying these unique sequences directly from mammalian cells in vivo. Using targeted chromatin purification (TChP), a double-pull-down strategy with a tetracycline-sensitive "hook" bound to a specific promoter, we identify transcription factors bound to the repressed γ-globin gene-associated regulatory regions. After validation of the binding, we show that, in human primary erythroid cells, knockdown of a number of these transcription factors induces γ-globin gene expression. Reactivation of γ-globin gene expression ameliorates the symptoms of β-thalassemia and sickle cell disease, and these factors provide potential targets for the development of therapeutics for treating these patients.
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Affiliation(s)
- Farzin Pourfarzad
- Department of Cell Biology, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, the Netherlands; Center for Biomedical Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, the Netherlands
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21
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Functions of heterogeneous nuclear ribonucleoproteins in stem cell potency and differentiation. BIOMED RESEARCH INTERNATIONAL 2013; 2013:623978. [PMID: 23984388 PMCID: PMC3745930 DOI: 10.1155/2013/623978] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 12/26/2022]
Abstract
Stem cells possess huge importance in developmental biology, disease modelling, cell replacement therapy, and tissue engineering in regenerative medicine because they have the remarkable potential for self-renewal and to differentiate into almost all the cell types in the human body. Elucidation of molecular mechanisms regulating stem cell potency and differentiation is essential and critical for extensive application. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are modular proteins consisting of RNA-binding motifs and auxiliary domains characterized by extensive and divergent functions in nucleic acid metabolism. Multiple roles of hnRNPs in transcriptional and posttranscriptional regulation enable them to be effective gene expression regulators. More recent findings show that hnRNP proteins are crucial factors implicated in maintenance of stem cell self-renewal and pluripotency and cell differentiation. The hnRNPs interact with certain sequences in target gene promoter regions to initiate transcription. In addition, they recognize 3′UTR or 5′UTR of specific gene mRNA forming mRNP complex to regulate mRNA stability and translation. Both of these regulatory pathways lead to modulation of gene expression that is associated with stem cell proliferation, cell cycle control, pluripotency, and committed differentiation.
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22
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Use of biotinylated plasmid DNA as a surrogate for HSV DNA to identify proteins that repress or activate viral gene expression. Proc Natl Acad Sci U S A 2012; 109:E3549-57. [PMID: 23223531 DOI: 10.1073/pnas.1218783109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
ICP0, a key herpes simplex virus regulatory protein, functions first in the nucleus and then in the cytoplasm. The duration of its nuclear sojourn in cells transfected with DNA and then infected is related to the quantity of transfected DNA. Furthermore, ICP0 transactivates both viral genes and genes encoded by the transfected DNA. The data support the hypothesis that ICP0 is retained in the nucleus until it completes the replacement of repressive chromatin with effector proteins that enable transcription of both DNA templates.To identify the effector proteins, we transfected cells with biotinylated DNA encoding a nonviral gene and then infected the cells with wild-type virus. Proteins bound to transfected biotinylated plasmid recovered from mock-treated and infected cells were identified using mass spectrometry followed by appropriate database search. The transfected DNA from mock-infected cells yielded proteins associated with repression, whereas DNA recovered from infected cells included proteins known to enable transcription and proteins that have not been previously associated with that role. To test the hypothesis that the proteins hitherto not known to associate with viral gene expression are nevertheless essential, we tested the role of the DEAD-box helicase Ddx17. We report that Ddx17 plays a critical role in the expression of early and late viral genes. Thus, biotinylated DNA recovered from transfected infected cells can function as a surrogate for viral DNA and is a rich source of proteins that play a role in viral gene expression but which have not been previously identified in that role.
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23
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Yang T, Jian W, Luo Y, Fu X, Noguchi C, Bungert J, Huang S, Qiu Y. Acetylation of histone deacetylase 1 regulates NuRD corepressor complex activity. J Biol Chem 2012; 287:40279-91. [PMID: 23014989 DOI: 10.1074/jbc.m112.349704] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND HDAC1-containing NuRD complex is required for GATA-1-mediated repression and activation. RESULTS GATA-1 associated with acetylated HDAC1-containing NuRD complex, which has no deacetylase activity, for gene activation. CONCLUSION Acetylated HDAC1 converts NuRD complex from a repressor to an activator during GATA-1-directed erythroid differentiation program. SIGNIFICANCE HDAC1 acetylation may function as a master regulator for the activity of HDAC1 containing complexes. Histone deacetylases (HDACs) play important roles in regulating cell proliferation and differentiation. The HDAC1-containing NuRD complex is generally considered as a corepressor complex and is required for GATA-1-mediated repression. However, recent studies also show that the NuRD complex is involved in GATA-1-mediated gene activation. We tested whether the GATA-1-associated NuRD complex loses its deacetylase activity and commits the GATA-1 complex to become an activator during erythropoiesis. We found that GATA-1-associated deacetylase activity gradually decreased upon induction of erythroid differentiation. GATA-1-associated HDAC1 is increasingly acetylated after differentiation. It has been demonstrated earlier that acetylated HDAC1 has no deacetylase activity. Indeed, overexpression of an HDAC1 mutant, which mimics acetylated HDAC1, promotes GATA-1-mediated transcription and erythroid differentiation. Furthermore, during erythroid differentiation, acetylated HDAC1 recruitment is increased at GATA-1-activated genes, whereas it is significantly decreased at GATA-1-repressed genes. Interestingly, deacetylase activity is not required for Mi2 remodeling activity, suggesting that remodeling activity may be required for both activation and repression. Thus, our data suggest that NuRD can function as a coactivator or repressor and that acetylated HDAC1 converts the NuRD complex from a repressor to an activator during GATA-1-directed erythroid differentiation.
