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Liu Y, Flamier A, Bell GW, Diao AJ, Whitfield TW, Wang HC, Wu Y, Schulte F, Friesen M, Guo R, Mitalipova M, Liu XS, Vos SM, Young RA, Jaenisch R. MECP2 directly interacts with RNA polymerase II to modulate transcription in human neurons. Neuron 2024:S0896-6273(24)00245-9. [PMID: 38697112 DOI: 10.1016/j.neuron.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/08/2024] [Accepted: 04/05/2024] [Indexed: 05/04/2024]
Abstract
Mutations in the methyl-DNA-binding protein MECP2 cause the neurodevelopmental disorder Rett syndrome (RTT). How MECP2 contributes to transcriptional regulation in normal and disease states is unresolved; it has been reported to be an activator and a repressor. We describe here the first integrated CUT&Tag, transcriptome, and proteome analyses using human neurons with wild-type (WT) and mutant MECP2 molecules. MECP2 occupies CpG-rich promoter-proximal regions in over four thousand genes in human neurons, including a plethora of autism risk genes, together with RNA polymerase II (RNA Pol II). MECP2 directly interacts with RNA Pol II, and genes occupied by both proteins showed reduced expression in neurons with MECP2 patient mutations. We conclude that MECP2 acts as a positive cofactor for RNA Pol II gene expression at many neuronal genes that harbor CpG islands in promoter-proximal regions and that RTT is due, in part, to the loss of gene activity of these genes in neurons.
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Affiliation(s)
- Yi Liu
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Anthony Flamier
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - George W Bell
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Annette Jun Diao
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Troy W Whitfield
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Hao-Che Wang
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Yizhe Wu
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Fabian Schulte
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Max Friesen
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Ruisi Guo
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Maisam Mitalipova
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - X Shawn Liu
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY 10032, USA
| | - Seychelle M Vos
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Richard A Young
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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2
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Liu L, Nguyen H, Das U, Ogunsola S, Yu J, Lei L, Kung M, Pejhan S, Rastegar M, Xie J. Epigenetic control of adaptive or homeostatic splicing during interval-training activities. Nucleic Acids Res 2024:gkae311. [PMID: 38661216 DOI: 10.1093/nar/gkae311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/03/2024] [Accepted: 04/14/2024] [Indexed: 04/26/2024] Open
Abstract
Interval-training activities induce adaptive cellular changes without altering their fundamental identity, but the precise underlying molecular mechanisms are not fully understood. In this study, we demonstrate that interval-training depolarization (ITD) of pituitary cells triggers distinct adaptive or homeostatic splicing responses of alternative exons. This occurs while preserving the steady-state expression of the Prolactin and other hormone genes. The nature of these splicing responses depends on the exon's DNA methylation status, the methyl-C-binding protein MeCP2 and its associated CA-rich motif-binding hnRNP L. Interestingly, the steady expression of the Prolactin gene is also reliant on MeCP2, whose disruption leads to exacerbated multi-exon aberrant splicing and overexpression of the hormone gene transcripts upon ITD, similar to the observed hyperprolactinemia or activity-dependent aberrant splicing in Rett Syndrome. Therefore, epigenetic control is crucial for both adaptive and homeostatic splicing and particularly the steady expression of the Prolactin hormone gene during ITD. Disruption in this regulation may have significant implications for the development of progressive diseases.
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Affiliation(s)
- Ling Liu
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Hai Nguyen
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Urmi Das
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Samuel Ogunsola
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Jiankun Yu
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Lei Lei
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Matthew Kung
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Shervin Pejhan
- Biochemistry & Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Mojgan Rastegar
- Biochemistry & Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Jiuyong Xie
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
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3
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Wang Q, Luo S, Xiong D, Xu X, Zhao X, Duan L. Quantitative investigation of the effects of DNA modifications and protein mutations on MeCP2-MBD-DNA interactions. Int J Biol Macromol 2023; 247:125690. [PMID: 37423448 DOI: 10.1016/j.ijbiomac.2023.125690] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/27/2023] [Accepted: 07/02/2023] [Indexed: 07/11/2023]
Abstract
DNA methylation as an important epigenetic marker, has gained attention for the significance of three oxidative modifications (hydroxymethyl-C (hmC), formyl-C (fC), and carboxyl-C (caC)). Mutations occurring in the methyl-CpG-binding domain (MBD) of MeCP2 result in Rett. However, uncertainties persist regarding DNA modification and MBD mutation-induced interaction changes. Here, molecular dynamics simulations were used to investigate the underlying mechanisms behind changes due to different modifications of DNA and MBD mutations. Alanine scanning combined with the interaction entropy method was employed to accurately evaluate the binding free energy. The results show that MBD has the strongest binding ability for mCDNA, followed by caC, hmC, and fCDNA, with the weakest binding ability observed for CDNA. Further analysis revealed that mC modification induces DNA bending, causing residues R91 and R162 closer to the DNA. This proximity enhances van der Waals and electrostatic interactions. Conversely, the caC/hmC and fC modifications lead to two loop regions (near K112 and K130) closer to DNA, respectively. Furthermore, DNA modifications promote the formation of stable hydrogen bond networks, however mutations in the MBD significantly reduce the binding free energy. This study provides detailed insight into the effects of DNA modifications and MBD mutations on binding ability. It emphasizes the necessity for research and development of targeted Rett compounds that induce conformational compatibility between MBD and DNA, enhancing the stability and strength of their interactions.
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Affiliation(s)
- Qihang Wang
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Song Luo
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Danyang Xiong
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Xiaole Xu
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Xiaoyu Zhao
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Lili Duan
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China.
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Kaplun DS, Kaluzhny DN, Prokhortchouk EB, Zhenilo SV. DNA Methylation: Genomewide Distribution, Regulatory Mechanism and Therapy Target. Acta Naturae 2022; 14:4-19. [PMID: 36694897 PMCID: PMC9844086 DOI: 10.32607/actanaturae.11822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/29/2022] [Indexed: 01/22/2023] Open
Abstract
DNA methylation is the most important epigenetic modification involved in the regulation of transcription, imprinting, establishment of X-inactivation, and the formation of a chromatin structure. DNA methylation in the genome is often associated with transcriptional repression and the formation of closed heterochromatin. However, the results of genome-wide studies of the DNA methylation pattern and transcriptional activity of genes have nudged us toward reconsidering this paradigm, since the promoters of many genes remain active despite their methylation. The differences in the DNA methylation distribution in normal and pathological conditions allow us to consider methylation as a diagnostic marker or a therapy target. In this regard, the need to investigate the factors affecting DNA methylation and those involved in its interpretation becomes pressing. Recently, a large number of protein factors have been uncovered, whose ability to bind to DNA depends on their methylation. Many of these proteins act not only as transcriptional activators or repressors, but also affect the level of DNA methylation. These factors are considered potential therapeutic targets for the treatment of diseases resulting from either a change in DNA methylation or a change in the interpretation of its methylation level. In addition to protein factors, a secondary DNA structure can also affect its methylation and can be considered as a therapy target. In this review, the latest research into the DNA methylation landscape in the genome has been summarized to discuss why some DNA regions avoid methylation and what factors can affect its level or interpretation and, therefore, can be considered a therapy target.
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Affiliation(s)
- D. S. Kaplun
- Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071 Russia
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119071 Russia
| | - D. N. Kaluzhny
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia
| | - E. B. Prokhortchouk
- Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071 Russia
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119071 Russia
| | - S. V. Zhenilo
- Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071 Russia
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119071 Russia
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5
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Chang KJ, Wu HY, Yarmishyn AA, Li CY, Hsiao YJ, Chi YC, Lo TC, Dai HJ, Yang YC, Liu DH, Hwang DK, Chen SJ, Hsu CC, Kao CL. Genetics behind Cerebral Disease with Ocular Comorbidity: Finding Parallels between the Brain and Eye Molecular Pathology. Int J Mol Sci 2022; 23:ijms23179707. [PMID: 36077104 PMCID: PMC9456058 DOI: 10.3390/ijms23179707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/18/2022] [Accepted: 08/22/2022] [Indexed: 11/30/2022] Open
Abstract
Cerebral visual impairments (CVIs) is an umbrella term that categorizes miscellaneous visual defects with parallel genetic brain disorders. While the manifestations of CVIs are diverse and ambiguous, molecular diagnostics stand out as a powerful approach for understanding pathomechanisms in CVIs. Nevertheless, the characterization of CVI disease cohorts has been fragmented and lacks integration. By revisiting the genome-wide and phenome-wide association studies (GWAS and PheWAS), we clustered a handful of renowned CVIs into five ontology groups, namely ciliopathies (Joubert syndrome, Bardet–Biedl syndrome, Alstrom syndrome), demyelination diseases (multiple sclerosis, Alexander disease, Pelizaeus–Merzbacher disease), transcriptional deregulation diseases (Mowat–Wilson disease, Pitt–Hopkins disease, Rett syndrome, Cockayne syndrome, X-linked alpha-thalassaemia mental retardation), compromised peroxisome disorders (Zellweger spectrum disorder, Refsum disease), and channelopathies (neuromyelitis optica spectrum disorder), and reviewed several mutation hotspots currently found to be associated with the CVIs. Moreover, we discussed the common manifestations in the brain and the eye, and collated animal study findings to discuss plausible gene editing strategies for future CVI correction.
