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Cheng YHH, Bohaczuk SC, Stergachis AB. Functional categorization of gene regulatory variants that cause Mendelian conditions. Hum Genet 2024; 143:559-605. [PMID: 38436667 PMCID: PMC11078748 DOI: 10.1007/s00439-023-02639-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 12/30/2023] [Indexed: 03/05/2024]
Abstract
Much of our current understanding of rare human diseases is driven by coding genetic variants. However, non-coding genetic variants play a pivotal role in numerous rare human diseases, resulting in diverse functional impacts ranging from altered gene regulation, splicing, and/or transcript stability. With the increasing use of genome sequencing in clinical practice, it is paramount to have a clear framework for understanding how non-coding genetic variants cause disease. To this end, we have synthesized the literature on hundreds of non-coding genetic variants that cause rare Mendelian conditions via the disruption of gene regulatory patterns and propose a functional classification system. Specifically, we have adapted the functional classification framework used for coding variants (i.e., loss-of-function, gain-of-function, and dominant-negative) to account for features unique to non-coding gene regulatory variants. We identify that non-coding gene regulatory variants can be split into three distinct categories by functional impact: (1) non-modular loss-of-expression (LOE) variants; (2) modular loss-of-expression (mLOE) variants; and (3) gain-of-ectopic-expression (GOE) variants. Whereas LOE variants have a direct corollary with coding loss-of-function variants, mLOE and GOE variants represent disease mechanisms that are largely unique to non-coding variants. These functional classifications aim to provide a unified terminology for categorizing the functional impact of non-coding variants that disrupt gene regulatory patterns in Mendelian conditions.
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Affiliation(s)
- Y H Hank Cheng
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Stephanie C Bohaczuk
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Andrew B Stergachis
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA.
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA.
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2
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Steinhaus R, Robinson PN, Seelow D. FABIAN-variant: predicting the effects of DNA variants on transcription factor binding. Nucleic Acids Res 2022; 50:W322-W329. [PMID: 35639768 PMCID: PMC9252790 DOI: 10.1093/nar/gkac393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/22/2022] [Accepted: 05/06/2022] [Indexed: 12/03/2022] Open
Abstract
While great advances in predicting the effects of coding variants have been made, the assessment of non-coding variants remains challenging. This is especially problematic for variants within promoter regions which can lead to over-expression of a gene or reduce or even abolish its expression. The binding of transcription factors to the DNA can be predicted using position weight matrices (PWMs). More recently, transcription factor flexible models (TFFMs) have been introduced and shown to be more accurate than PWMs. TFFMs are based on hidden Markov models and can account for complex positional dependencies. Our new web-based application FABIAN-variant uses 1224 TFFMs and 3790 PWMs to predict whether and to which degree DNA variants affect the binding of 1387 different human transcription factors. For each variant and transcription factor, the software combines the results of different models for a final prediction of the resulting binding-affinity change. The software is written in C++ for speed but variants can be entered through a web interface. Alternatively, a VCF file can be uploaded to assess variants identified by high-throughput sequencing. The search can be restricted to variants in the vicinity of candidate genes. FABIAN-variant is available freely at https://www.genecascade.org/fabian/.
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Affiliation(s)
- Robin Steinhaus
- Exploratory Diagnostic Sciences, Berlin Institute of Health, 10117 Berlin, Germany.,Institute of Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
| | - Peter N Robinson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06030, USA.,Institute for Systems Genomics, University of Connecticut, Farmington, CT 06030, USA
| | - Dominik Seelow
- Exploratory Diagnostic Sciences, Berlin Institute of Health, 10117 Berlin, Germany.,Institute of Medical Genetics and Human Genetics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany
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3
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Russo R, Marra R, Rosato BE, Iolascon A, Andolfo I. Genetics and Genomics Approaches for Diagnosis and Research Into Hereditary Anemias. Front Physiol 2020; 11:613559. [PMID: 33414725 PMCID: PMC7783452 DOI: 10.3389/fphys.2020.613559] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/03/2020] [Indexed: 01/19/2023] Open
Abstract
The hereditary anemias are a relatively heterogeneous set of disorders that can show wide clinical and genetic heterogeneity, which often hampers correct clinical diagnosis. The classical diagnostic workflow for these conditions generally used to start with analysis of the family and personal histories, followed by biochemical and morphological evaluations, and ending with genetic testing. However, the diagnostic framework has changed more recently, and genetic testing is now a suitable approach for differential diagnosis of these patients. There are several approaches to this genetic testing, the choice of which depends on phenotyping, genetic heterogeneity, and gene size. For patients who show complete phenotyping, single-gene testing remains recommended. However, genetic analysis now includes next-generation sequencing, which is generally based on custom-designed targeting panels and whole-exome sequencing. The use of next-generation sequencing also allows the identification of new causative genes, and of polygenic conditions and genetic factors that modify disease severity of hereditary anemias. In the research field, whole-genome sequencing is useful for the identification of non-coding causative mutations, which might account for the disruption of transcriptional factor occupancy sites and cis-regulatory elements. Moreover, advances in high-throughput sequencing techniques have now resulted in the identification of genome-wide profiling of the chromatin structures known as the topologically associating domains. These represent a recurrent disease mechanism that exposes genes to inappropriate regulatory elements, causing errors in gene expression. This review focuses on the challenges of diagnosis and research into hereditary anemias, with indications of both the advantages and disadvantages. Finally, we consider the future perspectives for the use of next-generation sequencing technologies in this era of precision medicine.
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Affiliation(s)
- Roberta Russo
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.,CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Roberta Marra
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.,CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Barbara Eleni Rosato
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.,CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Achille Iolascon
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.,CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Immacolata Andolfo
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.,CEINGE Biotecnologie Avanzate, Naples, Italy
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4
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Gupta H, Chandratre K, Sinha S, Huang T, Wu X, Cui J, Zhang MQ, Wang SM. Highly diversified core promoters in the human genome and their effects on gene expression and disease predisposition. BMC Genomics 2020; 21:842. [PMID: 33256598 PMCID: PMC7706239 DOI: 10.1186/s12864-020-07222-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 11/09/2020] [Indexed: 12/14/2022] Open
Abstract
Background Core promoter controls transcription initiation. However, little is known for core promoter diversity in the human genome and its relationship with diseases. We hypothesized that as a functional important component in the genome, the core promoter in the human genome could be under evolutionary selection, as reflected by its highly diversification in order to adjust gene expression for better adaptation to the different environment. Results Applying the “Exome-based Variant Detection in Core-promoters” method, we analyzed human core-promoter diversity by using the 2682 exome data sets of 25 worldwide human populations sequenced by the 1000 Genome Project. Collectively, we identified 31,996 variants in the core promoter region (− 100 to + 100) of 12,509 human genes (https://dbhcpd.fhs.um.edu.mo). Analyzing the rich variation data identified highly ethnic-specific patterns of core promoter variation between different ethnic populations, the genes with highly variable core promoters, the motifs affected by the variants, and their involved functional pathways. eQTL test revealed that 12% of core promoter variants can significantly alter gene expression level. Comparison with GWAS data we located 163 variants as the GWAS identified traits associated with multiple diseases, half of these variants can alter gene expression. Conclusion Data from our study reals the highly diversified nature of core promoter in the human genome, and highlights that core promoter variation could play important roles not only in gene expression regulation but also in disease predisposition. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-020-07222-5.
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Affiliation(s)
- Hemant Gupta
- Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, SAR, China
| | - Khyati Chandratre
- Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, SAR, China
| | - Siddharth Sinha
- Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, SAR, China
| | - Teng Huang
- Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, SAR, China
| | - Xiaobing Wu
- Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, SAR, China
| | - Jian Cui
- Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Michael Q Zhang
- Department of Biological Sciences, Center for Systems Biology, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - San Ming Wang
- Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau, SAR, China.