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Affiliation(s)
- Tao Yang
- Department of Anatomy and Cell Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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24
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Westmark CJ, Malter JS. The regulation of AβPP expression by RNA-binding proteins. Ageing Res Rev 2012; 11:450-9. [PMID: 22504584 DOI: 10.1016/j.arr.2012.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 03/13/2012] [Accepted: 03/28/2012] [Indexed: 12/29/2022]
Abstract
Amyloid β-protein precursor (AβPP) is cleaved by β- and γ-secretases to liberate amyloid beta (Aβ), the predominant protein found in the senile plaques associated with Alzheimer's disease (AD) and Down syndrome (Masters et al., 1985). Intense investigation by the scientific community has centered on understanding the molecular pathways that underlie the production and accumulation of Aβ Therapeutics that reduce the levels of this tenacious, plaque-promoting peptide may reduce the ongoing neural dysfunction and neuronal degeneration that occurs so profoundly in AD. AβPP and Aβ production are highly complex and involve still to be elucidated combinations of transcriptional, post-transcriptional, translational and post-translational events that mediate the production, processing and clearance of these proteins. Research in our laboratory for the past two decades has focused on the role of RNA binding proteins (RBPs) in mediating the post-transcriptional as well as translational regulation of APP messenger RNA (mRNA). This review article summarizes our findings, as well as those from other laboratories, describing the identification of regulatory RBPs, where and under what conditions they interact with APP mRNA and how those interactions control AβPP and Aβ synthesis.
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Affiliation(s)
- Cara J Westmark
- University of Wisconsin, Waisman Center for Developmental Disabilities, 1500 Highland Avenue, Madison, WI 53705, USA.
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25
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Yildirim O, Li R, Hung JH, Chen PB, Dong X, Ee LS, Weng Z, Rando OJ, Fazzio TG. Mbd3/NURD complex regulates expression of 5-hydroxymethylcytosine marked genes in embryonic stem cells. Cell 2012; 147:1498-510. [PMID: 22196727 DOI: 10.1016/j.cell.2011.11.054] [Citation(s) in RCA: 353] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 10/12/2011] [Accepted: 11/23/2011] [Indexed: 12/15/2022]
Abstract
Numerous chromatin regulators are required for embryonic stem (ES) cell self-renewal and pluripotency, but few have been studied in detail. Here, we examine the roles of several chromatin regulators whose loss affects the pluripotent state of ES cells. We find that Mbd3 and Brg1 antagonistically regulate a common set of genes by regulating promoter nucleosome occupancy. Furthermore, both Mbd3 and Brg1 play key roles in the biology of 5-hydroxymethylcytosine (5hmC): Mbd3 colocalizes with Tet1 and 5hmC in vivo, Mbd3 knockdown preferentially affects expression of 5hmC-marked genes, Mbd3 localization is Tet1-dependent, and Mbd3 preferentially binds to 5hmC relative to 5-methylcytosine in vitro. Finally, both Mbd3 and Brg1 are themselves required for normal levels of 5hmC in vivo. Together, our results identify an effector for 5hmC, and reveal that control of gene expression by antagonistic chromatin regulators is a surprisingly common regulatory strategy in ES cells.
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Affiliation(s)
- Ozlem Yildirim
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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26
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The chromatin backdrop of DNA replication: lessons from genetics and genome-scale analyses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:794-801. [PMID: 22342530 DOI: 10.1016/j.bbagrm.2012.01.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/27/2012] [Accepted: 01/31/2012] [Indexed: 01/04/2023]
Abstract
The entire cellular genome must replicate during each cell cycle, but it is yet unclear how replication proceeds along with chromatin condensation and remodeling while ensuring the fidelity of the replicated genome. Mapping replication initiation sites can provide clues for the coordination of DNA replication and transcription on a whole-genome scale. Here we discuss recent insights obtained from genome-scale analyses of replication initiation sites and transcription in mammalian cells and ask how transcription and chromatin modifications affect the frequency of replication initiation events. We also discuss DNA sequences, such as insulators and replicators, which modulate replication and transcription of target genes, and use genome-wide maps of replication initiation sites to evaluate possible commonalities between replicators and chromatin insulators. This article is part of a Special Issue entitled: Chromatin in time and space.