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Affiliation(s)
- Kao-Jung Chang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
| | - Hsin-Yu Wu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | | | - Cheng-Yi Li
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yu-Jer Hsiao
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yi-Chun Chi
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Tzu-Chen Lo
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - He-Jhen Dai
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Yi-Chiang Yang
- Department of Physical Medicine and Rehabilitation, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Ding-Hao Liu
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Physical Medicine and Rehabilitation, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - De-Kuang Hwang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Shih-Jen Chen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Chih-Chien Hsu
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Correspondence: (C.-C.H.); (C.-L.K.); Tel.: +886-2-287-573-25 (C.-C.H.); +886-2-287-573-63 (C.-L.K.)
| | - Chung-Lan Kao
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Department of Physical Medicine and Rehabilitation, Taipei Veterans General Hospital, Taipei 11217, Taiwan
- Department of Physical Medicine and Rehabilitation, School of Medicine, National Yang Ming Chiao Tung University, Taipei 112304, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-Devices (IDS2B), National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
- Correspondence: (C.-C.H.); (C.-L.K.); Tel.: +886-2-287-573-25 (C.-C.H.); +886-2-287-573-63 (C.-L.K.)
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6
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Chávez-García C, Hénin J, Karttunen M. Multiscale Computational Study of the Conformation of the Full-Length Intrinsically Disordered Protein MeCP2. J Chem Inf Model 2022; 62:958-970. [PMID: 35130441 DOI: 10.1021/acs.jcim.1c01354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The malfunction of the methyl-CpG binding protein 2 (MeCP2) is associated with the Rett syndrome, one of the most common causes of cognitive impairment in females. MeCP2 is an intrinsically disordered protein (IDP), making its experimental characterization a challenge. There is currently no structure available for the full-length MeCP2 in any of the databases, and only the structure of its MBD domain has been solved. We used this structure to build a full-length model of MeCP2 by completing the rest of the protein via ab initio modeling. Using a combination of all-atom and coarse-grained simulations, we characterized its structure and dynamics as well as the conformational space sampled by the ID and transcriptional repression domain (TRD) domains in the absence of the rest of the protein. The present work is the first computational study of the full-length protein. Two main conformations were sampled in the coarse-grained simulations: a globular structure similar to the one observed in the all-atom force field and a two-globule conformation. Our all-atom model is in good agreement with the available experimental data, predicting amino acid W104 to be buried, amino acids R111 and R133 to be solvent-accessible, and having a 4.1% α-helix content, compared to the 4% found experimentally. Finally, we compared the model predicted by AlphaFold to our Modeller model. The model was not stable in water and underwent further folding. Together, these simulations provide a detailed (if perhaps incomplete) conformational ensemble of the full-length MeCP2, which is compatible with experimental data and can be the basis of further studies, e.g., on mutants of the protein or its interactions with its biological partners.
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Affiliation(s)
- Cecilia Chávez-García
- Department of Chemistry, the University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada.,The Centre of Advanced Materials and Biomaterials Research, the University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Jérôme Hénin
- Laboratoire de Biochimie Théorique UPR 9080, CNRS and Université de Paris, Paris 75005, France
| | - Mikko Karttunen
- Department of Chemistry, the University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada.,The Centre of Advanced Materials and Biomaterials Research, the University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada.,Department of Physics and Astronomy, the University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7, Canada
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7
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Collins BE, Neul JL. Rett Syndrome and MECP2 Duplication Syndrome: Disorders of MeCP2 Dosage. Neuropsychiatr Dis Treat 2022; 18:2813-2835. [PMID: 36471747 PMCID: PMC9719276 DOI: 10.2147/ndt.s371483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/14/2022] [Indexed: 11/30/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused predominantly by loss-of-function mutations in the gene Methyl-CpG-binding protein 2 (MECP2), which encodes the MeCP2 protein. RTT is a MECP2-related disorder, along with MECP2 duplication syndrome (MDS), caused by gain-of-function duplications of MECP2. Nearly two decades of research have advanced our knowledge of MeCP2 function in health and disease. The following review will discuss MeCP2 protein function and its dysregulation in the MECP2-related disorders RTT and MDS. This will include a discussion of the genetic underpinnings of these disorders, specifically how sporadic X-chromosome mutations arise and manifest in specific populations. We will then review current diagnostic guidelines and clinical manifestations of RTT and MDS. Next, we will delve into MeCP2 biology, describing the dual landscapes of methylated DNA and its reader MeCP2 across the neuronal genome as well as the function of MeCP2 as a transcriptional modulator. Following this, we will outline common MECP2 mutations and genotype-phenotype correlations in both diseases, with particular focus on mutations associated with relatively mild disease in RTT. We will also summarize decades of disease modeling and resulting molecular, synaptic, and behavioral phenotypes associated with RTT and MDS. Finally, we list several therapeutics in the development pipeline for RTT and MDS and available evidence of their safety and efficacy.
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Affiliation(s)
- Bridget E Collins
- Medical Scientist Training Program, Vanderbilt University, Nashville, TN, USA
| | - Jeffrey L Neul
- Vanderbilt Kennedy Center, Departments of Pediatrics, Pharmacology, and Special Education, Vanderbilt University Medical Center and Vanderbilt University, Nashville, TN, USA
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8
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Stabilization Effect of Intrinsically Disordered Regions on Multidomain Proteins: The Case of the Methyl-CpG Protein 2, MeCP2. Biomolecules 2021; 11:biom11081216. [PMID: 34439881 PMCID: PMC8391517 DOI: 10.3390/biom11081216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/04/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022] Open
Abstract
Intrinsic disorder plays an important functional role in proteins. Disordered regions are linked to posttranslational modifications, conformational switching, extra/intracellular trafficking, and allosteric control, among other phenomena. Disorder provides proteins with enhanced plasticity, resulting in a dynamic protein conformational/functional landscape, with well-structured and disordered regions displaying reciprocal, interdependent features. Although lacking well-defined conformation, disordered regions may affect the intrinsic stability and functional properties of ordered regions. MeCP2, methyl-CpG binding protein 2, is a multifunctional transcriptional regulator associated with neuronal development and maturation. MeCP2 multidomain structure makes it a prototype for multidomain, multifunctional, intrinsically disordered proteins (IDP). The methyl-binding domain (MBD) is one of the key domains in MeCP2, responsible for DNA recognition. It has been reported previously that the two disordered domains flanking MBD, the N-terminal domain (NTD) and the intervening domain (ID), increase the intrinsic stability of MBD against thermal denaturation. In order to prove unequivocally this stabilization effect, ruling out any artifactual result from monitoring the unfolding MBD with a local fluorescence probe (the single tryptophan in MBD) or from driving the protein unfolding by temperature, we have studied the MBD stability by differential scanning calorimetry (reporting on the global unfolding process) and chemical denaturation (altering intramolecular interactions by a different mechanism compared to thermal denaturation).
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9
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Vermudez SAD, Gogliotti RG, Arthur B, Buch A, Morales C, Moxley Y, Rajpal H, Conn PJ, Niswender CM. Profiling beneficial and potential adverse effects of MeCP2 overexpression in a hypomorphic Rett syndrome mouse model. GENES, BRAIN, AND BEHAVIOR 2021; 21:e12752. [PMID: 34002468 PMCID: PMC8599502 DOI: 10.1111/gbb.12752] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/15/2021] [Accepted: 05/16/2021] [Indexed: 01/03/2023]
Abstract
De novo loss-of-function mutations in methyl-CpG-binding protein 2 (MeCP2) lead to the neurodevelopmental disorder Rett syndrome (RTT). Despite promising results from strategies aimed at increasing MeCP2 levels, additional studies exploring how hypomorphic MeCP2 mutations impact the therapeutic window are needed. Here, we investigated the consequences of genetically introducing a wild-type MECP2 transgene in the Mecp2 R133C mouse model of RTT. The MECP2 transgene reversed the majority of RTT-like phenotypes exhibited by male and female Mecp2 R133C mice. However, three core symptom domains were adversely affected in female Mecp2R133C/+ animals; these phenotypes resemble those observed in disease contexts of excess MeCP2. Parallel control experiments in Mecp2Null/+ mice linked these adverse effects to the hypomorphic R133C mutation. Collectively, these data provide evidence regarding the safety and efficacy of genetically overexpressing functional MeCP2 in Mecp2 R133C mice and suggest that personalized approaches may warrant consideration for the clinical assessment of MeCP2-targeted therapies.