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5
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Bianchi P, Fermo E. Molecular heterogeneity of pyruvate kinase deficiency. Haematologica 2020; 105:2218-2228. [PMID: 33054047 PMCID: PMC7556514 DOI: 10.3324/haematol.2019.241141] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/03/2020] [Indexed: 01/19/2023] Open
Abstract
Red cell pyruvate kinase (PK) deficiency is the most common glycolytic defect associated with congenital non-spherocytic hemolytic anemia. The disease, transmitted as an autosomal recessive trait, is caused by mutations in the PKLR gene and is characterized by molecular and clinical heterogeneity; anemia ranges from mild or fully compensated hemolysis to life-threatening forms necessitating neonatal exchange transfusions and/or subsequent regular transfusion support; complications include gallstones, pulmonary hypertension, extramedullary hematopoiesis and iron overload. Since identification of the first pathogenic variants responsible for PK deficiency in 1991, more than 300 different variants have been reported, and the study of molecular mechanisms and the existence of genotype-phenotype correlations have been investigated in-depth. In recent years, during which progress in genetic analysis, next-generation sequencing technologies and personalized medicine have opened up important landscapes for diagnosis and study of molecular mechanisms of congenital hemolytic anemias, genotyping has become a prerequisite for accessing new treatments and for evaluating disease state and progression. This review examines the extensive molecular heterogeneity of PK deficiency, focusing on the diagnostic impact of genotypes and new acquisitions on pathogenic non-canonical variants. The recent progress and the weakness in understanding the genotype-phenotype correlation, and its practical usefulness in light of new therapeutic opportunities for PK deficiency are also discussed.
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MESH Headings
- Anemia, Hemolytic, Congenital/diagnosis
- Anemia, Hemolytic, Congenital/genetics
- Anemia, Hemolytic, Congenital/therapy
- Anemia, Hemolytic, Congenital Nonspherocytic/diagnosis
- Anemia, Hemolytic, Congenital Nonspherocytic/genetics
- Humans
- Mutation
- Pyruvate Kinase/deficiency
- Pyruvate Kinase/genetics
- Pyruvate Metabolism, Inborn Errors/diagnosis
- Pyruvate Metabolism, Inborn Errors/genetics
- Pyruvate Metabolism, Inborn Errors/therapy
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Affiliation(s)
- Paola Bianchi
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, UOC Ematologia, UOS Fisiopatologia delle Anemie, Milan, Italy.
| | - Elisa Fermo
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, UOC Ematologia, UOS Fisiopatologia delle Anemie, Milan, Italy
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6
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Transcriptional States and Chromatin Accessibility Underlying Human Erythropoiesis. Cell Rep 2020; 27:3228-3240.e7. [PMID: 31189107 PMCID: PMC6579117 DOI: 10.1016/j.celrep.2019.05.046] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/03/2019] [Accepted: 05/14/2019] [Indexed: 02/01/2023] Open
Abstract
Human erythropoiesis serves as a paradigm of physiologic cellular differentiation. This process is also of considerable interest for better understanding anemias and identifying new therapies. Here, we apply deep transcriptomic and accessible chromatin profiling to characterize a faithful ex vivo human erythroid differentiation system from hematopoietic stem and progenitor cells. We reveal stage-specific transcriptional states and chromatin accessibility during various stages of erythropoiesis, including 14,260 differentially expressed genes and 63,659 variably accessible chromatin peaks. Our analysis suggests differentiation stage-predominant roles for specific master regulators, including GATA1 and KLF1. We integrate chromatin profiles with common and rare genetic variants associated with erythroid cell traits and diseases, finding that variants regulating different erythroid phenotypes likely act at variable points during differentiation. In addition, we identify a regulator of terminal erythropoiesis, TMCC2, more broadly illustrating the value of this comprehensive analysis to improve our understanding of erythropoiesis in health and disease. Ludwig et al. chart the dynamic transcriptional and chromatin landscapes as hematopoietic stem and progenitor cells differentiate into mature red blood cells. This multi-omic profiling reveals dynamic transcription factor activities and human genetic variation that modulate this process.
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7
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Ling T, Crispino JD. GATA1 mutations in red cell disorders. IUBMB Life 2019; 72:106-118. [PMID: 31652397 DOI: 10.1002/iub.2177] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/18/2019] [Indexed: 01/01/2023]
Abstract
GATA1 is an essential regulator of erythroid cell gene expression and maturation. In its absence, erythroid progenitors are arrested in differentiation and undergo apoptosis. Much has been learned about GATA1 function through animal models, which include genetic knockouts as well as ones with decreased levels of expression. However, even greater insights have come from the finding that a number of rare red cell disorders, including Diamond-Blackfan anemia, are associated with GATA1 mutations. These mutations affect the amino-terminal zinc finger (N-ZF) and the amino-terminus of the protein, and in both cases can alter the DNA-binding activity, which is primarily conferred by the third functional domain, the carboxyl-terminal zinc finger (C-ZF). Here we discuss the role of GATA1 in erythropoiesis with an emphasis on the mutations found in human patients with red cell disorders.
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Affiliation(s)
- Te Ling
- Division of Hematology/Oncology, Northwestern University, Chicago, Illinois
| | - John D Crispino
- Division of Hematology/Oncology, Northwestern University, Chicago, Illinois
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8
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Bao EL, Cheng AN, Sankaran VG. The genetics of human hematopoiesis and its disruption in disease. EMBO Mol Med 2019; 11:e10316. [PMID: 31313878 PMCID: PMC6685084 DOI: 10.15252/emmm.201910316] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 12/25/2022] Open
Abstract
Hematopoiesis, or the process of blood cell production, is a paradigm of multi-lineage cellular differentiation that has been extensively studied, yet in many aspects remains incompletely understood. Nearly all clinically measured hematopoietic traits exhibit extensive variation and are highly heritable, underscoring the importance of genetic variation in these processes. This review explores how human genetics have illuminated our understanding of hematopoiesis in health and disease. The study of rare mutations in blood and immune disorders has elucidated novel roles for regulators of hematopoiesis and uncovered numerous important molecular pathways, as seen through examples such as Diamond-Blackfan anemia and the GATA2 deficiency syndromes. Additionally, population studies of common genetic variation have revealed mechanisms by which human hematopoiesis can be modulated. We discuss advances in functionally characterizing common variants associated with blood cell traits and discuss therapeutic insights, such as the discovery of BCL11A as a modulator of fetal hemoglobin expression. Finally, as genetic techniques continue to evolve, we discuss the prospects, challenges, and unanswered questions that lie ahead in this burgeoning field.
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Affiliation(s)
- Erik L Bao
- Division of Hematology/OncologyBoston Children's HospitalHarvard Medical SchoolBostonMAUSA
- Department of Pediatric OncologyDana‐Farber Cancer InstituteHarvard Medical SchoolBostonMAUSA
- Broad Institute of MIT and HarvardCambridgeMAUSA
- Harvard‐MIT Health Sciences and TechnologyHarvard Medical SchoolBostonMAUSA
| | - Aaron N Cheng
- Division of Hematology/OncologyBoston Children's HospitalHarvard Medical SchoolBostonMAUSA
- Department of Pediatric OncologyDana‐Farber Cancer InstituteHarvard Medical SchoolBostonMAUSA
- Broad Institute of MIT and HarvardCambridgeMAUSA
| | - Vijay G Sankaran
- Division of Hematology/OncologyBoston Children's HospitalHarvard Medical SchoolBostonMAUSA
- Department of Pediatric OncologyDana‐Farber Cancer InstituteHarvard Medical SchoolBostonMAUSA
- Broad Institute of MIT and HarvardCambridgeMAUSA
- Harvard Stem Cell InstituteCambridgeMAUSA
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9
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The molecular genetic background leading to the formation of the human erythroid-specific Xg a/CD99 blood groups. Blood Adv 2019; 2:1854-1864. [PMID: 30061310 DOI: 10.1182/bloodadvances.2018018879] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/02/2018] [Indexed: 02/08/2023] Open
Abstract
The Xga and CD99 antigens of the human Xg blood group system show a unique and sex-specific phenotypic relationship. The phenotypic relationship is believed to result from transcriptional coregulation of the XG and CD99 genes, which span the pseudoautosomal boundary of the X and Y chromosomes. However, the molecular genetic background responsible for these blood groups has remained undetermined. During the present investigation, we initially conducted a pilot study aimed at individuals with different Xga/CD99 phenotypes; this used targeted next-generation sequencing of the genomic areas relevant to XG and CD99 This was followed by a large-scale association study that demonstrated a definite association between a single nucleotide polymorphism (SNP) rs311103 and the Xga/CD99 blood groups. The G and C genotypes of SNP rs311103 were associated with the Xg(a+)/CD99H and Xg(a-)/CD99L phenotypes, respectively. The rs311103 genomic region with the G genotype was found to have stronger transcription-enhancing activity by reporter assay, and this occurred specifically with erythroid-lineage cells. Such activity was absent when the same region with the C genotype was investigated. In silico analysis of the polymorphic rs311103 genomic regions revealed that a binding motif for members of the GATA transcription factor family was present in the rs311103[G] region. Follow-up investigations showed that the erythroid GATA1 factor is able to bind specifically to the rs311103[G] region and markedly stimulates the transcriptional activity of the rs311103[G] segment. The present findings identify the genetic basis of the erythroid-specific Xga/CD99 blood group phenotypes and reveal the molecular background of their formation.
