1
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EKLF/Klf1 regulates erythroid transcription by its pioneering activity and selective control of RNA Pol II pause-release. Cell Rep 2022; 41:111830. [PMID: 36543143 PMCID: PMC9879271 DOI: 10.1016/j.celrep.2022.111830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/06/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022] Open
Abstract
EKLF/Klf1 is a zinc-finger transcription activator essential for erythroid lineage commitment and terminal differentiation. Using ChIP-seq, we investigate EKLF DNA binding and transcription activation mechanisms during mouse embryonic erythropoiesis. We utilize the Nan/+ mouse that expresses the EKLF-E339D (Nan) variant mutated in its conserved zinc-finger region and address the mechanism of hypomorphic and neomorphic changes in downstream gene expression. First, we show that Nan-EKLF limits normal EKLF binding to a subset of its sites. Second, we find that ectopic binding of Nan-EKLF occurs largely at enhancers and activates transcription through pioneering activity. Third, we find that for a subset of ectopic targets, gene activation is achieved in Nan/+ only by Nan-EKLF binding to distal enhancers, leading to RNA polymerase II pause-release. These results have general applicability to understanding how a DNA binding variant factor confers dominant disruptive effects on downstream gene expression even in the presence of its normal counterpart.
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2
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Krüppel-Like Factor 1: A Pivotal Gene Regulator in Erythropoiesis. Cells 2022; 11:cells11193069. [PMID: 36231031 PMCID: PMC9561966 DOI: 10.3390/cells11193069] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/21/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022] Open
Abstract
Krüppel-like factor 1 (KLF1) plays a crucial role in erythropoiesis. In-depth studies conducted on mice and humans have highlighted its importance in erythroid lineage commitment, terminal erythropoiesis progression and the switching of globin genes from γ to β. The role of KLF1 in haemoglobin switching is exerted by the direct activation of β-globin gene and by the silencing of γ-globin through activation of BCL11A, an important γ-globin gene repressor. The link between KLF1 and γ-globin silencing identifies this transcription factor as a possible therapeutic target for β-hemoglobinopathies. Moreover, several mutations have been identified in the human genes that are responsible for various benign phenotypes and erythroid disorders. The study of the phenotype associated with each mutation has greatly contributed to the current understanding of the complex role of KLF1 in erythropoiesis. This review will focus on some of the principal functions of KLF1 on erythroid cell commitment and differentiation, spanning from primitive to definitive erythropoiesis. The fundamental role of KLF1 in haemoglobin switching will be also highlighted. Finally, an overview of the principal human mutations and relative phenotypes and disorders will be described.
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3
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King R, Gallagher PJ, Khoriaty R. The congenital dyserythropoieitic anemias: genetics and pathophysiology. Curr Opin Hematol 2022; 29:126-136. [PMID: 35441598 PMCID: PMC9021540 DOI: 10.1097/moh.0000000000000697] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW The congenital dyserythropoietic anemias (CDA) are hereditary disorders characterized by ineffective erythropoiesis. This review evaluates newly developed CDA disease models, the latest advances in understanding the pathogenesis of the CDAs, and recently identified CDA genes. RECENT FINDINGS Mice exhibiting features of CDAI were recently generated, demonstrating that Codanin-1 (encoded by Cdan1) is essential for primitive erythropoiesis. Additionally, Codanin-1 was found to physically interact with CDIN1, suggesting that mutations in CDAN1 and CDIN1 result in CDAI via a common mechanism. Recent advances in CDAII (which results from SEC23B mutations) have also been made. SEC23B was found to functionally overlap with its paralogous protein, SEC23A, likely explaining the absence of CDAII in SEC23B-deficient mice. In contrast, mice with erythroid-specific deletion of 3 or 4 of the Sec23 alleles exhibited features of CDAII. Increased SEC23A expression rescued the CDAII erythroid defect, suggesting a novel therapeutic strategy for the disease. Additional recent advances included the identification of new CDA genes, RACGAP1 and VPS4A, in CDAIII and a syndromic CDA type, respectively. SUMMARY Establishing cellular and animal models of CDA is expected to result in improved understanding of the pathogenesis of these disorders, which may ultimately lead to the development of new therapies.