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Affiliation(s)
- Sheryl Anne D. Vermudez
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA
| | - Rocco G. Gogliotti
- Department of Molecular Pharmacology and NeuroscienceLoyola University ChicagoChicagoIllinoisUSA
| | - Bright Arthur
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA
| | - Aditi Buch
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA
| | - Clarissa Morales
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA
| | - Yuta Moxley
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA
| | - Hemangi Rajpal
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA
| | - P. Jeffrey Conn
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA,Vanderbilt Kennedy CenterVanderbilt UniversityNashvilleTennesseeUSA,Vanderbilt Institute of Chemical BiologyVanderbilt UniversityNashvilleTennesseeUSA
| | - Colleen M. Niswender
- Department of Pharmacology and Warren Center for Neuroscience Drug DiscoveryVanderbilt UniversityNashvilleTennesseeUSA,Vanderbilt Kennedy CenterVanderbilt UniversityNashvilleTennesseeUSA,Vanderbilt Institute of Chemical BiologyVanderbilt UniversityNashvilleTennesseeUSA
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10
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Ortega-Alarcon D, Claveria-Gimeno R, Vega S, Jorge-Torres OC, Esteller M, Abian O, Velazquez-Campoy A. Influence of the disordered domain structure of MeCP2 on its structural stability and dsDNA interaction. Int J Biol Macromol 2021; 175:58-66. [PMID: 33548325 DOI: 10.1016/j.ijbiomac.2021.01.206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/17/2021] [Accepted: 01/29/2021] [Indexed: 10/22/2022]
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a transcriptional regulator and a chromatin-associated structural protein. MeCP2 deregulation results in two neurodevelopmental disorders: MeCP2 dysfunction is associated with Rett syndrome, while excess of activity is associated with MeCP2 duplication syndrome. MeCP2 is an intrinsically disordered protein (IDP) constituted by six structural domains with variable, small percentage of well-defined secondary structure. Two domains, methyl-CpG binding domain (MBD) and transcription repressor domain (TRD), are the elements responsible for dsDNA binding ability and recruitment of the gene transcription/silencing machinery, respectively. Previously we studied the influence of the completely disordered, MBD-flanking domains (N-terminal domain, NTD, and intervening domain, ID) on the structural and functional features of the MBD (Claveria-Gimeno, R. et al. Sci Rep. 2017, 7, 41,635). Here we report the biophysical study of the influence of the remaining domains (transcriptional repressor domain, TRD, and C-terminal domains, CTDα and CTDβ) on the structural stability of MBD and the dsDNA binding capabilities of MBD and ID. The influence of distant disordered domains on MBD properties makes it necessary to consider the NTD-MBD-ID variant as the minimal protein construct for studying dsDNA/chromatin binding properties, while the full-length protein should be considered for transcriptional regulation studies.
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Affiliation(s)
- David Ortega-Alarcon
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza 50018, Spain
| | - Rafael Claveria-Gimeno
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza 50018, Spain; Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
| | - Sonia Vega
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza 50018, Spain
| | - Olga C Jorge-Torres
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Badalona, Barcelona, Spain
| | - Manel Esteller
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Badalona, Barcelona, Spain; Centro de Investigacion Biomedica en Red Cancer (CIBERONC), 28029 Madrid, Spain; Institucio Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain; Physiological Sciences Department, School of Medicine and Health Sciences, University of Barcelona (UB), 08907, l'Hospitalet de Llobregat, Barcelona, Spain
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza 50018, Spain; Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza 50018, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain; Fundación ARAID, Gobierno de Aragón, 50018 Zaragoza, Spain.
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11
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Good KV, Vincent JB, Ausió J. MeCP2: The Genetic Driver of Rett Syndrome Epigenetics. Front Genet 2021; 12:620859. [PMID: 33552148 PMCID: PMC7859524 DOI: 10.3389/fgene.2021.620859] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/05/2021] [Indexed: 12/24/2022] Open
Abstract
Mutations in methyl CpG binding protein 2 (MeCP2) are the major cause of Rett syndrome (RTT), a rare neurodevelopmental disorder with a notable period of developmental regression following apparently normal initial development. Such MeCP2 alterations often result in changes to DNA binding and chromatin clustering ability, and in the stability of this protein. Among other functions, MeCP2 binds to methylated genomic DNA, which represents an important epigenetic mark with broad physiological implications, including neuronal development. In this review, we will summarize the genetic foundations behind RTT, and the variable degrees of protein stability exhibited by MeCP2 and its mutated versions. Also, past and emerging relationships that MeCP2 has with mRNA splicing, miRNA processing, and other non-coding RNAs (ncRNA) will be explored, and we suggest that these molecules could be missing links in understanding the epigenetic consequences incurred from genetic ablation of this important chromatin modifier. Importantly, although MeCP2 is highly expressed in the brain, where it has been most extensively studied, the role of this protein and its alterations in other tissues cannot be ignored and will also be discussed. Finally, the additional complexity to RTT pathology introduced by structural and functional implications of the two MeCP2 isoforms (MeCP2-E1 and MeCP2-E2) will be described. Epigenetic therapeutics are gaining clinical popularity, yet treatment for Rett syndrome is more complicated than would be anticipated for a purely epigenetic disorder, which should be taken into account in future clinical contexts.
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Affiliation(s)
- Katrina V. Good
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - John B. Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Centre for Addiction and Mental Health, Campbell Family Mental Health Research Institute, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
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12
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Ehrhart F, Jacobsen A, Rigau M, Bosio M, Kaliyaperumal R, Laros JFJ, Willighagen EL, Valencia A, Roos M, Capella-Gutierrez S, Curfs LMG, Evelo CT. A catalogue of 863 Rett-syndrome-causing MECP2 mutations and lessons learned from data integration. Sci Data 2021; 8:10. [PMID: 33452270 PMCID: PMC7810705 DOI: 10.1038/s41597-020-00794-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 11/30/2020] [Indexed: 11/09/2022] Open
Abstract
Rett syndrome (RTT) is a rare neurological disorder mostly caused by a genetic variation in MECP2. Making new MECP2 variants and the related phenotypes available provides data for better understanding of disease mechanisms and faster identification of variants for diagnosis. This is, however, currently hampered by the lack of interoperability between genotype-phenotype databases. Here, we demonstrate on the example of MECP2 in RTT that by making the genotype-phenotype data more Findable, Accessible, Interoperable, and Reusable (FAIR), we can facilitate prioritization and analysis of variants. In total, 10,968 MECP2 variants were successfully integrated. Among these variants 863 unique confirmed RTT causing and 209 unique confirmed benign variants were found. This dataset was used for comparison of pathogenicity predicting tools, protein consequences, and identification of ambiguous variants. Prediction tools generally recognised the RTT causing and benign variants, however, there was a broad range of overlap Nineteen variants were identified that were annotated as both disease-causing and benign, suggesting that there are additional factors in these cases contributing to disease development. Measurement(s) | Rett syndrome • phenotype • MECP2 Gene | Technology Type(s) | digital curation • network analysis | Sample Characteristic - Organism | Homo sapiens |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.13359476
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Affiliation(s)
- Friederike Ehrhart
- Department of Bioinformatics - BiGCaT, NUTRIM School of Nutrition and Translational Research in Metabolism, MHeNS School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands. .,GKC - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Annika Jacobsen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Maria Rigau
- Barcelona Supercomputing Centre (BSC), Barcelona, Spain
| | - Mattia Bosio
- Barcelona Supercomputing Centre (BSC), Barcelona, Spain
| | - Rajaram Kaliyaperumal
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jeroen F J Laros
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Egon L Willighagen
- Department of Bioinformatics - BiGCaT, NUTRIM School of Nutrition and Translational Research in Metabolism, MHeNS School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Alfonso Valencia
- Barcelona Supercomputing Centre (BSC), Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Marco Roos
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Leopold M G Curfs
- GKC - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Chris T Evelo
- Department of Bioinformatics - BiGCaT, NUTRIM School of Nutrition and Translational Research in Metabolism, MHeNS School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.,GKC - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
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13
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Ortega-Alarcon D, Claveria-Gimeno R, Vega S, Jorge-Torres OC, Esteller M, Abian O, Velazquez-Campoy A. Molecular Context-Dependent Effects Induced by Rett Syndrome-Associated Mutations in MeCP2. Biomolecules 2020; 10:biom10111533. [PMID: 33182787 PMCID: PMC7696773 DOI: 10.3390/biom10111533] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/06/2020] [Accepted: 11/08/2020] [Indexed: 01/21/2023] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) is a transcriptional regulator and a chromatin-binding protein involved in neuronal development and maturation. Loss-of-function mutations in MeCP2 result in Rett syndrome (RTT), a neurodevelopmental disorder that is the main cause of mental retardation in females. MeCP2 is an intrinsically disordered protein (IDP) constituted by six domains. Two domains are the main responsible elements for DNA binding (methyl-CpG binding domain, MBD) and recruitment of gene transcription/silencing machinery (transcription repressor domain, TRD). These two domains concentrate most of the RTT-associated mutations. R106W and R133C are associated with severe and mild RTT phenotype, respectively. We have performed a comprehensive characterization of the structural and functional impact of these substitutions at molecular level. Because we have previously shown that the MBD-flanking disordered domains (N-terminal domain, NTD, and intervening domain, ID) exert a considerable influence on the structural and functional features of the MBD (Claveria-Gimeno, R. et al. Sci Rep. 2017, 7, 41635), here we report the biophysical study of the influence of the protein scaffold on the structural and functional effect induced by these two RTT-associated mutations. These results represent an example of how a given mutation may show different effects (sometimes opposing effects) depending on the molecular context.