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10
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Barbarani G, Fugazza C, Strouboulis J, Ronchi AE. The Pleiotropic Effects of GATA1 and KLF1 in Physiological Erythropoiesis and in Dyserythropoietic Disorders. Front Physiol 2019; 10:91. [PMID: 30809156 PMCID: PMC6379452 DOI: 10.3389/fphys.2019.00091] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/25/2019] [Indexed: 01/19/2023] Open
Abstract
In the last few years, the advent of new technological approaches has led to a better knowledge of the ontogeny of erythropoiesis during development and of the journey leading from hematopoietic stem cells (HSCs) to mature red blood cells (RBCs). Our view of a well-defined hierarchical model of hematopoiesis with a near-homogeneous HSC population residing at the apex has been progressively challenged in favor of a landscape where HSCs themselves are highly heterogeneous and lineages separate earlier than previously thought. The coordination of these events is orchestrated by transcription factors (TFs) that work in a combinatorial manner to activate and/or repress their target genes. The development of next generation sequencing (NGS) has facilitated the identification of pathological mutations involving TFs underlying hematological defects. The examples of GATA1 and KLF1 presented in this review suggest that in the next few years the number of TF mutations associated with dyserythropoietic disorders will further increase.
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Affiliation(s)
- Gloria Barbarani
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi Milano-Bicocca, Milan, Italy
| | - Cristina Fugazza
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi Milano-Bicocca, Milan, Italy
| | - John Strouboulis
- School of Cancer & Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King's College London, London, United Kingdom
| | - Antonella E Ronchi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi Milano-Bicocca, Milan, Italy
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11
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Svidnicki MCCM, Santos A, Fernandez JAA, Yokoyama APH, Magalhães IQ, Pinheiro VRP, Brandalise SR, Silveira PAA, Costa FF, Saad STO. Novel mutations associated with pyruvate kinase deficiency in Brazil. Rev Bras Hematol Hemoter 2017. [PMID: 29519373 PMCID: PMC6003125 DOI: 10.1016/j.bjhh.2017.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Pyruvate kinase deficiency is a hereditary disease that affects the glycolytic pathway of the red blood cell, causing nonspherocytic hemolytic anemia. The disease is transmitted as an autosomal recessive trait and shows a marked variability in clinical expression. This study reports on the molecular characterization of ten Brazilian pyruvate kinase-deficient patients and the genotype-phenotype correlations. METHOD Sanger sequencing and in silico analysis were carried out to identify and characterize the genetic mutations. A non-affected group of Brazilian individuals were also screened for the most commonly reported variants (c.1456C>T and c.1529G>A). RESULTS Ten different variants were identified in the PKLR gene, of which three are reported here for the first time: p.Leu61Gln, p.Ala137Val and p.Ala428Thr. All the three missense variants involve conserved amino acids, providing a rationale for the observed enzyme deficiency. The allelic frequency of c.1456C>T was 0.1% and the 1529G>A variant was not found. CONCLUSION This is the first comprehensive report on molecular characterization of pyruvate kinase deficiency from South America. The results allowed us to correlate the severity of the clinical phenotype with the identified variants.
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Affiliation(s)
| | - Andrey Santos
- Departamento de Medicina Interna da Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | | | - Ana Paula Hitomi Yokoyama
- Centro de Hematologia e Hemoterapia da Universidade Estadual de Campinas (HEMOCENTRO/UNICAMP), Campinas, SP, Brazil
| | | | - Vitoria Regia Pereira Pinheiro
- Centro Integrado de Pesquisas Onco-Hematológicas na Infância da Universidade Estadual de Campinas (CIPOI/UNICAMP), Campinas, SP, Brazil
| | | | | | - Fernando Ferreira Costa
- Centro de Hematologia e Hemoterapia da Universidade Estadual de Campinas (HEMOCENTRO/UNICAMP), Campinas, SP, Brazil; Departamento de Medicina Interna da Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Sara Teresinha Olalla Saad
- Centro de Hematologia e Hemoterapia da Universidade Estadual de Campinas (HEMOCENTRO/UNICAMP), Campinas, SP, Brazil; Departamento de Medicina Interna da Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil.
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12
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Antoniani C, Romano O, Miccio A. Concise Review: Epigenetic Regulation of Hematopoiesis: Biological Insights and Therapeutic Applications. Stem Cells Transl Med 2017; 6:2106-2114. [PMID: 29080249 PMCID: PMC5702521 DOI: 10.1002/sctm.17-0192] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/28/2017] [Indexed: 12/25/2022] Open
Abstract
Hematopoiesis is the process of blood cell formation starting from hematopoietic stem/progenitor cells (HSPCs). The understanding of regulatory networks involved in hematopoiesis and their impact on gene expression is crucial to decipher the molecular mechanisms that control hematopoietic development in physiological and pathological conditions, and to develop novel therapeutic strategies. An increasing number of epigenetic studies aim at defining, on a genome‐wide scale, the cis‐regulatory sequences (e.g., promoters and enhancers) used by human HSPCs and their lineage‐restricted progeny at different stages of development. In parallel, human genetic studies allowed the discovery of genetic variants mapping to cis‐regulatory elements and associated with hematological phenotypes and diseases. Here, we summarize recent epigenetic and genetic studies in hematopoietic cells that give insights into human hematopoiesis and provide a knowledge basis for the development of novel therapeutic approaches. As an example, we discuss the therapeutic approaches targeting cis‐regulatory regions to reactivate fetal hemoglobin for the treatment of β‐hemoglobinopathies. Epigenetic studies allowed the definition of cis‐regulatory sequences used by human hematopoietic cells. Promoters and enhancers are targeted by transcription factors and are characterized by specific histone modifications. Genetic variants mapping to cis‐regulatory elements are often associated with hematological phenotypes and diseases. In some cases, these variants can alter the binding of transcription factors, thus changing the expression of the target genes. Targeting cis‐regulatory sequences represents a promising therapeutic approach for many hematological diseases. Stem Cells Translational Medicine2017;6:2106–2114
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Affiliation(s)
- Chiara Antoniani
- Laboratory of Chromatin and Gene Regulation During Development, INSERM UMR1163, Imagine Institute, Paris, France.,Paris Descartes, Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Oriana Romano
- Laboratory of Chromatin and Gene Regulation During Development, INSERM UMR1163, Imagine Institute, Paris, France.,Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Annarita Miccio
- Laboratory of Chromatin and Gene Regulation During Development, INSERM UMR1163, Imagine Institute, Paris, France.,Paris Descartes, Sorbonne Paris Cité University, Imagine Institute, Paris, France
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13
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Jaouani M, Manco L, Kalai M, Chaouch L, Douzi K, Silva A, Macedo S, Darragi I, Boudriga I, Chaouachi D, Fitouri Z, Van Wijk R, Ribeiro ML, Abbes S. Molecular basis of pyruvate kinase deficiency among Tunisians: description of new mutations affecting coding and noncoding regions in the PKLR gene. Int J Lab Hematol 2017; 39:223-231. [PMID: 28133914 DOI: 10.1111/ijlh.12610] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/26/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Pyruvate kinase (PK) deficiency is one of the most common hereditary nonspherocytic hemolytic anemias worldwide with clinical manifestations ranging from mild to severe hemolysis. However, investigation of this enzymopathy is lacking in Tunisia. We report here a pioneer investigation of PK deficiency among Tunisian cases referred to our laboratory for biological analysis of unknown cause of hemolytic anemia. METHODS Two hundred and fifty-three patients with unknown cause of hemolytic anemia have been addressed to our laboratory in order to investigate for red blood cells genetic disorders. Red cell enzyme activities were measured by standard methods, and molecular analysis was performed by DNA sequencing. The interpretation of mutation effect and the molecular modeling were performed by using specific software. RESULTS Six different PKLR mutations were found (c.966-1G>T; c.965+1G>A; c.721G>T; c.1163C>A; c.1456C>T; c.1537T>A), among which four are described for the first time. Genotype-phenotype correlations for the novel missense mutations were investigated by three-dimensional structure analysis. CONCLUSION This study provides important data of PK deficiency among Tunisians. It might be followed by a large neonatal screening to determine the spectrum of PK mutations and identify potential deficient patients for an early medical follow-up.