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Affiliation(s)
- Richard King
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- University of Michigan Rogel Cancer Center, Ann Arbor, Michigan, USA
| | - Patrick J. Gallagher
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Rami Khoriaty
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- University of Michigan Rogel Cancer Center, Ann Arbor, Michigan, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
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4
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Kulczynska-Figurny K, Bieker JJ, Siatecka M. Severe anemia caused by dominant mutations in Krüppel-like factor 1 (KLF1). MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 786:108336. [PMID: 33339573 DOI: 10.1016/j.mrrev.2020.108336] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/23/2020] [Accepted: 09/29/2020] [Indexed: 10/23/2022]
Abstract
The etiology and severity of anemia, a common blood disorder, are diverse. Dominant mutations in Krüppel-like factor 1 (KLF1/EKLF) underlie the molecular basis for some of them. KLF1 is a zinc finger transcription factor that plays an essential role in red blood cell proliferation and differentiation. Mutations have been identified in the KLF1 gene that cause hematologic diseases. Two of these alter one allele but generate an extreme phenotype: the mouse Nan mutation (E339D) leads to hemolytic neonatal anemia with hereditary spherocytosis, and the human CDA mutation (E325K) causes congenital dyserythropoietic anemia (CDA) type IV. These modify functionally important amino acids in the zinc finger DNA-binding domain at positions involved in direct interactions with regulatory elements of KLF1's target genes. Although the two dominant mutations alter the same evolutionarily conserved glutamic acid residue, the substitutions are not equivalent and lead to divergent consequences for the molecular mechanisms underlying activity of these mutants, particularly in recognition and interaction with their unique binding sites. Consequently, the properties of the protein are transformed such that it acquires novel dominant characteristics whose effects may not be limited to the erythroid compartment. KLF1 mutants cause loss-of-function/haploinsufficiency effects on some KLF1 wild-type target genes, while at the same time gain-of-function effects activate ectopic sites and neomorphic gene expression. Such anomalies not only lead to intrinsic red cell problems, but also to expression of non-erythroid genes that systemically disturb organ development. This review highlights recent molecular, biochemical, and genetic studies of KLF1 mutants, particularly the dramatic consequences that come from just a single amino acid change. The study of these variants provides an important contribution to the overall understanding of the DNA-protein interface of the zinc finger subtype of transcription factors, and the potential clinical consequences of what might appear to be a minor change in sequence.
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Affiliation(s)
| | - James J Bieker
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Miroslawa Siatecka
- Department of Genetics, Faculty of Biology, University of Adam Mickiewicz, Poznan, 61-614, Poland.
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5
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A Krüppel-like factor 1 ( KLF1) Mutation Associated with Severe Congenital Dyserythropoietic Anemia Alters Its DNA-Binding Specificity. Mol Cell Biol 2020; 40:MCB.00444-19. [PMID: 31818881 DOI: 10.1128/mcb.00444-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 12/04/2019] [Indexed: 11/20/2022] Open
Abstract
Krüppel-like factor 1 (KLF1/EKLF) is a transcription factor that globally activates genes involved in erythroid cell development. Various mutations are identified in the human KLF1 gene. The E325K mutation causes congenital dyserythropoietic anemia (CDA) type IV, characterized by severe anemia and non-erythroid-cell-related symptoms. The CDA mutation is in the second zinc finger of KLF1 at a position functionally involved in its interactions with DNA. The molecular parameters of how CDA-KLF1 exerts its biological effects have not been addressed. Here, using an in vitro selection strategy, we determined the preferred DNA-binding site for CDA-KLF1. Binding to the deduced consensus sequence is supported by in vitro gel shifts and by in vivo functional reporter gene studies. Two significant changes compared to wild-type (WT) binding are observed: G is selected as the middle nucleotide, and the 3' portion of the consensus sequence is more degenerate. As a consequence, CDA-KLF1 did not bind the WT consensus sequence. However, activation of ectopic sites is promoted. Continuous activation of WT target genes occurs if they fortuitously contain the novel CDA site nearby. Our findings provide a molecular understanding of how a single mutation in the KLF1 zinc finger exerts effects on erythroid physiology in CDA type IV.