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Affiliation(s)
- David Ortega-Alarcon
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (D.O.-A.); (R.C.-G.); (S.V.)
| | - Rafael Claveria-Gimeno
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (D.O.-A.); (R.C.-G.); (S.V.)
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
| | - Sonia Vega
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (D.O.-A.); (R.C.-G.); (S.V.)
| | - Olga C. Jorge-Torres
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Badalona, Spain; (O.C.J.-T.); (M.E.)
| | - Manel Esteller
- Josep Carreras Leukaemia Research Institute (IJC), 08916 Badalona, Spain; (O.C.J.-T.); (M.E.)
- Centro de Investigacion Biomedica en Red Cancer (CIBERONC), 28029 Madrid, Spain
- Institucio Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
- Physiological Sciences Department, School of Medicine and Health Sciences, University of Barcelona (UB), l’Hospitalet de Llobregat, 08907 Barcelona, Spain
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (D.O.-A.); (R.C.-G.); (S.V.)
- Instituto Aragonés de Ciencias de la Salud (IACS), 50009 Zaragoza, Spain
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Correspondence: (O.A.); (A.V.-C.); Tel.: +34-876-555-417 (O.A.); +34-976-762-996 (A.V.-C.)
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; (D.O.-A.); (R.C.-G.); (S.V.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Fundación ARAID, Gobierno de Aragón, 50009 Zaragoza, Spain
- Correspondence: (O.A.); (A.V.-C.); Tel.: +34-876-555-417 (O.A.); +34-976-762-996 (A.V.-C.)
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14
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Kucukkal TG, Amin RU. Computational and structural studies of MeCP2 and associated mutants. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2020. [DOI: 10.1142/s0219633620410011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Rett Syndrome is a rare genetic disorder exclusively seen in girls. Approximately 95% of RTT cases is caused by mutations in the MeCP2 gene which codes for Methyl-CpG-binding protein 2 (MeCP2). In this review, first, a brief introductory review of Rett Syndrome, MeCP2 protein structure and function, mutation types and frequencies, and phenotype–genotype relationships were provided. After that, the current knowledge on the wild-type and mutant MeCP2 protein structure and dynamics as well as its binding to DNA is reviewed. The review particularly focuses on computational (such as molecular dynamics) and experimental (such as electrophoretic mobility shift assays) studies on the MeCP2 binding to different types of DNA as well as the computational and experimental (such as circular dichroism) studies on the stability changes upon mutations. In the end, a brief opinion on future outlook for further computational studies is provided.
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Affiliation(s)
- Tugba G. Kucukkal
- Department of Science, Technology and Mathematics, Gallaudet University, 800 Florida Ave NE, Washington, DC 20002, USA
- Quest Student Research Institute, 14153 Robert Paris Ct Chantilly, VA 20151, USA
| | - Rijul U. Amin
- Quest Student Research Institute, 14153 Robert Paris Ct Chantilly, VA 20151, USA
- Department of Biological Sciences, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, PA 15260, USA
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15
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Tillotson R, Bird A. The Molecular Basis of MeCP2 Function in the Brain. J Mol Biol 2020; 432:1602-1623. [PMID: 31629770 DOI: 10.1016/j.jmb.2019.10.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/04/2019] [Accepted: 10/05/2019] [Indexed: 12/14/2022]
Abstract
MeCP2 is a reader of the DNA methylome that occupies a large proportion of the genome due to its high abundance and the frequency of its target sites. It has been the subject of extensive study because of its link with 'MECP2-related disorders', of which Rett syndrome is the most prevalent. This review integrates evidence from patient mutation data with results of experimental studies using mouse models, cell lines and in vitro systems to critically evaluate our understanding of MeCP2 protein function. Recent evidence challenges the idea that MeCP2 is a multifunctional hub that integrates diverse processes to underpin neuronal function, suggesting instead that its primary role is to recruit the NCoR1/2 co-repressor complex to methylated sites in the genome, leading to dampening of gene expression.
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Affiliation(s)
- Rebekah Tillotson
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada; Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DS, UK
| | - Adrian Bird
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh, EH9 3BF, UK.
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16
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Rett syndrome-causing mutations compromise MeCP2-mediated liquid-liquid phase separation of chromatin. Cell Res 2020; 30:393-407. [PMID: 32111972 DOI: 10.1038/s41422-020-0288-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/05/2020] [Indexed: 01/09/2023] Open
Abstract
Rett syndrome (RTT), a severe postnatal neurodevelopmental disorder, is caused by mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MeCP2). MeCP2 is a chromatin organizer regulating gene expression. RTT-causing mutations have been shown to affect this function. However, the mechanism by which MeCP2 organizes chromatin is unclear. In this study, we found that MeCP2 can induce compaction and liquid-liquid phase separation of nucleosomal arrays in vitro, and DNA methylation further enhances formation of chromatin condensates by MeCP2. Interestingly, RTT-causing mutations compromise MeCP2-mediated chromatin phase separation, while benign variants have little effect on this process. Moreover, MeCP2 competes with linker histone H1 to form mutually exclusive chromatin condensates in vitro and distinct heterochromatin foci in vivo. RTT-causing mutations reduce or even abolish the ability of MeCP2 to compete with histone H1 and to form chromatin condensates. Together, our results identify a novel mechanism by which phase separation underlies MeCP2-mediated heterochromatin formation and reveal the potential link between this process and the pathology of RTT.
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17
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Yang H, Li K, Han S, Zhou A, Zhou ZJ. Leveraging the genetic basis of Rett syndrome to ascertain pathophysiology. Neurobiol Learn Mem 2019; 165:106961. [PMID: 30447288 PMCID: PMC6635128 DOI: 10.1016/j.nlm.2018.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 09/18/2018] [Accepted: 11/14/2018] [Indexed: 10/27/2022]
Abstract
Mutations in the methyl-CpG binding protein 2 (MECP2) gene cause Rett syndrome (RTT), a progressive X-linked neurological disorder characterized by loss of developmental milestones, intellectual disability and breathing abnormality. Despite being a monogenic disorder, the pathogenic mechanisms by which mutations in MeCP2 impair neuronal function and underlie the RTT symptoms have been challenging to elucidate. The seemingly simple genetic root and the availability of genetic data from RTT patients have led to the generation and characterization of a series of mouse models recapitulating RTT-associated genetic mutations. This review focuses on the studies of RTT mouse models and describe newly obtained pathogenic insights from these studies. We also highlight the potential of studying pathophysiology using genetics-based modeling approaches in rodents and suggest a future direction to tackle the pathophysiology of intellectual disability with known or complex genetic causes.
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Affiliation(s)
- Hua Yang
- Qingdao Jiaozhou Central Hospital, Jiaozhou City, Shandong Province 266300, China
| | - Kequan Li
- Qingdao Jiaozhou Central Hospital, Jiaozhou City, Shandong Province 266300, China
| | - Song Han
- Jiaozhou People's Hospital, Jiaozhou City, Shandong Province 266300, China
| | - Ailing Zhou
- Jiaozhou People's Hospital, Jiaozhou City, Shandong Province 266300, China
| | - Zhaolan Joe Zhou
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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18
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Genomic insights into MeCP2 function: A role for the maintenance of chromatin architecture. Curr Opin Neurobiol 2019; 59:174-179. [PMID: 31430649 DOI: 10.1016/j.conb.2019.07.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/07/2019] [Indexed: 01/05/2023]
Abstract
Methyl-CpG binding protein 2 (MeCP2) plays fundamental roles in the nervous system, as both gain-of-function and loss-of-function of MECP2 are associated with severe neurological conditions. Understanding the molecular function of MeCP2 will not only provide insights into the pathogenesis of MeCP2-related disorders, but will also shed light on the epigenetic regulation of neuronal function. In the past few years, a number of studies have provided mechanistic evidence that MeCP2 recruits co-repressor complexes to particular sequences of methylated DNA. Additionally, innovative design and high-throughput sequencing technologies have provided opportunities to study the effects of MeCP2 on the neuronal transcriptome at an unprecedented level of detail, demonstrating that MeCP2 modulates gene expression in a context-specific manner. These findings have raised new questions and challenged current models of MeCP2 function. In this review, we describe several recent developments, highlight future challenges, and articulate a model by which MeCP2 functions as an organizer of chromatin architecture to modulate global gene expression in the nervous system.