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Affiliation(s)
- M Jaouani
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - L Manco
- Unidade de Hematlogia Molecular, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal.,Research Centre for Anthropology and Health (CIAS), Department of Life Sciences, Universidade de Coimbra, Coimbra, Portugal
| | - M Kalai
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - L Chaouch
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - K Douzi
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - A Silva
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - S Macedo
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - I Darragi
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - I Boudriga
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - D Chaouachi
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Z Fitouri
- Service de pédiatrie-urgences-consultations, Hôpital d'Enfants de Tunis, Tunis, Tunisia
| | - R Van Wijk
- Laboratory for Red Blood Cell Research, Department of Clinical Chemistry and Hematology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M L Ribeiro
- Unidade de Hematlogia Molecular, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
| | - S Abbes
- Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
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14
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Deplancke B, Alpern D, Gardeux V. The Genetics of Transcription Factor DNA Binding Variation. Cell 2016; 166:538-554. [PMID: 27471964 DOI: 10.1016/j.cell.2016.07.012] [Citation(s) in RCA: 244] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Indexed: 12/23/2022]
Abstract
Most complex trait-associated variants are located in non-coding regulatory regions of the genome, where they have been shown to disrupt transcription factor (TF)-DNA binding motifs. Variable TF-DNA interactions are therefore increasingly considered as key drivers of phenotypic variation. However, recent genome-wide studies revealed that the majority of variable TF-DNA binding events are not driven by sequence alterations in the motif of the studied TF. This observation implies that the molecular mechanisms underlying TF-DNA binding variation and, by extrapolation, inter-individual phenotypic variation are more complex than originally anticipated. Here, we summarize the findings that led to this important paradigm shift and review proposed mechanisms for local, proximal, or distal genetic variation-driven variable TF-DNA binding. In addition, we discuss the biomedical implications of these findings for our ability to dissect the molecular role(s) of non-coding genetic variants in complex traits, including disease susceptibility.
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Affiliation(s)
- Bart Deplancke
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
| | - Daniel Alpern
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Vincent Gardeux
- Laboratory of Systems Biology and Genetics, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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15
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Congenital dyserythropoietic anemia associated to a GATA1 mutation aggravated by pyruvate kinase deficiency. Ann Hematol 2016; 95:1551-3. [PMID: 27342114 DOI: 10.1007/s00277-016-2720-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/31/2016] [Indexed: 01/01/2023]
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16
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Ulirsch JC, Nandakumar SK, Wang L, Giani FC, Zhang X, Rogov P, Melnikov A, McDonel P, Do R, Mikkelsen TS, Sankaran VG. Systematic Functional Dissection of Common Genetic Variation Affecting Red Blood Cell Traits. Cell 2016; 165:1530-1545. [PMID: 27259154 PMCID: PMC4893171 DOI: 10.1016/j.cell.2016.04.048] [Citation(s) in RCA: 224] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/12/2015] [Accepted: 04/12/2016] [Indexed: 11/24/2022]
Abstract
Genome-wide association studies (GWAS) have successfully identified thousands of associations between common genetic variants and human disease phenotypes, but the majority of these variants are non-coding, often requiring genetic fine-mapping, epigenomic profiling, and individual reporter assays to delineate potential causal variants. We employ a massively parallel reporter assay (MPRA) to simultaneously screen 2,756 variants in strong linkage disequilibrium with 75 sentinel variants associated with red blood cell traits. We show that this assay identifies elements with endogenous erythroid regulatory activity. Across 23 sentinel variants, we conservatively identified 32 MPRA functional variants (MFVs). We used targeted genome editing to demonstrate endogenous enhancer activity across 3 MFVs that predominantly affect the transcription of SMIM1, RBM38, and CD164. Functional follow-up of RBM38 delineates a key role for this gene in the alternative splicing program occurring during terminal erythropoiesis. Finally, we provide evidence for how common GWAS-nominated variants can disrupt cell-type-specific transcriptional regulatory pathways.
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Affiliation(s)
- Jacob C Ulirsch
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Satish K Nandakumar
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Li Wang
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Felix C Giani
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Charité-Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Xiaolan Zhang
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Peter Rogov
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Patrick McDonel
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Ron Do
- Department of Genetics and Genomic Sciences and The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Tarjei S Mikkelsen
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Vijay G Sankaran
- Division of Hematology/Oncology, The Manton Center for Orphan Disease Research, Boston Children's Hospital and Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
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17
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Safe and Efficient Gene Therapy for Pyruvate Kinase Deficiency. Mol Ther 2016; 24:1187-98. [PMID: 27138040 DOI: 10.1038/mt.2016.87] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 03/25/2016] [Indexed: 12/17/2022] Open
Abstract
Pyruvate kinase deficiency (PKD) is a monogenic metabolic disease caused by mutations in the PKLR gene that leads to hemolytic anemia of variable symptomatology and that can be fatal during the neonatal period. PKD recessive inheritance trait and its curative treatment by allogeneic bone marrow transplantation provide an ideal scenario for developing gene therapy approaches. Here, we provide a preclinical gene therapy for PKD based on a lentiviral vector harboring the hPGK eukaryotic promoter that drives the expression of the PKLR cDNA. This therapeutic vector was used to transduce mouse PKD hematopoietic stem cells (HSCs) that were subsequently transplanted into myeloablated PKD mice. Ectopic RPK expression normalized the erythroid compartment correcting the hematological phenotype and reverting organ pathology. Metabolomic studies demonstrated functional correction of the glycolytic pathway in RBCs derived from genetically corrected PKD HSCs, with no metabolic disturbances in leukocytes. The analysis of the lentiviral insertion sites in the genome of transplanted hematopoietic cells demonstrated no evidence of genotoxicity in any of the transplanted animals. Overall, our results underscore the therapeutic potential of the hPGK-coRPK lentiviral vector and provide high expectations toward the gene therapy of PKD and other erythroid metabolic genetic disorders.
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18
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Kager L, Minkov M, Zeitlhofer P, Fahrner B, Ratzinger F, Boztug K, Dossenbach-Glaninger A, Haas OA. Two Novel Missense Mutations and a 5bp Deletion in the Erythroid-Specific Promoter of the PKLR Gene in Two Unrelated Patients With Pyruvate Kinase Deficient Transfusion-Dependent Chronic Nonspherocytic Hemolytic Anemia. Pediatr Blood Cancer 2016; 63:914-6. [PMID: 26728349 DOI: 10.1002/pbc.25878] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 12/01/2015] [Indexed: 01/19/2023]
Abstract
We report two children with severe chronic hemolytic anemia, the cause of which was difficult to establish because of transfusion dependency. Reduced erythrocyte pyruvate kinase activity in their asymptomatic parents provided the diagnostic clues for mutation screening of the PKLR gene and revealed that one child was a compound heterozygote of a novel paternally derived 5-bp deletion in the promoter region (c.-88_-84delTCTCT) and a maternally derived missense mutation in exon nine (c.1174G>A; p.Ala392Thr). The second child was a compound heterozygote of two novel missense mutations, namely a paternally derived exon ten c.1381G>A (p.Glu461Lys) and a maternally derived exon seven c.907-908delCC (p.Pro303GlyfsX12) variant.