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6
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Syndromic immune disorder caused by a viable hypomorphic allele of spliceosome component Snrnp40. Nat Immunol 2019; 20:1322-1334. [PMID: 31427773 DOI: 10.1038/s41590-019-0464-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 07/08/2019] [Indexed: 02/06/2023]
Abstract
We report a new immunodeficiency disorder in mice caused by a viable hypomorphic mutation of Snrnp40, an essential gene encoding a subunit of the U5 small nuclear ribonucleoprotein (snRNP) complex of the spliceosome. Snrnp40 is ubiquitous but strongly expressed in lymphoid tissue. Homozygous mutant mice showed hypersusceptibility to infection by murine cytomegalovirus and multiple defects of lymphoid development, stability and function. Cell-intrinsic defects of hematopoietic stem cell differentiation also affected homozygous mutants. SNRNP40 deficiency in primary hematopoietic stem cells or T cells or the EL4 cell line increased the frequency of splicing errors, mostly intron retention, in several hundred messenger RNAs. Altered expression of proteins associated with immune cell function was also observed in Snrnp40-mutant cells. The immunological consequences of SNRNP40 deficiency presumably result from cumulative, moderate effects on processing of many different mRNA molecules and secondary reductions in the expression of critical immune proteins, yielding a syndromic immune disorder.
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7
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Ilsley MD, Huang S, Magor GW, Landsberg MJ, Gillinder KR, Perkins AC. Corrupted DNA-binding specificity and ectopic transcription underpin dominant neomorphic mutations in KLF/SP transcription factors. BMC Genomics 2019; 20:417. [PMID: 31126231 PMCID: PMC6534859 DOI: 10.1186/s12864-019-5805-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 05/17/2019] [Indexed: 02/07/2023] Open
Abstract
Background Mutations in the transcription factor, KLF1, are common within certain populations of the world. Heterozygous missense mutations in KLF1 mostly lead to benign phenotypes, but a heterozygous mutation in a DNA-binding residue (E325K in human) results in severe Congenital Dyserythropoietic Anemia type IV (CDA IV); i.e. an autosomal-dominant disorder characterized by neonatal hemolysis. Results To investigate the biochemical and genetic mechanism of CDA IV, we generated murine erythroid cell lines that harbor tamoxifen-inducible (ER™) versions of wild type and mutant KLF1 on a Klf1−/− genetic background. Nuclear translocation of wild type KLF1 results in terminal erythroid differentiation, whereas mutant KLF1 results in hemolysis without differentiation. The E to K variant binds poorly to the canonical 9 bp recognition motif (NGG-GYG-KGG) genome-wide but binds at high affinity to a corrupted motif (NGG-GRG-KGG). We confirmed altered DNA-binding specificity by quantitative in vitro binding assays of recombinant zinc-finger domains. Our results are consistent with previously reported structural data of KLF-DNA interactions. We employed 4sU-RNA-seq to show that a corrupted transcriptome is a direct consequence of aberrant DNA binding. Conclusions Since all KLF/SP family proteins bind DNA in an identical fashion, these results are likely to be generally applicable to mutations in all family members. Importantly, they explain how certain mutations in the DNA-binding domain of transcription factors can generate neomorphic functions that result in autosomal dominant disease. Electronic supplementary material The online version of this article (10.1186/s12864-019-5805-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Melissa D Ilsley
- Mater Research, Translational Research Institute, University of Queensland, Brisbane, QLD, Australia.,School of Biomedical Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Stephen Huang
- Mater Research, Translational Research Institute, University of Queensland, Brisbane, QLD, Australia.,School of Biomedical Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Graham W Magor
- Mater Research, Translational Research Institute, University of Queensland, Brisbane, QLD, Australia.,Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, Australia
| | - Michael J Landsberg
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Kevin R Gillinder
- Mater Research, Translational Research Institute, University of Queensland, Brisbane, QLD, Australia. .,Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, Australia.