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19
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D'Annessa I, Gandaglia A, Brivio E, Stefanelli G, Frasca A, Landsberger N, Di Marino D. Tyr120Asp mutation alters domain flexibility and dynamics of MeCP2 DNA binding domain leading to impaired DNA interaction: Atomistic characterization of a Rett syndrome causing mutation. Biochim Biophys Acta Gen Subj 2018; 1862:1180-1189. [PMID: 29428602 DOI: 10.1016/j.bbagen.2018.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/30/2018] [Accepted: 02/06/2018] [Indexed: 11/28/2022]
Abstract
Mutations in the X-linked MECP2 gene represent the main origin of Rett syndrome, causing a profound intellectual disability in females. MeCP2 is an epigenetic transcriptional regulator containing two main functional domains: a methyl-CpG binding domain (MBD) and a transcription repression domain (TRD). Over 600 pathogenic mutations were reported to affect the whole protein; almost half of missense mutations affect the MBD. Understanding the impact of these mutations on the MBD structure and interaction with DNA will foster the comprehension of their pathogenicity and possibly genotype/phenotype correlation studies. Herein, we use molecular dynamics simulations to obtain a detailed view of the dynamics of WT and mutated MBD in the presence and absence of DNA. The pathogenic mutation Y120D is used as paradigm for our studies. Further, since the Y120 residue was previously found to be a phosphorylation site, we characterize the dynamic profile of the MBD also in the presence of Y120 phosphorylation (pY120). We found that addition of a phosphate group to Y120 or mutation in aspartic acid affect domain mobility that samples an alternative conformational space with respect to the WT, leading to impaired ability to interact with DNA. Experimental assays showing a significant reduction in the binding affinity between the mutated MBD and the DNA confirmed our predictions.
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Affiliation(s)
- Ilda D'Annessa
- Istituto di Chimica del Riconoscimento Molecolare, CNR, Milan, Italy
| | - Anna Gandaglia
- San Raffaele Rett Research Unit, San Raffaele Scientific Institute, Milan, Italy
| | - Elena Brivio
- San Raffaele Rett Research Unit, San Raffaele Scientific Institute, Milan, Italy
| | - Gilda Stefanelli
- San Raffaele Rett Research Unit, San Raffaele Scientific Institute, Milan, Italy
| | - Angelisa Frasca
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Nicoletta Landsberger
- San Raffaele Rett Research Unit, San Raffaele Scientific Institute, Milan, Italy; Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.
| | - Daniele Di Marino
- Department of Informatics, Institute of Computational Science, Università della Svizzera Italiana, Lugano, Switzerland.
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20
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Ginder GD, Williams DC. Readers of DNA methylation, the MBD family as potential therapeutic targets. Pharmacol Ther 2017; 184:98-111. [PMID: 29128342 DOI: 10.1016/j.pharmthera.2017.11.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
DNA methylation represents a fundamental epigenetic modification that regulates chromatin architecture and gene transcription. Many diseases, including cancer, show aberrant methylation patterns that contribute to the disease phenotype. DNA methylation inhibitors have been used to block methylation dependent gene silencing to treat hematopoietic neoplasms and to restore expression of developmentally silenced genes. However, these inhibitors disrupt methylation globally and show significant off-target toxicities. As an alternative approach, we have been studying readers of DNA methylation, the 5-methylcytosine binding domain family of proteins, as potential therapeutic targets to restore expression of aberrantly and developmentally methylated and silenced genes. In this review, we discuss the role of DNA methylation in gene regulation and cancer development, the structure and function of the 5-methylcytosine binding domain family of proteins, and the possibility of targeting the complexes these proteins form to treat human disease.
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Affiliation(s)
- Gordon D Ginder
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, United States; Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298, United States; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, United States.
| | - David C Williams
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
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21
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Johnson BS, Zhao YT, Fasolino M, Lamonica JM, Kim YJ, Georgakilas G, Wood KH, Bu D, Cui Y, Goffin D, Vahedi G, Kim TH, Zhou Z. Biotin tagging of MeCP2 in mice reveals contextual insights into the Rett syndrome transcriptome. Nat Med 2017; 23:1203-1214. [PMID: 28920956 PMCID: PMC5630512 DOI: 10.1038/nm.4406] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 08/18/2017] [Indexed: 12/12/2022]
Abstract
Mutations in MECP2 cause Rett syndrome (RTT), an X-linked neurological disorder characterized by regressive loss of neurodevelopmental milestones and acquired psychomotor deficits. However, the cellular heterogeneity of the brain impedes an understanding of how MECP2 mutations contribute to RTT. Here we developed a Cre-inducible method for cell type-specific biotin tagging of MeCP2 in mice. Combining this approach with an allelic series of knockin mice carrying frequent RTT mutations (T158M and R106W) enabled the selective profiling of RTT-associated nuclear transcriptomes in excitatory and inhibitory cortical neurons. We found that most gene expression changes are largely specific to each RTT mutation and cell type. Lowly expressed cell type-enriched genes are preferentially disrupted by MeCP2 mutations, with upregulated and downregulated genes reflecting distinct functional categories. Subcellular RNA analysis in MeCP2 mutant neurons further reveals reductions in the nascent transcription of long genes and uncovers widespread post-transcriptional compensation at the cellular level. Finally, we overcame X-linked cellular mosaicism in female RTT models and identified distinct gene expression changes between neighboring wild-type and mutant neurons, altogether providing contextual insights into RTT etiology that support personalized therapeutic interventions.
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Affiliation(s)
- Brian S Johnson
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Ying-Tao Zhao
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Maria Fasolino
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Janine M Lamonica
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Yoon Jung Kim
- Department of Biological Sciences and Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, USA
| | - George Georgakilas
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Kathleen H Wood
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Daniel Bu
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Yue Cui
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Darren Goffin
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Golnaz Vahedi
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Tae Hoon Kim
- Department of Biological Sciences and Center for Systems Biology, University of Texas at Dallas, Richardson, Texas, USA
| | - Zhaolan Zhou
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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22
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Gadalla KK, Vudhironarit T, Hector RD, Sinnett S, Bahey NG, Bailey ME, Gray SJ, Cobb SR. Development of a Novel AAV Gene Therapy Cassette with Improved Safety Features and Efficacy in a Mouse Model of Rett Syndrome. Mol Ther Methods Clin Dev 2017; 5:180-190. [PMID: 28497075 PMCID: PMC5423329 DOI: 10.1016/j.omtm.2017.04.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/19/2017] [Indexed: 12/21/2022]
Abstract
Rett syndrome (RTT), caused by loss-of-function mutations in the MECP2 gene, is a neurological disorder characterized by severe impairment of motor and cognitive functions. The aim of this study was to investigate the impact of vector design, dosage, and delivery route on the efficacy and safety of gene augmentation therapy in mouse models of RTT. Our results show that AAV-mediated delivery of MECP2 to Mecp2 null mice by systemic administration, and utilizing a minimal endogenous promoter, was associated with a narrow therapeutic window and resulted in liver toxicity at higher doses. Lower doses of this vector significantly extended the survival of mice lacking MeCP2 or expressing a mutant T158M allele but had no impact on RTT-like neurological phenotypes. Modifying vector design by incorporating an extended Mecp2 promoter and additional regulatory 3' UTR elements significantly reduced hepatic toxicity after systemic administration. Moreover, direct cerebroventricular injection of this vector into neonatal Mecp2-null mice resulted in high brain transduction efficiency, increased survival and body weight, and an amelioration of RTT-like phenotypes. Our results show that controlling levels of MeCP2 expression in the liver is achievable through modification of the expression cassette. However, it also highlights the importance of achieving high brain transduction to impact the RTT-like phenotypes.