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27
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Sass S, Dietmann S, Burk UC, Brabletz S, Lutter D, Kowarsch A, Mayer KF, Brabletz T, Ruepp A, Theis FJ, Wang Y. MicroRNAs coordinately regulate protein complexes. BMC SYSTEMS BIOLOGY 2011; 5:136. [PMID: 21867514 PMCID: PMC3170341 DOI: 10.1186/1752-0509-5-136] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 08/25/2011] [Indexed: 02/06/2023]
Abstract
Background In animals, microRNAs (miRNAs) regulate the protein synthesis of their target messenger RNAs (mRNAs) by either translational repression or deadenylation. miRNAs are frequently found to be co-expressed in different tissues and cell types, while some form polycistronic clusters on genomes. Interactions between targets of co-expressed miRNAs (including miRNA clusters) have not yet been systematically investigated. Results Here we integrated information from predicted and experimentally verified miRNA targets to characterize protein complex networks regulated by human miRNAs. We found striking evidence that individual miRNAs or co-expressed miRNAs frequently target several components of protein complexes. We experimentally verified that the miR-141-200c cluster targets different components of the CtBP/ZEB complex, suggesting a potential orchestrated regulation in epithelial to mesenchymal transition. Conclusions Our findings indicate a coordinate posttranscriptional regulation of protein complexes by miRNAs. These provide a sound basis for designing experiments to study miRNA function at a systems level.
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Affiliation(s)
- Steffen Sass
- MIPS, Institute for Bioinformatics and System Biology, Helmholtz Center Munich, German Research Center for Environmental Health, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany
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Prevention of transcriptional silencing by a replicator-binding complex consisting of SWI/SNF, MeCP1, and hnRNP C1/C2. Mol Cell Biol 2011; 31:3472-84. [PMID: 21690294 DOI: 10.1128/mcb.05587-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcriptional silencing selectively impedes gene expression. Silencing is often accompanied by replication delay and can be prevented by replicator sequences. Here we report a replicator-binding protein complex involved in the prevention of transcriptional silencing. The protein complex interacts with an essential asymmetric region within the human β-globin Rep-P replicator and includes hnRNP C1/C2, SWI/SNF complex, and MeCP1, which are members of the locus control region (LCR)-associated remodeling complex (LARC). Interaction between LARC and Rep-P prevented transcriptional silencing and replication delay. Transgenes that did not contain the asymmetric LARC-binding region of Rep-P replicated late and exhibited stable silencing that could not be affected by a DNA methylation inhibitor. In contrast, transgenes that contain a mutation of the asymmetric region of Rep-P that could not bind LARC exhibited a silent state that could transiently be reactivated by DNA demethylation. The effect of DNA demethylation was transient, and prolonged exposure to a methylation inhibitor induced distinct, stable, methylation-independent silencing. These observations suggest that the interaction of LARC complex with replicators plays a role in preventing gene silencing and provides support for a novel, epigenetic mechanism of resistance to methylation inhibitors.
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29
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Lisse TS, Liu T, Irmler M, Beckers J, Chen H, Adams JS, Hewison M. Gene targeting by the vitamin D response element binding protein reveals a role for vitamin D in osteoblast mTOR signaling. FASEB J 2010; 25:937-47. [PMID: 21123297 DOI: 10.1096/fj.10-172577] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Transcriptional regulation by hormonal 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] involves occupancy of vitamin D response elements (VDREs) by the VDRE binding protein (VDRE-BP) or 1,25(OH)(2)D(3)-bound vitamin D receptor (VDR). This relationship is disrupted by elevated VDRE-BP, causing a form of hereditary vitamin D-resistant rickets (HVDRR). DNA array analysis showed that of 114 genes regulated by 1,25(OH)(2)D(3) in control cells, almost all (113) were rendered insensitive to the hormone in VDRE-BP-overexpressing HVDRR cells. Among these was the gene for DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling. Chromatin immunoprecipitation PCR using 1,25(OH)(2)D(3)-treated osteoblasts confirmed that VDR and VDRE-BP compete for binding to the DDIT4 gene promoter. Expression of DDIT4 mRNA in these cells was induced (1.6-6 fold) by 1,25(OH)(2)D(3) (10-100 nM), and Western blot and flow cytometry analysis showed that this response involved suppression of phosphorylated S6K1(T389) (a downstream target of mTOR) similar to rapamycin treatment. siRNA knockdown of DDIT4 completely abrogated antiproliferative responses to 1,25(OH)(2)D(3), whereas overexpression of VDRE-BP exerted a dominant-negative effect on transcription of 1,25(OH)(2)D(3)-target genes. DDIT4, an inhibitor of mTOR signaling, is a direct target for 1,25(OH)(2)D(3) and VDRE-BP, and functions to suppress cell proliferation in response to vitamin D.