| | - Andrew C Perkins
- Mater Research, Translational Research Institute, University of Queensland, Brisbane, QLD, Australia.,Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, Australia
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8
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Cantú I, van de Werken HJG, Gillemans N, Stadhouders R, Heshusius S, Maas A, Esteghamat F, Ozgur Z, van IJcken WFJ, Grosveld F, von Lindern M, Philipsen S, van Dijk TB. The mouse KLF1 Nan variant impairs nuclear condensation and erythroid maturation. PLoS One 2019; 14:e0208659. [PMID: 30921348 PMCID: PMC6438607 DOI: 10.1371/journal.pone.0208659] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 03/11/2019] [Indexed: 12/13/2022] Open
Abstract
Krüppel-like factor 1 (KLF1) is an essential transcription factor for erythroid development, as demonstrated by Klf1 knockout mice which die around E14 due to severe anemia. In humans, >140 KLF1 variants, causing different erythroid phenotypes, have been described. The KLF1 Nan variant, a single amino acid substitution (p.E339D) in the DNA binding domain, causes hemolytic anemia and is dominant over wildtype KLF1. Here we describe the effects of the KLF1 Nan variant during fetal development. We show that Nan embryos have defects in erythroid maturation. RNA-sequencing of the KLF1 Nan fetal liver cells revealed that Exportin 7 (Xpo7) was among the 782 deregulated genes. This nuclear exportin is implicated in terminal erythroid differentiation; in particular it is involved in nuclear condensation. Indeed, KLF1 Nan fetal liver cells had larger nuclei and reduced chromatin condensation. Knockdown of XPO7 in wildtype erythroid cells caused a similar phenotype. We propose that reduced expression of XPO7 is partially responsible for the erythroid defects observed in KLF1 Nan erythroid cells.
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Affiliation(s)
- Ileana Cantú
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Nynke Gillemans
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Steven Heshusius
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
- Department of Hematopoiesis, Sanquin Research, Amsterdam, The Netherlands
| | - Alex Maas
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Zeliha Ozgur
- Center for Biomics, Erasmus MC, Rotterdam, The Netherlands
| | | | - Frank Grosveld
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Sjaak Philipsen
- Department of Cell Biology, Erasmus MC, Rotterdam, The Netherlands
- * E-mail:
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9
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Gnanapragasam MN, Crispino JD, Ali AM, Weinberg R, Hoffman R, Raza A, Bieker JJ. Survey and evaluation of mutations in the human KLF1 transcription unit. Sci Rep 2018; 8:6587. [PMID: 29700354 PMCID: PMC5920080 DOI: 10.1038/s41598-018-24962-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/12/2018] [Indexed: 01/03/2023] Open
Abstract
Erythroid Krüppel-like Factor (EKLF/KLF1) is an erythroid-enriched transcription factor that plays a global role in all aspects of erythropoiesis, including cell cycle control and differentiation. We queried whether its mutation might play a role in red cell malignancies by genomic sequencing of the KLF1 transcription unit in cell lines, erythroid neoplasms, dysplastic disorders, and leukemia. In addition, we queried published databases from a number of varied sources. In all cases we only found changes in commonly notated SNPs. Our results suggest that if there are mutations in KLF1 associated with erythroid malignancies, they are exceedingly rare.