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Affiliation(s)
- Kamal K.E. Gadalla
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
- Pharmacology Department, Faculty of Medicine, Tanta University, Tanta 31527, Egypt
| | - Thishnapha Vudhironarit
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Ralph D. Hector
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Sarah Sinnett
- Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Noha G. Bahey
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
- Histology Department, Faculty of Medicine, Tanta University, Tanta 31527, Egypt
| | - Mark E.S. Bailey
- School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Steven J. Gray
- Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Stuart R. Cobb
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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23
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Lamonica JM, Kwon DY, Goffin D, Fenik P, Johnson BS, Cui Y, Guo H, Veasey S, Zhou Z. Elevating expression of MeCP2 T158M rescues DNA binding and Rett syndrome-like phenotypes. J Clin Invest 2017; 127:1889-1904. [PMID: 28394263 DOI: 10.1172/jci90967] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/09/2017] [Indexed: 12/27/2022] Open
Abstract
Mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MeCP2) cause Rett syndrome (RTT), a neurological disorder affecting cognitive development, respiration, and motor function. Genetic restoration of MeCP2 expression reverses RTT-like phenotypes in mice, highlighting the need to search for therapeutic approaches. Here, we have developed knockin mice recapitulating the most common RTT-associated missense mutation, MeCP2 T158M. We found that the T158M mutation impaired MECP2 binding to methylated DNA and destabilized MeCP2 protein in an age-dependent manner, leading to the development of RTT-like phenotypes in these mice. Genetic elevation of MeCP2 T158M expression ameliorated multiple RTT-like features, including motor dysfunction and breathing irregularities, in both male and female mice. These improvements were accompanied by increased binding of MeCP2 T158M to DNA. Further, we found that the ubiquitin/proteasome pathway was responsible for MeCP2 T158M degradation and that proteasome inhibition increased MeCP2 T158M levels. Together, these findings demonstrate that increasing MeCP2 T158M protein expression is sufficient to mitigate RTT-like phenotypes and support the targeting of MeCP2 T158M expression or stability as an alternative therapeutic approach.
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24
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Schenkel LC, Rodenhiser D, Siu V, McCready E, Ainsworth P, Sadikovic B. Constitutional Epi/Genetic Conditions: Genetic, Epigenetic, and Environmental Factors. J Pediatr Genet 2017; 6:30-41. [PMID: 28180025 PMCID: PMC5288004 DOI: 10.1055/s-0036-1593849] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 04/14/2016] [Indexed: 12/12/2022]
Abstract
There are more than 4,000 phenotypes for which the molecular basis is at least partly known. Though defects in primary DNA structure constitute a major cause of these disorders, epigenetic disruption is emerging as an important alternative mechanism in the etiology of a broad range of congenital and developmental conditions. These include epigenetic defects caused by either localized (in cis) genetic alterations or more distant (in trans) genetic events but can also include environmental effects. Emerging evidence suggests interplay between genetic and environmental factors in the epigenetic etiology of several constitutional "epi/genetic" conditions. This review summarizes our broadening understanding of how epigenetics contributes to pediatric disease by exploring different classes of epigenomic disorders. It further challenges the simplistic dogma of "DNA encodes RNA encodes protein" to best understand the spectrum of factors that can influence genetic traits in a pediatric population.
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Affiliation(s)
- Laila C. Schenkel
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
- Children's Health Research Institute, London, Ontario, Canada
| | - David Rodenhiser
- Children's Health Research Institute, London, Ontario, Canada
- Department of Biochemistry, Western University, London, Ontario, Canada
- Department of Pediatrics, Western University, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
- Department of Oncology, Western University, London, Ontario, Canada
| | - Victoria Siu
- Children's Health Research Institute, London, Ontario, Canada
- Department of Pediatrics, Western University, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
| | - Elizabeth McCready
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Peter Ainsworth
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
- Children's Health Research Institute, London, Ontario, Canada
- Department of Biochemistry, Western University, London, Ontario, Canada
- Department of Pediatrics, Western University, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
- Department of Oncology, Western University, London, Ontario, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
- Children's Health Research Institute, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
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25
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Claveria-Gimeno R, Lanuza PM, Morales-Chueca I, Jorge-Torres OC, Vega S, Abian O, Esteller M, Velazquez-Campoy A. The intervening domain from MeCP2 enhances the DNA affinity of the methyl binding domain and provides an independent DNA interaction site. Sci Rep 2017; 7:41635. [PMID: 28139759 PMCID: PMC5282554 DOI: 10.1038/srep41635] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/22/2016] [Indexed: 01/09/2023] Open
Abstract
Methyl-CpG binding protein 2 (MeCP2) preferentially interacts with methylated DNA and it is involved in epigenetic regulation and chromatin remodelling. Mutations in MeCP2 are linked to Rett syndrome, the leading cause of intellectual retardation in girls and causing mental, motor and growth impairment. Unstructured regions in MeCP2 provide the plasticity for establishing interactions with multiple binding partners. We present a biophysical characterization of the methyl binding domain (MBD) from MeCP2 reporting the contribution of flanking domains to its structural stability and dsDNA interaction. The flanking disordered intervening domain (ID) increased the structural stability of MBD, modified its dsDNA binding profile from an entropically-driven moderate-affinity binding to an overwhelmingly enthalpically-driven high-affinity binding. Additionally, ID provided an additional site for simultaneously and autonomously binding an independent dsDNA molecule, which is a key feature linked to the chromatin remodelling and looping activity of MeCP2, as well as its ability to interact with nucleosomes replacing histone H1. The dsDNA interaction is characterized by an unusually large heat capacity linked to a cluster of water molecules trapped within the binding interface. The dynamics of disordered regions together with extrinsic factors are key determinants of MeCP2 global structural properties and functional capabilities.
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Affiliation(s)
- Rafael Claveria-Gimeno
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, 50018, Spain.,Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, 50009, Spain.,Aragon Institute for Health Research (IIS Aragon), Zaragoza, 50009, Spain
| | - Pilar M Lanuza
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, 50018, Spain.,Aragon Institute for Health Research (IIS Aragon), Zaragoza, 50009, Spain.,Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, Zaragoza, 50009, Spain
| | - Ignacio Morales-Chueca
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, 50018, Spain.,Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, 50009, Spain
| | - Olga C Jorge-Torres
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, 08908, Spain
| | - Sonia Vega
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, 50018, Spain
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, 50018, Spain.,Instituto Aragonés de Ciencias de la Salud (IACS), Zaragoza, 50009, Spain.,Aragon Institute for Health Research (IIS Aragon), Zaragoza, 50009, Spain.,Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, Zaragoza, 50009, Spain.,Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain
| | - Manel Esteller
- Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, 08908, Spain.,Department of Physiological Sciences II, School of Medicine, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, 08907, Spain.,Institucio Catalana de Recerca i Estudis Avançats, Barcelona, 08010, Spain
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, 50018, Spain.,Aragon Institute for Health Research (IIS Aragon), Zaragoza, 50009, Spain.,Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza, Zaragoza, 50009, Spain.,Fundacion ARAID, Government of Aragon, Zaragoza, 50018, Spain
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26
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From Function to Phenotype: Impaired DNA Binding and Clustering Correlates with Clinical Severity in Males with Missense Mutations in MECP2. Sci Rep 2016; 6:38590. [PMID: 27929079 PMCID: PMC5144150 DOI: 10.1038/srep38590] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/11/2016] [Indexed: 11/25/2022] Open
Abstract
Mutations in the MECP2 gene cause Rett syndrome (RTT). MeCP2 binds to chromocentric DNA through its methyl CpG-binding domain (MBD) to regulate gene expression. In heterozygous females the variable phenotypic severity is modulated by non-random X-inactivation, thus making genotype-phenotype comparisons unreliable. However, genotype-phenotype correlations in males with hemizygousMECP2 mutations can provide more accurate insights in to the true biological effect of specific mutations. Here, we compared chromatin organization and binding dynamics for twelve MeCP2 missense mutations (including two novel and the five most common MBD missense RTT mutations) and identifiedacorrelation with phenotype in hemizygous males. We observed impaired interaction of MeCP2-DNA for mutations around the MBD-DNA binding interface, and defective chromatin clustering for distal MBD mutations. Furthermore, binding and mobility dynamics show a gradient of impairment depending on the amino acid properties and tertiary structure within the MBD. Interestingly, a wide range of phenotypic/clinical severity, ranging from neonatal encephalopathy to mild psychiatric abnormalities were observed and all are consistent with our functional/molecular results. Overall, clinical severity showed a direct correlation with the functional impairment of MeCP2. These mechanistic and phenotypic correlations of MeCP2 mutations will enable improved and individualized diagnostics, and may lead to personalized therapeutic interventions.