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Affiliation(s)
- Thomas S Lisse
- Orthopaedic Hospital Research Center, University of California-Los Angeles, 615 Charles E. Young Dr., South Los Angeles, CA 90095, USA
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30
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Abstract
The hnRNPs (heterogeneous nuclear ribonucleoproteins) are RNA-binding proteins with important roles in multiple aspects of nucleic acid metabolism, including the packaging of nascent transcripts, alternative splicing and translational regulation. Although they share some general characteristics, they vary greatly in terms of their domain composition and functional properties. Although the traditional grouping of the hnRNPs as a collection of proteins provided a practical framework, which has guided much of the research on them, this approach is becoming increasingly incompatible with current knowledge about their structural and functional divergence. Hence, we review the current literature to examine hnRNP diversity, and discuss how this impacts upon approaches to the classification of RNA-binding proteins in general.
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Izquierdo JM. Heterogeneous ribonucleoprotein C displays a repressor activity mediated by T-cell intracellular antigen-1-related/like protein to modulate Fas exon 6 splicing through a mechanism involving Hu antigen R. Nucleic Acids Res 2010; 38:8001-14. [PMID: 20699271 PMCID: PMC3001070 DOI: 10.1093/nar/gkq698] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
T-cell intracellular antigen (TIA)-proteins are known regulators of alternative pre-mRNA splicing. In this study, pull-down experiments and mass spectrometry indicate that TIAR/TIAL1 and hnRNP C1/C2 are associated in HeLa nuclear extracts. Co-immunoprecipitation and GST-pull-down assays confirmed this interaction. Interestingly, binding requires the glutamine-rich (Q-rich) C-terminal domain of TIAR and the leucine-rich plus acidic residues-rich C-terminal domains of hnRNP C1/C2. This interaction also occurs in an RNA-dependent manner. Recombinant GFP-TIAR and RFP-hnRNP C1 proteins display partial nuclear co-localization when overexpressed in HeLa cells, and this requires the Q-rich domain of TIAR. hnRNP C1 overexpression in the presence of rate-limiting amounts of TIAR in HeLa and HEK293 cells affects alternative splicing of Fas and FGFR2 minigenes, promoting Fas exon 6 and FGFR2 exon K-SAM skipping, respectively. The repressor activity of hnRNP C1 on Fas exon 6 splicing is mediated by Hu antigen R (HuR). Experiments involving tethering approaches showed that the repressor capacity of hnRNP C1 is associated with an exonic splicing silencer in Fas exon 6. This effect was reversed by splice-site strengthening and is linked to its basic leucine zipper-like motif. These results suggest that hnRNP C1/C2 acts as a bridge between HuR and TIAR to modulate alternative Fas splicing.
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Affiliation(s)
- José M Izquierdo
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, C/Nicolás Cabrera 1, Lab-107, Cantoblanco, 28049 Madrid, Spain.
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Sankaran VG, Xu J, Orkin SH. Advances in the understanding of haemoglobin switching. Br J Haematol 2010; 149:181-94. [PMID: 20201948 DOI: 10.1111/j.1365-2141.2010.08105.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The study of haemoglobin switching has represented a focus in haematology due in large part to the clinical relevance of the fetal to adult haemoglobin switch for developing targeted approaches to ameliorate the severity of the beta-haemoglobinopathies. Additionally, the process by which this switch occurs represents an important paradigm for developmental gene regulation. In this review, we provide an overview of both the embryonic primitive to definitive switch in haemoglobin expression, as well as the fetal to adult switch that is unique to humans and old world monkeys. We discuss the nature of these switches and models of their regulation. The factors that have been suggested to regulate this process are then discussed. With the increased understanding and discovery of molecular regulators of haemoglobin switching, such as BCL11A, new avenues of research may lead ultimately to novel therapeutic, mechanism-based approaches to fetal haemoglobin reactivation in patients.