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Affiliation(s)
- Leo Kager
- St. Anna Children's Hospital, Department of Pediatrics, Medical University Vienna.,Children's Cancer Research Institute
| | - Milen Minkov
- St. Anna Children's Hospital, Department of Pediatrics, Medical University Vienna.,Department of Pediatrics, Hospital Rudolfstiftung
| | | | - Bernhard Fahrner
- St. Anna Children's Hospital, Department of Pediatrics, Medical University Vienna
| | - Franz Ratzinger
- Department of Laboratory Medicine, Medical University Vienna
| | - Kaan Boztug
- St. Anna Children's Hospital, Department of Pediatrics, Medical University Vienna.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences
| | | | - Oskar A Haas
- St. Anna Children's Hospital, Department of Pediatrics, Medical University Vienna.,Children's Cancer Research Institute.,medgen.at GmbH
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19
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Insight into GATA1 transcriptional activity through interrogation of cis elements disrupted in human erythroid disorders. Proc Natl Acad Sci U S A 2016; 113:4434-9. [PMID: 27044088 DOI: 10.1073/pnas.1521754113] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Whole-exome sequencing has been incredibly successful in identifying causal genetic variants and has revealed a number of novel genes associated with blood and other diseases. One limitation of this approach is that it overlooks mutations in noncoding regulatory elements. Furthermore, the mechanisms by which mutations in transcriptionalcis-regulatory elements result in disease remain poorly understood. Here we used CRISPR/Cas9 genome editing to interrogate three such elements harboring mutations in human erythroid disorders, which in all cases are predicted to disrupt a canonical binding motif for the hematopoietic transcription factor GATA1. Deletions of as few as two to four nucleotides resulted in a substantial decrease (>80%) in target gene expression. Isolated deletions of the canonical GATA1 binding motif completely abrogated binding of the cofactor TAL1, which binds to a separate motif. Having verified the functionality of these three GATA1 motifs, we demonstrate strong evolutionary conservation of GATA1 motifs in regulatory elements proximal to other genes implicated in erythroid disorders, and show that targeted disruption of such elements results in altered gene expression. By modeling transcription factor binding patterns, we show that multiple transcription factors are associated with erythroid gene expression, and have created predictive maps modeling putative disruptions of their binding sites at key regulatory elements. Our study provides insight into GATA1 transcriptional activity and may prove a useful resource for investigating the pathogenicity of noncoding variants in human erythroid disorders.
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20
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Society for Pediatric Research 2015 Young Investigator Award: genetics of human hematopoiesis-what patients can teach us about blood cell production. Pediatr Res 2016; 79:366-70. [PMID: 26575596 DOI: 10.1038/pr.2015.245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 09/30/2015] [Indexed: 11/09/2022]
Abstract
Blood cell production or hematopoiesis is one of the most well-understood paradigms of cell differentiation in the body. The majority of work on hematopoiesis comes from studies that have primarily been conducted in mice, zebrafish, or other valuable model systems. However, it is clear that such model organisms may not consistently and faithfully mimic what is observed in humans with blood disorders. Moreover, there is significant divergence between species that is increasingly being appreciated at the genomic level. As a result, there is an opportunity to use observations in humans to provide a refined view of hematopoiesis. Here, we discuss vignettes from our work that illustrate how insight from human genetics can improve our understanding of blood cell production and identify promising therapeutic approaches for blood disorders.
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21
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Canu G, De Bonis M, Minucci A, Capoluongo E. Red blood cell PK deficiency: An update of PK-LR gene mutation database. Blood Cells Mol Dis 2016; 57:100-9. [PMID: 26832193 DOI: 10.1016/j.bcmd.2015.12.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/21/2015] [Accepted: 12/29/2015] [Indexed: 11/16/2022]
Abstract
Pyruvate kinase (PK) deficiency is known as being the most common cause of chronic nonspherocytic hemolytic anemia (CNSHA). Clinical PK deficiency is transmitted as an autosomal recessive trait, that can segregate neither in homozygous or in a compound heterozygous modality, respectively. Two PK genes are present in mammals: the pyruvate kinase liver and red blood cells (PK-LR) and the pyruvate kinase muscle (PK-M), of which only the first encodes for the isoenzymes normally expressed in the red blood cells (R-type) and in the liver (L-type). Several reports have been published describing a large variety of genetic defects in PK-LR gene associated to CNSHA. Herein, we present a review of about 250 published mutations and six polymorphisms in PK-LR gene with the corresponding clinical and molecular data. We consulted the PubMed website for searching mutations and papers, along with two main databases: the Leiden Open Variation Database (LOVD, https://grenada.lumc.nl/LOVD2/mendelian_genes/home.php?select_db=PKLR) and Human Gene Mutation Database (HGMD, http://www.hgmd.cf.ac.uk/ac/gene.php?gene=PKLR) for selecting, reviewing and listing the annotated PK-LR gene mutations present in literature. This paper is aimed to provide useful information to clinicians and laboratory professionals regarding overall reported PK-LR gene mutations, also giving the opportunity to harmonize data regarding PK-deficient individuals.
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Affiliation(s)
- Giulia Canu
- Laboratory of Clinical Molecular and Personalized Diagnostics, Department of Laboratory Medicine, "A Gemelli" Hospital, Catholic University, Largo Agostino Gemelli 8, Roma, Italy.
| | - Maria De Bonis
- Laboratory of Clinical Molecular and Personalized Diagnostics, Department of Laboratory Medicine, "A Gemelli" Hospital, Catholic University, Largo Agostino Gemelli 8, Roma, Italy
| | - Angelo Minucci
- Laboratory of Clinical Molecular and Personalized Diagnostics, Department of Laboratory Medicine, "A Gemelli" Hospital, Catholic University, Largo Agostino Gemelli 8, Roma, Italy.
| | - Ettore Capoluongo
- Laboratory of Clinical Molecular and Personalized Diagnostics, Department of Laboratory Medicine, "A Gemelli" Hospital, Catholic University, Largo Agostino Gemelli 8, Roma, Italy
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22
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Campagna DR, de Bie CI, Schmitz-Abe K, Sweeney M, Sendamarai AK, Schmidt PJ, Heeney MM, Yntema HG, Kannengiesser C, Grandchamp B, Niemeyer CM, Knoers NV, Swart S, Marron G, van Wijk R, Raymakers RA, May A, Markianos K, Bottomley SS, Swinkels DW, Fleming MD. X-linked sideroblastic anemia due to ALAS2 intron 1 enhancer element GATA-binding site mutations. Am J Hematol 2014; 89:315-9. [PMID: 24166784 PMCID: PMC3943703 DOI: 10.1002/ajh.23616] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 10/21/2013] [Indexed: 02/06/2023]
Abstract
X-linked sideroblastic anemia (XLSA) is the most common form of congenital sideroblastic anemia. In affected males, it is uniformly associated with partial loss-of-function missense mutations in the erythroid-specific heme biosynthesis protein 5-aminolevulinate synthase 2 (ALAS2). Here, we report five families with XLSA owing to mutations in a GATA transcription factor binding site located in a transcriptional enhancer element in intron 1 of the ALAS2 gene. As such, this study defines a new class of mutations that should be evaluated in patients undergoing genetic testing for a suspected diagnosis of XLSA.
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Affiliation(s)
- Dean R. Campagna
- Department of Pathology, Boston Children's Hospital, Boston, MA, USA
| | - Charlotte I. de Bie
- Department of Medical Genetics, University Medical Centre, Utrecht, Utrecht, the Netherlands
| | - Klaus Schmitz-Abe
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Marion Sweeney
- Department of Haematology, Cardiff University School of Medicine, Heath Park, Cardiff, Wales
| | | | - Paul J. Schmidt
- Department of Pathology, Boston Children's Hospital, Boston, MA, USA
| | | | - Helger G. Yntema
- Department of Genetics, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Caroline Kannengiesser
- Laboratoire de Génétique Moléculaire, Unité fonctionnelle de génétique, Hôpital Xavier Bichat-Claude Bernard, Université Paris Diderot, insermU773, Paris, France
| | - Bernard Grandchamp
- Laboratoire de Génétique Moléculaire, Unité fonctionnelle de génétique, Hôpital Xavier Bichat-Claude Bernard, Université Paris Diderot, insermU773, Paris, France
| | - Charlotte M. Niemeyer
- Children's Hospital, University of Freiburg, Pediatric Hematology and Oncology Department, Freiburg, Germany
| | - Nine V.A.M. Knoers
- Department of Medical Genetics, University Medical Centre, Utrecht, Utrecht, the Netherlands
| | - Sonia Swart
- NGH NHS Trust, Northampton General Hospital, Clifton Ville, Northampton, England
| | - Gordon Marron
- Department of Haematology, Ninewells Hospital, Dundee, DD1 9SY, Scotland
| | - Richard van Wijk
- Department of Clinical Chemistry and Haematology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Reinier A. Raymakers
- Department of Haematology, University Medical Centre, Utrecht, Utrecht, the Netherlands
| | - Alison May
- Department of Haematology, Cardiff University School of Medicine, Heath Park, Cardiff, Wales
| | - Kyriacos Markianos
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Sylvia S. Bottomley
- Department of Medicine, Hematology-Oncology Section, University of Oklahoma College of Medicine, Oklahoma City, OK, USA
| | - Dorine W. Swinkels
- Department of Laboratory Medicine, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Mark D. Fleming
- Department of Pathology, Boston Children's Hospital, Boston, MA, USA
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23
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Nakajima T, Sano R, Takahashi Y, Kubo R, Takahashi K, Kominato Y, Tsukada J, Takeshita H, Yasuda T, Uchikawa M, Isa K, Ogasawara K. Mutation of the GATA site in the erythroid cell-specific regulatory element of the ABO gene in a Bm subgroup individual. Transfusion 2013; 53:2917-27. [PMID: 23560502 DOI: 10.1111/trf.12181] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/29/2013] [Accepted: 02/03/2013] [Indexed: 12/31/2022]
Abstract
BACKGROUND The ABO blood group is important in blood transfusion. Recently, an erythroid cell-specific regulatory element has been identified in the first intron of ABO using luciferase reporter assays with K562 cells. The erythroid cell-specific regulatory activity of the element was dependent upon GATA-1 binding. In addition, partial deletion of Intron 1 including the element was observed in genomic DNAs obtained from 111 Bm and ABm individuals, except for one, whereas the deletion was never found among 1005 individuals with the common phenotypes. STUDY DESIGN AND METHODS In this study, further investigation was performed to reveal the underlying mechanism responsible for reduction of B antigen expression in the exceptional Bm individual. Peptide nucleic acid-clamping polymerase chain reaction was carried out to amplify the B-related allele, followed by sequence determination. Electrophoretic mobility assays and promoter assays were performed to examine whether a nucleotide substitution reduced the binding of a transcription factor and induced loss of function of the element. RESULTS Sequence determination revealed one point mutation of the GATA motif in the element. The electrophoretic mobility shift assays showed that the mutation abolished the binding of GATA transcription factors, and the promoter assays demonstrated complete loss of enhancer activity of the element. CONCLUSION These observations suggest that the mutation in the GATA motif of the erythroid-specific regulatory element may diminish the binding of GATA transcription factors and down regulate transcriptional activity of the element on the B allele, leading to reduction of B antigen expression in erythroid lineage cells of the Bm individual.