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Affiliation(s)
- Merlin Nithya Gnanapragasam
- Department of Cell, Developmental, and Regenerative Biology, Mount Sinai School of Medicine, New York, NY, 10029, USA
| | - John D Crispino
- Department of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Abdullah M Ali
- Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA
| | - Rona Weinberg
- Cellular Therapy Laboratory, New York Blood Center, New York, NY, 10065, USA
| | - Ronald Hoffman
- Department of Medicine, Mount Sinai School of Medicine, New York, NY, 10029, USA
| | - Azra Raza
- Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA
| | - James J Bieker
- Department of Cell, Developmental, and Regenerative Biology, Mount Sinai School of Medicine, New York, NY, 10029, USA.
- Tisch Cancer Institute, Mount Sinai School of Medicine, New York, NY, 10029, USA.
- Black Familly Stem Cell Institute, Mount Sinai School of Medicine, New York, NY, 10029, USA.
- Mindich Child Health and Development Institute, Mount Sinai School of Medicine, New York, NY, 10029, USA.
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10
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Gillinder KR, Ilsley MD, Nébor D, Sachidanandam R, Lajoie M, Magor GW, Tallack MR, Bailey T, Landsberg MJ, Mackay JP, Parker MW, Miles LA, Graber JH, Peters LL, Bieker JJ, Perkins AC. Promiscuous DNA-binding of a mutant zinc finger protein corrupts the transcriptome and diminishes cell viability. Nucleic Acids Res 2017; 45:1130-1143. [PMID: 28180284 PMCID: PMC5388391 DOI: 10.1093/nar/gkw1014] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/13/2016] [Accepted: 11/02/2016] [Indexed: 12/27/2022] Open
Abstract
The rules of engagement between zinc finger transcription factors and DNA have been partly defined by in vitro DNA-binding and structural studies, but less is known about how these rules apply in vivo. Here, we demonstrate how a missense mutation in the second zinc finger of Krüppel-like factor-1 (KLF1) leads to degenerate DNA-binding specificity in vivo, resulting in ectopic transcription and anemia in the Nan mouse model. We employed ChIP-seq and 4sU-RNA-seq to identify aberrant DNA-binding events genome wide and ectopic transcriptional consequences of this binding. We confirmed novel sequence specificity of the mutant recombinant zinc finger domain by performing biophysical measurements of in vitro DNA-binding affinity. Together, these results shed new light on the mechanisms by which missense mutations in DNA-binding domains of transcription factors can lead to autosomal dominant diseases.
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Affiliation(s)
- Kevin R Gillinder
- Cancer Genomics Group, Mater Research Institute - University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
| | - Melissa D Ilsley
- Cancer Genomics Group, Mater Research Institute - University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
| | | | - Ravi Sachidanandam
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, NY, USA
| | - Mathieu Lajoie
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, Australia
| | - Graham W Magor
- Cancer Genomics Group, Mater Research Institute - University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
| | - Michael R Tallack
- Cancer Genomics Group, Mater Research Institute - University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
| | - Timothy Bailey
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, NV, USA
| | - Michael J Landsberg
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
| | - Joel P Mackay
- School of Life and Environmental Sciences, The University of Sydney, NSW, Australia
| | - Michael W Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia.,ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Melbourne, VIC, Australia
| | - Luke A Miles
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia
| | | | | | - James J Bieker
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY, USA
| | - Andrew C Perkins
- Cancer Genomics Group, Mater Research Institute - University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia.,Princess Alexandra Hospital, Brisbane, QLD 4102, Australia
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11
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Planutis A, Xue L, Trainor CD, Dangeti M, Gillinder K, Siatecka M, Nebor D, Peters LL, Perkins AC, Bieker JJ. Neomorphic effects of the neonatal anemia (Nan-Eklf) mutation contribute to deficits throughout development. Development 2017; 144:430-440. [PMID: 28143845 DOI: 10.1242/dev.145656] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/18/2016] [Indexed: 12/20/2022]
Abstract
Transcription factor control of cell-specific downstream targets can be significantly altered when the controlling factor is mutated. We show that the semi-dominant neonatal anemia (Nan) mutation in the EKLF/KLF1 transcription factor leads to ectopic expression of proteins that are not normally expressed in the red blood cell, leading to systemic effects that exacerbate the intrinsic anemia in the adult and alter correct development in the early embryo. Even when expressed as a heterozygote, the Nan-EKLF protein accomplishes this by direct binding and aberrant activation of genes encoding secreted factors that exert a negative effect on erythropoiesis and iron use. Our data form the basis for a novel mechanism of physiological deficiency that is relevant to human dyserythropoietic anemia and likely other disease states.