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Affiliation(s)
- Vijay G Sankaran
- Division of Hematology/Oncology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
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Minard ME, Jain AK, Barton MC. Analysis of epigenetic alterations to chromatin during development. Genesis 2009; 47:559-72. [PMID: 19603511 DOI: 10.1002/dvg.20534] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Each cell within a multicellular organism has distinguishable characteristics established by its unique patterns of gene expression. This individual identity is determined by the expression of genes in a time and place-dependent manner, and it is becoming increasingly clear that chromatin plays a fundamental role in the control of gene transcription in multicellular organisms. Therefore, understanding the regulation of chromatin and how the distinct identity of a cell is passed to daughter cells during development is paramount. Techniques with which to study chromatin have advanced rapidly over the past decade. Development of high throughput techniques and their proper applications has provided us essential tools to understand the regulation of epigenetic phenomena and its effect on gene expression. Understanding the changes that occur in chromatin during the course of development will not only contribute to our knowledge of normal gene expression, but will also add to our knowledge of how gene expression goes awry during disease. This review opens with an introduction to some of the key premises of epigenetic regulation of gene expression. A discussion of experimental techniques with which one can study epigenetic alterations to chromatin during development follows, emphasizing recent breakthroughs in this area. We then present examples of epigenetic mechanisms exploited in the control of developmental cell fate and regulation of tissue-specific gene expression. Finally, we discuss some of the frontiers and challenges in this area of research.
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Affiliation(s)
- Meghan E Minard
- Department of Biochemistry and Molecular Biology, Center for Cancer Epigenetics, University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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Ross J, Bottardi S, Bourgoin V, Wollenschlaeger A, Drobetsky E, Trudel M, Milot E. Differential requirement of a distal regulatory region for pre-initiation complex formation at globin gene promoters. Nucleic Acids Res 2009; 37:5295-308. [PMID: 19567738 PMCID: PMC2760785 DOI: 10.1093/nar/gkp545] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Although distal regulatory regions are frequent throughout the genome, the molecular mechanisms by which they act in a promoter-specific manner remain to be elucidated. The human β-globin locus constitutes an extremely well-established multigenic model to investigate this issue. In erythroid cells, the β-globin locus control region (LCR) exerts distal regulatory function by influencing local chromatin organization and inducing high-level expression of individual β-like globin genes. Moreover, in transgenic mice expressing the entire human β-globin locus, deletion of LCR-hypersensitive site 2 (HS2) can alter β-like globin gene expression. Here, we show that abnormal expression of human β-like globin genes in the absence of HS2 is associated with decreased efficacy of pre-initiation complex formation at the human ɛ- and γ-promoters, but not at the β-promoter. This promoter-specific phenomenon is associated with reduced long-range interactions between the HS2-deleted LCR and human γ-promoters. We also find that HS2 is dispensable for high-level human β-gene transcription, whereas deletion of this hypersensitive site can alter locus chromatin organization; therefore the functions exerted by HS2 in transcriptional enhancement and locus chromatin organization are distinct. Overall, our data delineate one mechanism whereby a distal regulatory region provides promoter-specific transcriptional enhancement.
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Affiliation(s)
- Julie Ross
- Faculty of Medicine, University of Montreal, Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
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35
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Towards a genome-wide reconstruction of cis-regulatory networks in the human genome. Semin Cell Dev Biol 2009; 20:842-8. [PMID: 19560550 DOI: 10.1016/j.semcdb.2009.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 06/12/2009] [Indexed: 11/21/2022]
Abstract
The vast amount of recent progress made on the sequence of the human genome has allowed an unprecedented examination of cis-regulatory networks. These networks consist of functional elements such as promoters, enhancers, silencers, and insulators, and their coordinated activity is responsible for regulation of gene expression. Recent studies surveyed the entire genome, identifying novel elements and evaluating functional differences in respect to development. These investigations present the first steps towards a global regulatory map for expression in the human genome.
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36
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BRG1 requirement for long-range interaction of a locus control region with a downstream promoter. Proc Natl Acad Sci U S A 2009; 106:2259-64. [PMID: 19171905 DOI: 10.1073/pnas.0806420106] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dynamic packaging of DNA into chromatin is a fundamental step in the control of diverse nuclear processes. Whereas certain transcription factors and chromosomal components promote the formation of higher-order chromatin loops, the co-regulator machinery mediating loop assembly and disassembly is unknown. Using mice bearing a hypomorphic allele of the BRG1 chromatin remodeler, we demonstrate that the Brg1 mutation abrogated a cell type-specific loop between the beta-globin locus control region and the downstream beta major promoter, despite trans-acting factor occupancy at both sites. By contrast, distinct loops were insensitive to the Brg1 mutation. Molecular analysis with a conditional allele of GATA-1, a key regulator of hematopoiesis, in a novel cell-based system provided additional evidence that BRG1 functions early in chromatin domain activation to mediate looping. Although the paradigm in which chromatin remodelers induce nucleosome structural transitions is well established, our results demonstrating an essential role of BRG1 in the genesis of specific chromatin loops expands the repertoire of their functions.