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Affiliation(s)
- Tamiko Nakajima
- Department of Legal Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan; Cancer Chemotherapy Center and Hematology, University of Occupational and Environmental Health, Fukuoka, Japan; Department of Legal Medicine, Shimane University School of Medicine, Shimane, Japan; Division of Medical Genetics and Biochemistry, Faculty of Medicine, University of Fukui, Fukui, Japan; Japanese Red Cross Tokyo Blood Center, Tokyo, Japan; Japanese Red Cross Central Blood Institute, Tokyo, Japan
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24
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Jarinova O, Ekker M. Regulatory variations in the era of next-generation sequencing: Implications for clinical molecular diagnostics. Hum Mutat 2012; 33:1021-30. [DOI: 10.1002/humu.22083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 03/06/2012] [Indexed: 01/05/2023]
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25
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Machado P, Pereira R, Rocha AM, Manco L, Fernandes N, Miranda J, Ribeiro L, do Rosário VE, Amorim A, Gusmão L, Arez AP. Malaria: looking for selection signatures in the human PKLR gene region. Br J Haematol 2010; 149:775-84. [PMID: 20377593 DOI: 10.1111/j.1365-2141.2010.08165.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The genetic component of susceptibility to malaria is both complex and multigenic and the better-known protective polymorphisms are those involving erythrocyte-specific structural proteins and enzymes. In vivo and in vitro data have suggested that pyruvate kinase deficiency, which causes a nonspherocytic haemolytic anaemia, could be protective against malaria severity in humans, but this hypothesis remains to be tested. In the present study, we conducted a combined analysis of Short Tandem Repeats (STRs) and Single Nucleotide Polymorphisms (SNPs) in the pyruvate kinase-encoding gene (PKLR) and adjacent regions (chromosome 1q21) to look for malaria selective signatures in two sub-Saharan African populations from Angola and Mozambique, in several groups with different malaria infection outcome. A European population from Portugal, including a control and a pyruvate kinase-deficient group, was used for comparison. Data from STR and SNP loci spread along the PKLR gene region showed a considerably higher differentiation between African and Portuguese populations than that usually found for neutral markers. In addition, a wider region showing strong linkage disequilibrium was found in an uncomplicated malaria group, and a haplotype was found to be associated with this clinical group. Altogether, this data suggests that malaria selective pressure is acting in this genomic region.
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Affiliation(s)
- Patrícia Machado
- Centre for Malaria and Tropical Diseases, Malaria Unit, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal.
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26
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Alves J, Machado P, Silva J, Gonçalves N, Ribeiro L, Faustino P, do Rosário VE, Manco L, Gusmão L, Amorim A, Arez AP. Analysis of malaria associated genetic traits in Cabo Verde, a melting pot of European and sub Saharan settlers. Blood Cells Mol Dis 2009; 44:62-8. [PMID: 19837619 DOI: 10.1016/j.bcmd.2009.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 09/17/2009] [Indexed: 11/16/2022]
Abstract
Malaria has occurred in the Cabo Verde archipelago with epidemic characteristics since its colonization. Nowadays, it occurs in Santiago Island alone and though prophylaxis is not recommended by the World Health Organization, studies have highlight the prospect of malaria becoming a serious public health problem as a result of the presence of antimalarial drug resistance associated with mutations in the parasite populations and underscore the need for tighter surveillance. Despite the presumptive weak immune status of the population, severe symptoms of malaria are not observed and many people present a subclinical course of the disease. No data on the prevalence of sickle-cell trait and red cell glucose-6-phosphate dehydrogenase deficiency (two classical genetic factors associated with resistance to severe malaria) were available for the Cabo Verde archipelago and, therefore, we studied the low morbidity from malaria in relation to the particular genetic characteristics of the human host population. We also included the analysis of the pyruvate kinase deficiency associated gene, reported as putatively associated with resistance to the disease. Allelic frequencies of the polymorphisms examined are closer to European than to African populations and no malaria selection signatures were found. No association was found between the analyzed human factors and infection but one result is of high interest: a linkage disequilibrium test revealed an association of distant loci in the PKLR gene and adjacent regions, only in non-infected individuals. This could mean a more conserved gene region selected in association to protection against the infection and/or the disease.
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Affiliation(s)
- Joana Alves
- Centre for Malaria and Tropical Diseases, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira, 100, 1349-008 Lisbon, Portugal
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27
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Narlikar L, Ovcharenko I. Identifying regulatory elements in eukaryotic genomes. BRIEFINGS IN FUNCTIONAL GENOMICS AND PROTEOMICS 2009; 8:215-30. [PMID: 19498043 DOI: 10.1093/bfgp/elp014] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Proper development and functioning of an organism depends on precise spatial and temporal expression of all its genes. These coordinated expression-patterns are maintained primarily through the process of transcriptional regulation. Transcriptional regulation is mediated by proteins binding to regulatory elements on the DNA in a combinatorial manner, where particular combinations of transcription factor binding sites establish specific regulatory codes. In this review, we survey experimental and computational approaches geared towards the identification of proximal and distal gene regulatory elements in the genomes of complex eukaryotes. Available approaches that decipher the genetic structure and function of regulatory elements by exploiting various sources of information like gene expression data, chromatin structure, DNA-binding specificities of transcription factors, cooperativity of transcription factors, etc. are highlighted. We also discuss the relevance of regulatory elements in the context of human health through examples of mutations in some of these regions having serious implications in misregulation of genes and being strongly associated with human disorders.
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Affiliation(s)
- Leelavati Narlikar
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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de Vooght KMK, van Wijk R, van Solinge WW. Management of gene promoter mutations in molecular diagnostics. Clin Chem 2009; 55:698-708. [PMID: 19246615 DOI: 10.1373/clinchem.2008.120931] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Although promoter mutations are known to cause functionally important consequences for gene expression, promoter analysis is not a regular part of DNA diagnostics. CONTENT This review covers different important aspects of promoter mutation analysis and includes a proposed model procedure for studying promoter mutations. Characterization of a promoter sequence variation includes a comprehensive study of the literature and databases of human mutations and transcription factors. Phylogenetic footprinting is also used to evaluate the putative importance of the promoter region of interest. This in silico analysis is, in general, followed by in vitro functional assays, of which transient and stable transfection assays are considered the gold-standard methods. Electrophoretic mobility shift and supershift assays are used to identify trans-acting proteins that putatively interact with the promoter region of interest. Finally, chromatin immunoprecipitation assays are essential to confirm in vivo binding of these proteins to the promoter. SUMMARY Although promoter mutation analysis is complex, often laborious, and difficult to perform, it is an essential part of the diagnosis of disease-causing promoter mutations and improves our understanding of the role of transcriptional regulation in human disease. We recommend that routine laboratories and research groups specialized in gene promoter research cooperate to expand general knowledge and diagnosis of gene-promoter defects.