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Affiliation(s)
- Antanas Planutis
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Li Xue
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Cecelia D Trainor
- Laboratory of Molecular Biology, NIDDK, NIH, Bethesda, MD 20892, USA
| | - Mohan Dangeti
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Kevin Gillinder
- Mater Research Institute, University of Queensland, Woolloongabba QLD 4102, Queensland, Australia
| | - Miroslawa Siatecka
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA.,Department of Genetics, University of Adam Mickiewicz, Poznan 61-614, Poland
| | | | | | - Andrew C Perkins
- Mater Research Institute, University of Queensland, Woolloongabba QLD 4102, Queensland, Australia.,Princess Alexandra Hospital, Brisbane QLD 4102, Queensland, Australia
| | - James J Bieker
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA .,Black Family Stem Cell Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.,Tisch Cancer Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.,Mindich Child Health and Development Institute, Mount Sinai School of Medicine, New York, NY 10029, USA
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12
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Yien YY, Bieker JJ. EKLF/KLF1, a tissue-restricted integrator of transcriptional control, chromatin remodeling, and lineage determination. Mol Cell Biol 2013; 33:4-13. [PMID: 23090966 PMCID: PMC3536305 DOI: 10.1128/mcb.01058-12] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Erythroid Krüppel-like factor (EKLF or KLF1) is a transcriptional regulator that plays a critical role in lineage-restricted control of gene expression. KLF1 expression and activity are tightly controlled in a temporal and differentiation stage-specific manner. The mechanisms by which KLF1 is regulated encompass a range of biological processes, including control of KLF1 RNA transcription, protein stability, localization, and posttranslational modifications. Intact KLF1 regulation is essential to correctly regulate erythroid function by gene transcription and to maintain hematopoietic lineage homeostasis by ensuring a proper balance of erythroid/megakaryocytic differentiation. In turn, KLF1 regulates erythroid biology by a wide variety of mechanisms, including gene activation and repression by regulation of chromatin configuration, transcriptional initiation and elongation, and localization of gene loci to transcription factories in the nucleus. An extensive series of biochemical, molecular, and genetic analyses has uncovered some of the secrets of its success, and recent studies are highlighted here. These reveal a multilayered set of control mechanisms that enable efficient and specific integration of transcriptional and epigenetic controls and that pave the way for proper lineage commitment and differentiation.
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Affiliation(s)
- Yvette Y. Yien
- Department of Developmental and Regenerative Biology
- Graduate School of Biological Sciences
| | - James J. Bieker
- Department of Developmental and Regenerative Biology
- Black Family Stem Cell Institute
- Tisch Cancer Institute, Mount Sinai School of Medicine, New York, New York, USA
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13
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Abstract
The cellular events that lead to terminal erythroid differentiation rely on the controlled interplay of extra- and intracellular regulatory factors. Their downstream effects are highly coordinated and result in the structural/morphologic and metabolic changes that uniquely characterize a maturing red blood cell. Erythroid Krüppel-like factor (EKLF/KLF1) is one of a very small number of intrinsic transcription factors that play a major role in regulating these events. This review covers 3 major aspects of erythropoiesis in which EKLF plays crucial functions: (1) at the megakaryocyte-erythroid progenitor stage, where it is involved in erythroid lineage commitment; (2) during the global expansion of erythroid gene expression in primitive and definitive lineages, where it plays a direct role in globin switching; and (3) during the terminal maturation of red cells, where it helps control exit from the cell cycle. We conclude by describing recent studies of mammalian EKLF/KLF1 mutations that lead to altered red cell phenotypes and disease.