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27
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Yang Y, Kucukkal TG, Li J, Alexov E, Cao W. Binding Analysis of Methyl-CpG Binding Domain of MeCP2 and Rett Syndrome Mutations. ACS Chem Biol 2016; 11:2706-2715. [PMID: 27356039 PMCID: PMC9860374 DOI: 10.1021/acschembio.6b00450] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Methyl-CpG binding protein 2 (MeCP2) binds to methylated cytosine in CpG island through its methyl-CpG binding domain (MBD). Here, the effects of the Rett syndrome-causing missense mutations on binding affinity of MBD to cytosine (C), methylcytosine (mC), hydroxymethylcytosine (hmC), formylcytosine (fC), and carboxylcytosine (caC) in CpG dinucleotide are investigated. MeCP2-MBD binds to mC-containing variants of double stranded CpG stronger than any other cytosine modified CpG with the strongest affinity to mC/mC. Thirteen MBD missense mutations show reduced binding affinity for mC/mC ranging with a 2-fold decrease for T158M to 88-fold for R111G. The binding affinities of these mutants to C/C are also reduced to various degrees except for T158M. Consistent with free energy perturbation analysis, correlation of binding affinity with protein unfolding allows for grouping mutations into three clusters. Correlation of the first cluster includes mutations that have a higher tendency to unfold and have lesser affinity to mC/mC and C/C. Mutations in the second cluster have similar structural stability but various affinities to mC/mC and C/C. R111G and A140V belong to the third cluster in which the loss of protein flexibility may underlie their reduction in binding affinity to mC/mC and C/C. Most notably, R111 emerges as the key structural element that modulates the specific contacts with mCpG. Implications of the results for the mCpG binding mechanism of MeCP2-MBD are discussed. These analyses provide new insights on the structure and function relationships in MeCP2-MBD and offer new clues to their roles in the pathology of Rett syndrome.
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Affiliation(s)
- Ye Yang
- Department of Genetics and Biochemistry, South Carolina Experiment Station, Clemson University, Room 049 Life Sciences Facility, 190 Collings Street, Clemson, SC 29634, USA
| | - Tugba G. Kucukkal
- Department of Physics, Clemson University, 118 Kinard Laboratory, Clemson, SC 29634, USA
| | - Jing Li
- Department of Genetics and Biochemistry, South Carolina Experiment Station, Clemson University, Room 049 Life Sciences Facility, 190 Collings Street, Clemson, SC 29634, USA
| | - Emil Alexov
- Department of Physics, Clemson University, 118 Kinard Laboratory, Clemson, SC 29634, USA,Corresponding Author: ; Tel.: (864) 656-4176; ; Tel.: 864-908-4796
| | - Weiguo Cao
- Department of Genetics and Biochemistry, South Carolina Experiment Station, Clemson University, Room 049 Life Sciences Facility, 190 Collings Street, Clemson, SC 29634, USA,Corresponding Author: ; Tel.: (864) 656-4176; ; Tel.: 864-908-4796
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28
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Claveria-Gimeno R, Abian O, Velazquez-Campoy A, Ausió J. MeCP2… Nature’s Wonder Protein or Medicine’s Most Feared One? CURRENT GENETIC MEDICINE REPORTS 2016. [DOI: 10.1007/s40142-016-0107-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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29
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Lyst MJ, Connelly J, Merusi C, Bird A. Sequence-specific DNA binding by AT-hook motifs in MeCP2. FEBS Lett 2016; 590:2927-33. [PMID: 27461740 PMCID: PMC5028900 DOI: 10.1002/1873-3468.12328] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 07/20/2016] [Accepted: 07/21/2016] [Indexed: 11/11/2022]
Abstract
MeCP2 is a chromatin‐associated protein that is mutated in Rett syndrome. Its methyl‐CpG‐binding domain interacts with DNA containing methylated cytosine, but other modes of recruitment to the genome have also been proposed. Here, we use in vitro and in vivo assays to investigate the DNA binding specificity of two AT‐hook motifs in MeCP2. One exhibits robust sequence‐specific DNA binding, whereas the other is a much weaker AT‐hook. Our data indicate that these motifs are secondary contributors to DNA binding by MeCP2, and this view is supported by the absence of disease‐causing missense mutations at these sites.
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Affiliation(s)
- Matthew J Lyst
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - John Connelly
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Cara Merusi
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Adrian Bird
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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30
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Brown K, Selfridge J, Lagger S, Connelly J, De Sousa D, Kerr A, Webb S, Guy J, Merusi C, Koerner MV, Bird A. The molecular basis of variable phenotypic severity among common missense mutations causing Rett syndrome. Hum Mol Genet 2015; 25:558-70. [PMID: 26647311 PMCID: PMC4731022 DOI: 10.1093/hmg/ddv496] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/30/2015] [Indexed: 11/18/2022] Open
Abstract
Rett syndrome is caused by mutations in the X-linked MECP2 gene, which encodes a chromosomal protein that binds to methylated DNA. Mouse models mirror the human disorder and therefore allow investigation of phenotypes at a molecular level. We describe an Mecp2 allelic series representing the three most common missense Rett syndrome (RTT) mutations, including first reports of Mecp2[R133C] and Mecp2[T158M] knock-in mice, in addition to Mecp2[R306C] mutant mice. Together these three alleles comprise ∼25% of all RTT mutations in humans, but they vary significantly in average severity. This spectrum is mimicked in the mouse models; R133C being least severe, T158M most severe and R306C of intermediate severity. Both R133C and T158M mutations cause compound phenotypes at the molecular level, combining compromised DNA binding with reduced stability, the destabilizing effect of T158M being more severe. Our findings contradict the hypothesis that the R133C mutation exclusively abolishes binding to hydroxymethylated DNA, as interactions with DNA containing methyl-CG, methyl-CA and hydroxymethyl-CA are all reduced in vivo. We find that MeCP2[T158M] is significantly less stable than MeCP2[R133C], which may account for the divergent clinical impact of the mutations. Overall, this allelic series recapitulates human RTT severity, reveals compound molecular aetiologies and provides a valuable resource in the search for personalized therapeutic interventions.
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Affiliation(s)
- Kyla Brown
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Jim Selfridge
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Sabine Lagger
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - John Connelly
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Dina De Sousa
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Alastair Kerr
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Shaun Webb
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Jacky Guy
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Cara Merusi
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Martha V Koerner
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Adrian Bird
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
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31
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Heimer BW, Tam BE, Sikes HD. Characterization and directed evolution of a methyl-binding domain protein for high-sensitivity DNA methylation analysis. Protein Eng Des Sel 2015; 28:543-51. [PMID: 26384511 PMCID: PMC4646160 DOI: 10.1093/protein/gzv046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 08/06/2015] [Accepted: 08/14/2015] [Indexed: 01/10/2023] Open
Abstract
Methyl-binding domain (MBD) family proteins specifically bind double-stranded, methylated DNA which makes them useful for DNA methylation analysis. We displayed three of the core members MBD1, MBD2 and MBD4 on the surface of Saccharomyces cerevisiae cells. Using the yeast display platform, we determined the equilibrium dissociation constant of human MBD2 (hMBD2) to be 5.9 ± 1.3 nM for binding to singly methylated DNA. The measured affinity for DNA with two methylated sites varied with the distance between the sites. We further used the yeast display platform to evolve the hMBD2 protein for improved binding affinity. Affecting five amino acid substitutions doubled the affinity of the wild-type protein to 3.1 ± 1.0 nM. The most prevalent of these mutations, K161R, occurs away from the DNA-binding site and bridges the N- and C-termini of the protein by forming a new hydrogen bond. The F208Y and L170R mutations added new non-covalent interactions with the bound DNA strand. We finally concatenated the high-affinity MBD variant and expressed it in Escherichia coli as a green fluorescent protein fusion. Concatenating the protein from 1× to 3× improved binding 6-fold for an interfacial binding application.
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Affiliation(s)
- Brandon W Heimer
- Department of Chemical Engineering, Massachusetts Institute of Technology, Building E19-502C, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Brooke E Tam
- Department of Chemical Engineering, Massachusetts Institute of Technology, Building E19-502C, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Hadley D Sikes
- Department of Chemical Engineering, Massachusetts Institute of Technology, Building E19-502C, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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32
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Kucukkal TG, Yang Y, Uvarov O, Cao W, Alexov E. Impact of Rett Syndrome Mutations on MeCP2 MBD Stability. Biochemistry 2015; 54:6357-68. [PMID: 26418480 PMCID: PMC9871983 DOI: 10.1021/acs.biochem.5b00790] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Rett syndrome causing missense mutations in the methyl-CpG-binding domain (MBD) of methyl CpG-binding protein 2 (MeCP2) were investigated both in silico and in vitro to reveal their effect on protein stability. It is demonstrated that the vast majority of frequently occurring mutations in the human population indeed alter the MBD folding free energy by a fraction of a kcal/mol up to more than 1 kcal/mol. While the absolute magnitude of the change of the free energy is small, the effect on the MBD functionality may be substantial since the folding free energy of MBD is about 2 kcal/mol only. Thus, it is emphasized that the effect of mutations on protein integrity should be evaluated with respect to the wild-type folding free energy but not with the absolute value of the folding free energy change. Furthermore, it was observed that the magnitude of the effect is correlated neither with the burial of the mutation sites nor with the basic amino acid physicochemical property change. Mutations that strongly perturb the immediate structural features were found to have little effect on folding free energy, while very conservative mutations resulted in large changes of the MBD stability. This observation was attributed to the protein's ability to structurally relax and reorganize to reduce the effect of mutation. Comparison between in silico and in vitro results indicated that some Web servers perform relatively well, while the free energy perturbation approach frequently overpredicts the magnitude of the free energy change especially when a charged amino acid is involved.