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Affiliation(s)
- Karen M K de Vooght
- Department of Clinical Chemistry and Haematology, Laboratory for Red Blood Cell Research, University Medical Center Utrecht, Utrecht, the Netherlands.
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29
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Coutinho R, Bento C, Almeida H, Cunha E, Manco L, Ferreira F, Ribeiro ML. Complex inheritance of chronic haemolytic anaemia. Br J Haematol 2008; 144:615-6. [PMID: 19036089 DOI: 10.1111/j.1365-2141.2008.07479.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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Marcello AP, Vercellati C, Fermo E, Bianchi P, Zaninoni A, Barcellini W, Zanella A. A case of congenital red cell pyruvate kinase deficiency associated with hereditary stomatocytosis. Blood Cells Mol Dis 2008; 41:261-2. [PMID: 18708292 DOI: 10.1016/j.bcmd.2008.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 07/11/2008] [Indexed: 11/29/2022]
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31
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Maston GA, Evans SK, Green MR. Transcriptional regulatory elements in the human genome. Annu Rev Genomics Hum Genet 2008; 7:29-59. [PMID: 16719718 DOI: 10.1146/annurev.genom.7.080505.115623] [Citation(s) in RCA: 539] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The faithful execution of biological processes requires a precise and carefully orchestrated set of steps that depend on the proper spatial and temporal expression of genes. Here we review the various classes of transcriptional regulatory elements (core promoters, proximal promoters, distal enhancers, silencers, insulators/boundary elements, and locus control regions) and the molecular machinery (general transcription factors, activators, and coactivators) that interacts with the regulatory elements to mediate precisely controlled patterns of gene expression. The biological importance of transcriptional regulation is highlighted by examples of how alterations in these transcriptional components can lead to disease. Finally, we discuss the methods currently used to identify transcriptional regulatory elements, and the ability of these methods to be scaled up for the purpose of annotating the entire human genome.
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Affiliation(s)
- Glenn A Maston
- Howard Hughes Medical Institute, Programs in Gene Function and Expression and Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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32
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Zanella A, Fermo E, Bianchi P, Chiarelli LR, Valentini G. Pyruvate kinase deficiency: the genotype-phenotype association. Blood Rev 2007; 21:217-31. [PMID: 17360088 DOI: 10.1016/j.blre.2007.01.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Red cell pyruvate kinase (PK) deficiency is the most frequent enzyme abnormality of glycolysis causing chronic non-spherocytic haemolytic anaemia. The disease is transmitted as an autosomal recessive trait, clinical symptoms usually occurring in compound heterozygotes for two mutant alleles and in homozygotes. The severity of haemolysis is highly variable, ranging from very mild or fully compensated forms to life-threatening neonatal anaemia necessitating exchange transfusions. Erythrocyte PK is synthesised under the control of the PK-LR gene located on chromosome 1. One hundred eighty different mutations in PK-LR gene, mostly missense, have been so far reported associated to PK deficiency. First attempts to delineate the genotype-phenotype association were mainly based on the analysis of the enzyme's three-dimensional structure and the observation of the few homozygous patients. More recently, the comparison of the recombinant mutants of human red cell PK with the wild-type enzyme has enabled the effects of amino acid replacements on the enzyme molecular properties to be determined. However, the clinical manifestations of red cell enzyme defects are not merely dependent on the molecular properties of the mutant protein but rather reflect the complex interactions of additional factors, including genetic background, concomitant functional polymorphisms of other enzymes, posttranslational or epigenetic modifications, ineffective erythropoiesis and differences in splenic function.
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Affiliation(s)
- Alberto Zanella
- Department of Haematology, Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Milan, Italy.
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33
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Zanella A, Fermo E, Bianchi P, Valentini G. Red cell pyruvate kinase deficiency: molecular and clinical aspects. Br J Haematol 2005; 130:11-25. [PMID: 15982340 DOI: 10.1111/j.1365-2141.2005.05527.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Red cell pyruvate kinase (PK) deficiency is the most frequent enzyme abnormality of the glycolytic pathway causing hereditary non-spherocytic haemolytic anaemia. The degree of haemolysis varies widely, ranging from very mild or fully compensated forms, to life-threatening neonatal anaemia and jaundice necessitating exchange transfusions. Erythrocyte PK is synthesized under the control of the PK-LR gene located on chromosome 1. To date, more than 150 different mutations in the PK-LR gene have been associated with PK deficiency. First attempts to delineate the biochemical and clinical consequences of the molecular defect were mainly based on the observation of the few homozygous patients and on the analysis of the three-dimensional structure of the enzyme. More recently, the comparison of the recombinant mutants of human red cell PK with the wild-type enzyme has enabled the effects of amino acid replacements on the enzyme molecular properties to be determined and help to correlate genotype to clinical phenotype.
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Affiliation(s)
- Alberto Zanella
- Department of Haematology, IRCCS Ospedale Maggiore, Milan, Italy.
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34
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Fermo E, Bianchi P, Chiarelli LR, Cotton F, Vercellati C, Writzl K, Baker K, Hann I, Rodwell R, Valentini G, Zanella A. Red cell pyruvate kinase deficiency: 17 new mutations of the PK-LR gene. Br J Haematol 2005; 129:839-46. [PMID: 15953013 DOI: 10.1111/j.1365-2141.2005.05520.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The PK-LR gene was studied in 23 patients with congenital haemolytic anaemia associated with erythrocyte pyruvate kinase (PK) deficiency. Twenty-seven different mutations were detected among the 42 mutated alleles identified: 19 missense mutations, four splice site mutations and one nonsense, one single base deletion and two large deletions. Seventeen of them (107G, 278T, 403T, 409A, 661A, 859C, 958A, 1094T, 1190T, 1209A, 1232C, 1369G, 507A, IVS9 -1c, IVS9 +43c [corrected] del C224, del 5006bp IVS3--> nt 1431) were new. Although all the exons, the flanking regions and the promoter were sequenced in all cases, we failed to detect the second expected mutation in four subjects. To correlate genotype to phenotype, the molecular results were related to the biochemical properties of the mutant enzymes by an analysis of the three-dimensional structure of erythrocyte PK. The new mutant 409A, found in association with the large deletion of 5006 bp in a newborn baby who died soon after birth, was functionally characterized by mutagenesis and in vitro expression of the protein to investigate its contribution in the severity of the clinical pattern. However, the biochemical data obtained for the mutant enzyme cannot explain the severe anaemia found in the PK-deficient patient hemizygous for this mutation.