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González-Lamothe R, Boyle P, Dulude A, Roy V, Lezin-Doumbou C, Kaur GS, Bouarab K, Després C, Brisson N. The transcriptional activator Pti4 is required for the recruitment of a repressosome nucleated by repressor SEBF at the potato PR-10a gene. THE PLANT CELL 2008; 20:3136-47. [PMID: 19028963 PMCID: PMC2613659 DOI: 10.1105/tpc.108.061721] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 10/22/2008] [Accepted: 11/03/2008] [Indexed: 05/22/2023]
Abstract
Transcriptional reprogramming is critical for plant disease resistance responses. In potato (Solanum tuberosum), the marker gene PATHOGENESIS-RELATED-10a (PR-10a) is transcriptionally activated by pathogens, wounding, or elicitor treatment. Activation of PR-10a requires the recruitment of the activator Why1 to its promoter. In addition, PR-10a is negatively regulated by the repressor SEBF (for Silencer Element Binding Factor). Here, we show through a yeast two-hybrid screen that SEBF interacts with Pti4, which has been shown to be a transcriptional activator. SEBF recruits Pti4 via its consensus sequence-type RNA binding domain, while Pti4 is recruited to SEBF by means of its ethylene-response factor domain. In vivo plant transcription assays confirmed that SEBF interacts with Pti4 to form a repressosome, showing that Pti4 can also play a role in transcriptional repression. Chromatin immunoprecipitation revealed that both SEBF and Pti4 are recruited to the PR-10a promoter in uninduced conditions only and that the recruitment of Pti4 is dependent on the presence of SEBF, consistent with the fact that there is no Pti4 consensus binding site in PR-10a. Unexpectedly, we also demonstrated that recruitment of SEBF was dependent on the presence of Pti4, thereby explaining why SEBF, itself a repressor, requires Pti4 for its repressing function.
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38
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Venables JP, Koh CS, Froehlich U, Lapointe E, Couture S, Inkel L, Bramard A, Paquet ER, Watier V, Durand M, Lucier JF, Gervais-Bird J, Tremblay K, Prinos P, Klinck R, Elela SA, Chabot B. Multiple and specific mRNA processing targets for the major human hnRNP proteins. Mol Cell Biol 2008; 28:6033-43. [PMID: 18644864 PMCID: PMC2547008 DOI: 10.1128/mcb.00726-08] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 05/30/2008] [Accepted: 07/11/2008] [Indexed: 12/22/2022] Open
Abstract
Alternative splicing is a key mechanism regulating gene expression, and it is often used to produce antagonistic activities particularly in apoptotic genes. Heterogeneous nuclear ribonucleoparticle (hnRNP) proteins form a family of RNA-binding proteins that coat nascent pre-mRNAs. Many but not all major hnRNP proteins have been shown to participate in splicing control. The range and specificity of hnRNP protein action remain poorly documented, even for those affecting splice site selection. We used RNA interference and a reverse transcription-PCR screening platform to examine the implications of 14 of the major hnRNP proteins in the splicing of 56 alternative splicing events in apoptotic genes. Out of this total of 784 alternative splicing reactions tested in three human cell lines, 31 responded similarly to a knockdown in at least two different cell lines. On the other hand, the impact of other hnRNP knockdowns was cell line specific. The broadest effects were obtained with hnRNP K and C, two proteins whose role in alternative splicing had not previously been firmly established. Different hnRNP proteins affected distinct sets of targets with little overlap even between closely related hnRNP proteins. Overall, our study highlights the potential contribution of all of these major hnRNP proteins in alternative splicing control and shows that the targets for individual hnRNP proteins can vary in different cellular contexts.
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Affiliation(s)
- Julian P Venables
- Département de Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, 3001, 12th Avenue Nord, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
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Cazanove O, Batut J, Scarlett G, Mumford K, Elgar S, Thresh S, Neant I, Moreau M, Guille M. Methylation of Xilf3 by Xprmt1b Alters Its DNA, but Not RNA, Binding Activity. Biochemistry 2008; 47:8350-7. [DOI: 10.1021/bi7008486] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ophelie Cazanove
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Julie Batut
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Garry Scarlett
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Katherine Mumford
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Stuart Elgar
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Sarah Thresh
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Isabelle Neant
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Marc Moreau
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
| | - Matthew Guille
- Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, U.K., and Centre de Biologie du Développement, UMR 5547 CNRS/UPS, 118 Route de, Narbonne, 31062 Toulouse Cedex 04, France
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40
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Clouaire T, Stancheva I. Methyl-CpG binding proteins: specialized transcriptional repressors or structural components of chromatin? Cell Mol Life Sci 2008; 65:1509-22. [PMID: 18322651 PMCID: PMC2873564 DOI: 10.1007/s00018-008-7324-y] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
DNA methylation is an epigenetic modification that is implicated in transcriptional silencing. It is becoming increasingly clear that both correct levels and proper interpretation of DNA methylation are important for normal development and function of many organisms, including humans. In this review we focus on recent advances in understanding how proteins that bind to methylated DNA recognize their binding sites and translate the DNA methylation signal into functional states of chromatin. Although the function of methyl-CpG binding proteins in transcriptional repression has been attributed to their cooperation with co-repressor complexes, additional roles for these proteins in chromatin compaction and spatial organization of nuclear domains have also been proposed. Finally, we provide a brief overview of how methyl-CpG proteins contribute to human disease processes such as Rett syndrome and cancer.