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Affiliation(s)
- Miroslawa Siatecka
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY, USA
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14
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Heruth DP, Hawkins T, Logsdon DP, Gibson MI, Sokolovsky IV, Nsumu NN, Major SL, Fegley B, Woods GM, Lewing KB, Neville KA, Cornetta K, Peterson KR, White RA. Mutation in erythroid specific transcription factor KLF1 causes Hereditary Spherocytosis in the Nan hemolytic anemia mouse model. Genomics 2010; 96:303-7. [PMID: 20691777 PMCID: PMC6390478 DOI: 10.1016/j.ygeno.2010.07.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 12/17/2022]
Abstract
KLF1 regulates definitive erythropoiesis of red blood cells by facilitating transcription through high affinity binding to CACCC elements within its erythroid specific target genes including those encoding erythrocyte membrane skeleton (EMS) proteins. Deficiencies of EMS proteins in humans lead to the hemolytic anemia Hereditary Spherocytosis (HS) which includes a subpopulation with no known genetic defect. Here we report that a mutation, E339D, in the second zinc finger domain of KLF1 is responsible for HS in the mouse model Nan. The causative nature of this mutation was verified with an allelic test cross between Nan/+ and heterozygous Klf1(+/-) knockout mice. Homology modeling predicted Nan KLF1 binds CACCC elements more tightly, suggesting that Nan KLF1 is a competitive inhibitor of wild-type KLF1. This is the first association of a KLF1 mutation with a disease state in adult mammals and also presents the possibility of being another causative gene for HS in humans.
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Affiliation(s)
- Daniel P. Heruth
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, 2411 Holmes Street, Kansas City, MO 64108
| | - Troy Hawkins
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, 980 W. Walnut Street, Indianapolis, IN 46202
| | - Derek P. Logsdon
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
| | - Margaret I. Gibson
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
| | - Inna V. Sokolovsky
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
| | - Ndona N. Nsumu
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
| | - Stephanie L. Major
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
| | - Barbara Fegley
- Electron Microscopy Research Laboratory, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160
| | - Gerald M. Woods
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, 2411 Holmes Street, Kansas City, MO 64108
| | - Karen B. Lewing
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, 2411 Holmes Street, Kansas City, MO 64108
| | - Kathleen A. Neville
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, 2411 Holmes Street, Kansas City, MO 64108
| | - Kenneth Cornetta
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, 980 W. Walnut Street, Indianapolis, IN 46202
| | - Kenneth R. Peterson
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160
| | - Robert A. White
- Department of Pediatrics, Children’s Mercy Hospitals & Clinics, 2401 Gillham Road, Kansas City, MO 64108
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, 2411 Holmes Street, Kansas City, MO 64108
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15
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Severe anemia in the Nan mutant mouse caused by sequence-selective disruption of erythroid Kruppel-like factor. Proc Natl Acad Sci U S A 2010; 107:15151-6. [PMID: 20696915 DOI: 10.1073/pnas.1004996107] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Studies of mouse models of anemia have long provided fundamental insights into red blood cell formation and function. Here we show that the semidominant mouse mutation Nan ("neonatal anemia") carries a single amino acid change (E339D) within the second zinc finger of the erythroid Krüppel-like factor (EKLF), a critical erythroid regulatory transcription factor. The mutation alters the DNA-binding specificity of EKLF so that it no longer binds promoters of a subset of its DNA targets. Remarkably, even when mutant Nan and wild-type EKLF alleles are expressed at equivalent levels, the mutant form selectively interferes with expression of EKLF target genes whose promoter elements it no longer binds. This interference yields a distorted genetic output and selective protein deficiencies that differ from those seen in EKLF-heterozygous and EKLF-null red blood cells and presents a unique and unexpected mechanism of inherited disease.
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