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Affiliation(s)
- Elisa Fermo
- Dipartimento di Ematologia, IRCCS Ospedale Maggiore di Milano, Milan, Italy
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35
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Diez A, Gilsanz F, Martinez J, Pérez-Benavente S, Meza NW, Bautista JM. Life-threatening nonspherocytic hemolytic anemia in a patient with a null mutation in the PKLR gene and no compensatory PKM gene expression. Blood 2005; 106:1851-6. [PMID: 15870173 DOI: 10.1182/blood-2005-02-0555] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractHuman erythrocyte R-type pyruvate kinase (RPK) deficiency is an autosomal recessive disorder produced by mutations in the PKLR gene, causing chronic nonspherocytic hemolytic anemia. Survival of patients with severe RPK deficiency has been associated with compensatory expression in red blood cells (RBCs) of M2PK, an isoenzyme showing wide tissue distribution. We describe a novel homozygous null mutation of the PKLR gene found in a girl with a prenatal diagnosis of PK deficiency. The mutant PK gene revealed an 11-nucleotide (nt) duplication at exon 8, causing frameshift of the PKLR transcript, predicting a truncated protein inferred to have no catalytic activity. Western blot analysis and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) detected no M2PK expression in the peripheral blood red cell fraction. The expression of mutant RPK mRNA in the RBCs was almost 6 times higher than that detected in a control patient with hereditary spherocytosis. This molecular phenotypic analysis of the null mutation in the PKLR gene provides evidence for a lack of M2PK in the mature RBCs of this patient and suggests that normal red cell functions and survival are achieved through a population of young erythroid cells released into the circulation in response to anemia. (Blood. 2005;106:1851-1856)
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Affiliation(s)
- Amalia Diez
- Departamento de Bioquímica y Biología Molecular IV, Universidad Complutense de Madrid, Spain
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36
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Wijk R, van Wesel ACW, Thomas AAM, Rijksen G, van Solinge WW. Ex vivoanalysis of aberrant splicing induced by two donor site mutations inPKLRof a patient with severe pyruvate kinase deficiency. Br J Haematol 2004; 125:253-63. [PMID: 15059150 DOI: 10.1111/j.1365-2141.2004.04895.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two single-nucleotide substitutions in PKLR constituted the molecular basis underlying pyruvate kinase (PK) deficiency in a patient with severe haemolytic anaemia. One novel mutation, IVS5+1G>A, abolished the intron 5 donor splice site. The other mutation, c.1436G>A, altered the intron 10 donor splice site consensus sequence and, moreover, encoded an R479H substitution. We studied the effects on PKLR pre-mRNA processing, using ex vivo-produced nucleated erythroid cells from the patient. Abolition of the intron 5 splice site initiated two events in the majority of transcripts: skipping of exon 5 or, surprisingly, simultaneous skipping of exon 5 and 6 (Delta5,6). Subcellular localization of transcripts suggested that no functional protein was produced by the IVS5+1A allele. The unusual Delta5,6 transcript suggests that efficient inclusion of exon 6 in wild-type PKLR mRNA depends on the presence of splice-enhancing elements in exon 5. The c.1436G>A mutation caused skipping of exon 10 but was mainly associated with a severe reduction in transcripts although these were, in general, normally processed. Accordingly, low amounts of PK were detected in nucleated erythroid cells of the patient, thus correlating with the patient's PK-deficient phenotype. Finally, several low-abundant transcripts were detected that represent the first examples of "leaky-splicing" in PKLR.
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Affiliation(s)
- Richard Wijk
- Department of Clinical Chemistry, University Medical Centre Utrecht, 3508 GA Utrecht, The Netherlands
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37
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van Wijk R, van Solinge WW, Nerlov C, Beutler E, Gelbart T, Rijksen G, Nielsen FC. Disruption of a novel regulatory element in the erythroid-specific promoter of the human PKLR gene causes severe pyruvate kinase deficiency. Blood 2003; 101:1596-602. [PMID: 12393511 DOI: 10.1182/blood-2002-07-2321] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We established the molecular basis for pyruvate kinase (PK) deficiency in a white male patient with severe nonspherocytic hemolytic anemia. The paternal allele exhibited the common PKLR cDNA sequence (c.) 1529G>A mutation, known to be associated with PK deficiency. On the maternal allele, 3 in cis mutations were identified in the erythroid-specific promoter region of the gene: one deletion of thymine -248 and 2 single nucleotide substitutions, nucleotide (nt) -324T>A and nt -83G>C. Analysis of the patient's RNA demonstrated the presence of only the 1529A allele, indicating severely reduced transcription from the allele linked to the mutated promoter region. Transfection of promoter constructs into erythroleukemic K562 cells showed that the most upstream -324T>A and -248delT mutations were nonfunctional polymorphisms. In contrast, the -83G>C mutation strongly reduced promoter activity. Site-directed mutagenesis of the promoter region revealed the presence of a putative regulatory element (PKR-RE1) whose core binding motif, CTCTG, is located between nt -87 and nt -83. Electrophoretic mobility shift assay using K562 nuclear extracts indicated binding of an as-yet-unidentified trans-acting factor. This novel element mediates the effects of factors necessary for regulation of pyruvate kinase gene expression during red cell differentiation and maturation.
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Affiliation(s)
- Richard van Wijk
- Department of Clinical Chemistry, University Medical Center Utrecht, The Netherlands
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38
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Manco L, Bento C, Ribeiro ML, Tamagnini G. Consequences at mrna level of the pklr gene splicing mutations IVS10(+1)G→C and IVS8(+2)T→G causing pyruvate kinase deficiency. Br J Haematol 2002. [DOI: 10.1046/j.0007-1048.2002.03665.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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39
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Manco L, Bento C, Ribeiro ML, Tamagnini G. Consequences at mRNA level of the PKLR gene splicing mutations IVS10(+1)GC and IVS8(+2)TG causing pyruvate kinase deficiency. Br J Haematol 2002. [DOI: 10.1046/j.1365-2141.2002.03631_9.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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40
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Salvatori R, Fan X, Mullis PE, Haile A, Levine MA. Decreased expression of the GHRH receptor gene due to a mutation in a Pit-1 binding site. Mol Endocrinol 2002; 16:450-8. [PMID: 11875102 DOI: 10.1210/mend.16.3.0785] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A variety of mutations in the gene encoding the GHRH receptor (GHRHR) that are predicted to alter protein structure or function have been recently described in patients with isolated GH deficiency type IB. In the present report we describe a patient with isolated GH deficiency type IB who was heterozygous for two novel mutations in this gene: a missense mutation in codon 329 that replaces lysine with glutamic acid (K329E) and an A-->C transversion (position -124) in one of the two sites of the promoter region that binds the pituitary-specific transcription factor Pit-1, which is required for GHRHR expression. Chinese hamster ovary cells that were transfected with a cDNA encoding the K329E GHRHR expressed the receptor but failed to show a cAMP response after treatment with GHRH, confirming the lack of functionality. To test the effect of the A-->C mutation at position -124 of the promoter, we transfected rat GH3 pituitary cells, which express endogenous Pit-1, with plasmids in which the luciferase reporter gene was under the control of either the wild-type or the mutant promoter. GH3 cells expressing the mutant promoter showed significantly less luciferase activity than cells expressing the wild-type promoter. DNA-binding studies confirmed that the A-->C base change markedly reduces DNA binding to the Pit-1 protein. These results demonstrate that mutations in the GHRHR are not limited to the coding sequence and that promoter mutations that impair Pit-1 binding can reduce expression of the GHRHR gene.
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Affiliation(s)
- Roberto Salvatori
- Division of Endocrinology, and the Ilyssa Center for Molecular and Cellular Endocrinology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
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41
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Manco L, Abade A. Pyruvate kinase deficiency: prevalence of the 1456C-->T mutation in the Portuguese population. Clin Genet 2001; 60:472-3. [PMID: 11846742 DOI: 10.1034/j.1399-0004.2001.600612.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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42
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Lee PL, Halloran C, Beutler E. Polymorphisms in the transferrin 5' flanking region associated with differences in total iron binding capacity: possible implications in iron homeostasis. Blood Cells Mol Dis 2001; 27:539-48. [PMID: 11500065 DOI: 10.1006/bcmd.2001.0418] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have identified five single nucleotide polymorphisms (SNPs) upstream (5') of the transferrin coding region. One polymorphism is in the 5' UTR at nt +49, and four are in the promoter region at nt -34, -551, -617, and -739, numbering from the start of transcription. The -34 and -617 SNPs are tightly but not completely linked. The -34 polymorphism lies between a conserved Sp1 site and the TATA box. The -617 polymorphism is within the DRII enhancer region. Five haplotypes have been defined from these SNPs by the identification of at least one homozygous individual, and two other haplotypes were deduced from heterozygous individuals. The total iron-binding capacity associated with each transferrin haplotype was haplotype 2 > 1 > 4 > 3. Transferrin promoter haplotype 2 had a significantly higher mean TIBC and haplotype 3 had a significantly lower mean TIBC than the more common haplotype 1. Persons with haplotype 4, which includes the -34T and -617A minor alleles, have a lower mean TIBC but the difference was not statistically significant. In normal individuals, the differences in the haplotypes were not found to be associated with differences in transferrin saturation and ferritin levels. There was no difference in the extent of increase in the mean TIBC levels in individuals with iron deficiency anemia in regard to their haplotype. Furthermore, there was no difference in the relative frequencies of the transferrin haplotypes in the iron-deficient population. In hemochromatosis patients who were homozygous for the C282Y HFE mutation, no particular haplotype was associated with a significant difference in transferrin saturation or ferritin levels. In White patients with Parkinson's disease, a disorder in which there is abnormal iron deposition in the brain, the presence of transferrin haplotype 3 was in slight excess over the normal White population.
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Affiliation(s)
- P L Lee
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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