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Affiliation(s)
- T. Clouaire
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Mayfield Road, Edinburgh, EH9 3JR United Kingdom
| | - I. Stancheva
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Mayfield Road, Edinburgh, EH9 3JR United Kingdom
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41
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Abstract
The developmental changes in expression of the beta like genes from embryonic to adult stages of human life are controlled at least partially at the level of the promoter sequences of these genes and their binding factors, and competition for promoter specific interactions with the locus control region (LCR). In recent years, the control of beta globin genes has also been investigated at the level of chromatin structure involving the chemical modification of histones and their remodelling by DNA dependent ATPases (SMARCA) containing protein complexes. The role of intergenic RNA is also being investigated with renewed interest. Although a wealth of information on the structure/function relationship of the LCR and globin promoters has been gathered over more than two decades, the fundamental nature of the control of these genes at the molecular level is still not completely understood. In the following pages, we intend to briefly describe the progress made in the field and discuss future directions.
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Affiliation(s)
- Milind C Mahajan
- Department of Human Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
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42
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Abstract
Transcriptional networks orchestrate fundamental biological processes, including hematopoiesis, in which hematopoietic stem cells progressively differentiate into specific progenitors cells, which in turn give rise to the diverse blood cell types. Whereas transcription factors recruit coregulators to chromatin, leading to targeted chromatin modification and recruitment of the transcriptional machinery, many questions remain unanswered regarding the underlying molecular mechanisms. Furthermore, how diverse cell type-specific transcription factors function cooperatively or antagonistically in distinct cellular contexts is poorly understood, especially since genes in higher eukaryotes commonly encompass broad chromosomal regions (100 kb and more) and are littered with dispersed regulatory sequences. In this article, we describe an important set of transcription factors and coregulators that control erythropoiesis and highlight emerging transcriptional mechanisms and principles. It is not our intent to comprehensively survey all factors implicated in the transcriptional control of erythropoiesis, but rather to underscore specific mechanisms, which have potential to be broadly relevant to transcriptional control in diverse systems.
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Sumoylation of EKLF promotes transcriptional repression and is involved in inhibition of megakaryopoiesis. Mol Cell Biol 2007; 27:8547-60. [PMID: 17938210 DOI: 10.1128/mcb.00589-07] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Erythroid Krüppel-like factor (EKLF [KLF1]) is a transcriptional regulator that plays a critical role within a specific subset of hematopoietic cells, particularly in the erythroid lineage and its immediate precursor, the megakaryocyte-erythroid progenitor (MEP). We find that EKLF is posttranslationally modified by sumoylation at a single site near its amino terminus and that PIAS1 plays a critical role in this process. Mutation of this site has little effect on EKLF's ability to function as a transcriptional activator; however, it has a dramatic effect on its repressive abilities. The mechanism of repression likely involves a novel small ubiquitin-related modifier (SUMO)-dependent EKLF interaction with the Mi-2beta component of the NuRD repression complex. Mutated EKLF is attenuated in its ability to repress megakaryocyte differentiation, implicating EKLF sumoylation status in differentiative decisions emanating from the MEP. These studies demonstrate a novel mechanism by which transcription factor sumoylation can alter protein-protein interactions and bipotential lineage decisions.
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Martinez-Contreras R, Cloutier P, Shkreta L, Fisette JF, Revil T, Chabot B. hnRNP proteins and splicing control. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 623:123-47. [PMID: 18380344 DOI: 10.1007/978-0-387-77374-2_8] [Citation(s) in RCA: 273] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Proteins of the heterogeneous nuclear ribonucleoparticles (hnRNP) family form a structurally diverse group of RNA binding proteins implicated in various functions in metazoans. Here we discuss recent advances supporting a role for these proteins in precursor-messenger RNA (pre-mRNA) splicing. Heterogeneous nuclear RNP proteins can repress splicing by directly antagonizing the recognition of splice sites, or can interfere with the binding of proteins bound to enhancers. Recently, hnRNP proteins have been shown to hinder communication between factors bound to different splice sites. Conversely, several reports have described a positive role for some hnRNP proteins in pre-mRNA splicing. Moreover, cooperative interactions between bound hnRNP proteins may encourage splicing between specific pairs of splice sites while simultaneously hampering other combinations. Thus, hnRNP proteins utilize a variety of strategies to control splice site selection in a manner that is important for both alternative and constitutive pre-mRNA splicing.
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45
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Winteringham LN, Endersby R, Kobelke S, McCulloch RK, Williams JH, Stillitano J, Cornwall SM, Ingley E, Klinken SP. Myeloid Leukemia Factor 1 Associates with a Novel Heterogeneous Nuclear Ribonucleoprotein U-like Molecule. J Biol Chem 2006; 281:38791-800. [PMID: 17008314 DOI: 10.1074/jbc.m605401200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myeloid leukemia factor 1 (MLF1) is an oncoprotein associated with hemopoietic lineage commitment and acute myeloid leukemia. Here we show that Mlf1 associated with a novel binding partner, Mlf1-associated nuclear protein (Manp), a new heterogeneous nuclear ribonucleoprotein (hnRNP) family member, related to hnRNP-U. Manp localized exclusively in the nucleus and could redirect Mlf1 from the cytoplasm into the nucleus. The nuclear content of Mlf1 was also regulated by 14-3-3 binding to a canonical 14-3-3 binding motif within the N terminus of Mlf1. Significantly Mlf1 contains a functional nuclear export signal and localized primarily to the nuclei of hemopoietic cells. Mlf1 was capable of binding DNA, and microarray analysis revealed that it affected the expression of several genes, including transcription factors. In summary, this study reveals that Mlf1 translocates between nucleus and cytoplasm, associates with a novel hnRNP, and influences gene expression.
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Affiliation(s)
- Louise N Winteringham
- Laboratory for Cancer Medicine, Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Perth, Western Australia 6000, Australia
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46
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Chen H, Hewison M, Adams JS. Functional Characterization of Heterogeneous Nuclear Ribonuclear Protein C1/C2 in Vitamin D Resistance. J Biol Chem 2006; 281:39114-20. [PMID: 17071612 DOI: 10.1074/jbc.m608006200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Clinically apparent hereditary vitamin D-resistant rickets (HVDRR) usually results from a loss of function mutation in the vitamin D receptor (VDR). We recently described a human with the classical HVDRR phenotype but normal VDR function. Hormone resistance resulted from constitutive overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) that competed with a normally functioning VDR-retinoid X receptor (RXR) dimer for binding to the vitamin D response element (VDRE). Here we describe the purification, molecular cloning, and expression of this vitamin D resistance-causing, competitive response element-binding protein (REBiP) hnRNP C1/C2. When overexpressed in vitamin D-responsive cells, cDNAs for both hnRNPC1 and hnRNPC2 inhibited VDR-VDRE-directed transactivation (28 and 43%, respectively; both p < 0.005). By contrast, transient expression of an hnRNP C1/C2 small interfering RNA increased VDR transactivation by 39% (p < 0.005). Chromatin immunoprecipitation of nucleoproteins bound to the transcriptionally active 1,25-dihydroxy vitamin D-driven CYP24 promoter revealed the presence of REBiP in vitamin D-responsive human cells and indicated that the normal pattern of 1,25-dihydroxy vitamin D-initiated cyclical movement of the VDR on and off the VDRE is legislated by competitive, reciprocal occupancy of the VDRE by hnRNP C1/C2. The temporal and reciprocal pattern of VDR and hnRNPC1/C2 interaction with the VDRE was lost in HVDRR cells overexpressing the hnRNP C1/C2 REBiP. These observations provide further evidence for the functional importance of REBiP as a component of the multiprotein complex involved in the regulation of vitamin D-mediated transcription. In particular, chromatin immunoprecipitation data suggest that, in addition to its RNA-processing functions, hnRNP C1/C2 may be a key determinant of the temporal patterns of VDRE occupancy.
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Affiliation(s)
- Hong Chen
- Division of Endocrinology, Diabetes and Metabolism, Burns and Allen Research Institute, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, California 90048, USA
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47
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Reply to “Testing for association between MeCP2 and the brahma-associated SWI/SNF chromatin-remodeling complex”. Nat Genet 2006. [DOI: 10.1038/ng0906-964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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48
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Bresnick EH, Johnson KD, Kim SI, Im H. Establishment and regulation of chromatin domains: mechanistic insights from studies of hemoglobin synthesis. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2006; 81:435-71. [PMID: 16891178 DOI: 10.1016/s0079-6603(06)81011-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Emery H Bresnick
- Department of Pharmacology, University of Wisconsin Medical School, 383 Medical Sciences Center, Madison, Wisconsin 53706, USA
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