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Affiliation(s)
- Tugba G Kucukkal
- Department of Physics, Clemson University, 118 Kinard Laboratory, Clemson, SC 29634, USA
| | - Ye Yang
- Department of Genetics and Biochemistry, Clemson University, 049 Life Sciences Facility, Clemson, SC 29634, USA
| | - Olga Uvarov
- Department of Genetics and Biochemistry, Clemson University, 049 Life Sciences Facility, Clemson, SC 29634, USA
| | - Weiguo Cao
- Department of Genetics and Biochemistry, Clemson University, 049 Life Sciences Facility, Clemson, SC 29634, USA,Weiguo Cao: , Tel: 864-656-4176; Fax: 864-656-6879, Alexov: , Tel: 864-908-4796, Fax: 864-656-0805
| | - Emil Alexov
- Department of Physics, Clemson University, 118 Kinard Laboratory, Clemson, SC 29634, USA,Weiguo Cao: , Tel: 864-656-4176; Fax: 864-656-6879, Alexov: , Tel: 864-908-4796, Fax: 864-656-0805
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33
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Li Q, Loh DH, Kudo T, Truong D, Derakhshesh M, Kaswan ZM, Ghiani CA, Tsoa R, Cheng Y, Sun YE, Colwell CS. Circadian rhythm disruption in a mouse model of Rett syndrome circadian disruption in RTT. Neurobiol Dis 2015; 77:155-64. [PMID: 25779967 DOI: 10.1016/j.nbd.2015.03.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 03/08/2015] [Accepted: 03/09/2015] [Indexed: 12/14/2022] Open
Abstract
Disturbances in the sleep/wake cycle are prevalent in patients with Rett syndrome (RTT). We sought to determine whether the circadian system is disrupted in a RTT model, Mecp2(-/y) mice. We found that MeCP2 mutants showed decreased strength and precision of daily rhythms of activity coupled with extremely fragmented sleep. The central circadian clock (suprachiasmatic nucleus) exhibited significant reduction in the number of neurons expressing vasoactive intestinal peptide (VIP) as well as compromised spontaneous neural activity. The molecular clockwork was disrupted both centrally in the SCN and in peripheral organs, indicating a general disorganization of the circadian system. Disruption of the molecular clockwork was observed in fibroblasts of RTT patients. Finally, MeCP2 mutant mice were vulnerable to circadian disruption as chronic jet lag accelerated mortality. Our finds suggest an integral role of MeCP2 in the circadian timing system and provides a possible mechanistic explanation for the sleep/wake distrubances observed in RTT patients. The work raises the possibility that RTT patients may benefit from a temporally structured environment.
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Affiliation(s)
- Quan Li
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA; Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA; Molecular, Cellular and Integrative Physiology Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Dawn H Loh
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Takashi Kudo
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Danny Truong
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Matthew Derakhshesh
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Zoë MacDowell Kaswan
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Cristina A Ghiani
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA
| | - Rosemarie Tsoa
- Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA
| | - Yin Cheng
- Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA
| | - Yi E Sun
- Department of Psychiatry, University of California, Los Angeles, Box 957332, 635 S. Charles E. Young Dr, Los Angeles, CA 90095-7332, USA.
| | - Christopher S Colwell
- Laboratory of Circadian and Sleep Medicine, Department of Psychiatry, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles 90095-1759, USA.
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Structural, Dynamical, and Energetical Consequences of Rett Syndrome Mutation R133C in MeCP2. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:746157. [PMID: 26064184 PMCID: PMC4431600 DOI: 10.1155/2015/746157] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/11/2015] [Indexed: 12/25/2022]
Abstract
Rett Syndrome (RTT) is a progressive neurodevelopmental disease affecting females. RTT is caused by mutations in the MECP2 gene and various amino acid substitutions have been identified clinically in different domains of the multifunctional MeCP2 protein encoded by this gene. The R133C variant in the methylated-CpG-binding domain (MBD) of MeCP2 is the second most common disease-causing mutation in the MBD. Comparative molecular dynamics simulations of R133C mutant and wild-type MBD have been performed to understand the impact of the mutation on structure, dynamics, and interactions of the protein and subsequently understand the disease mechanism. Two salt bridges within the protein and two critical hydrogen bonds between the protein and DNA are lost upon the R133C mutation. The mutation was found to weaken the interaction with DNA and also cause loss of helicity within the 141-144 region. The structural, dynamical, and energetical consequences of R133C mutation were investigated in detail at the atomic resolution. Several important implications of this have been shown regarding protein stability and hydration dynamics as well as its interaction with DNA. The results are in agreement with previous experimental studies and further provide atomic level understanding of the molecular origin of RTT associated with R133C variant.
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MTHFR Gene C677T Polymorphism in Autism Spectrum Disorders. GENETICS RESEARCH INTERNATIONAL 2014; 2014:698574. [PMID: 25431675 PMCID: PMC4241316 DOI: 10.1155/2014/698574] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/22/2014] [Accepted: 10/23/2014] [Indexed: 11/18/2022]
Abstract
Aim. Autism is a subgroup of autism spectrum disorders, classified as a heterogeneous neurodevelopmental disorder and symptoms occur in the first three years of life. The etiology of autism is largely unknown, but it has been accepted that genetic and environmental factors may both be responsible for the disease. Recent studies have revealed that the genes involved in the folate/homocysteine pathway may be risk factors for autistic children. In particular, C677T polymorphism in the MTHFR gene as a possible risk factor for autism is still controversial. We aimed to investigate the possible effect of C677T polymorphism in a Turkish cohort. Methods. Autism patients were diagnosed by child psychiatrists according to DSM-IV and DSM-V criteria. A total of 98 children diagnosed as autistic and 70 age and sex-matched children who are nonautistic were tested for C677T polymorphism. This polymorphism was studied by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. Results. MTHFR 677T-allele frequency was found to be higher in autistic children compared with nonautistic children (29% versus 24%), but it was not found statistically significant. Conclusions. We conclude that other MTHFR polymorphisms such as A1298C or other folate/homocysteine pathway genes may be studied to show their possible role in autism.
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Computational and experimental approaches to reveal the effects of single nucleotide polymorphisms with respect to disease diagnostics. Int J Mol Sci 2014; 15:9670-717. [PMID: 24886813 PMCID: PMC4100115 DOI: 10.3390/ijms15069670] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/15/2014] [Accepted: 05/16/2014] [Indexed: 12/25/2022] Open
Abstract
DNA mutations are the cause of many human diseases and they are the reason for natural differences among individuals by affecting the structure, function, interactions, and other properties of DNA and expressed proteins. The ability to predict whether a given mutation is disease-causing or harmless is of great importance for the early detection of patients with a high risk of developing a particular disease and would pave the way for personalized medicine and diagnostics. Here we review existing methods and techniques to study and predict the effects of DNA mutations from three different perspectives: in silico, in vitro and in vivo. It is emphasized that the problem is complicated and successful detection of a pathogenic mutation frequently requires a combination of several methods and a knowledge of the biological phenomena associated with the corresponding macromolecules.
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37
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Huidobro C, Fernandez AF, Fraga MF. The role of genetics in the establishment and maintenance of the epigenome. Cell Mol Life Sci 2013; 70:1543-73. [PMID: 23474979 PMCID: PMC11113764 DOI: 10.1007/s00018-013-1296-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 12/19/2022]
Abstract
Epigenetic mechanisms play an important role in gene regulation during development. DNA methylation, which is probably the most important and best-studied epigenetic mechanism, can be abnormally regulated in common pathologies, but the origin of altered DNA methylation remains unknown. Recent research suggests that these epigenetic alterations could depend, at least in part, on genetic mutations or polymorphisms in DNA methyltransferases and certain genes encoding enzymes of the one-carbon metabolism pathway. Indeed, the de novo methyltransferase 3B (DNMT3B) has been recently found to be mutated in several types of cancer and in the immunodeficiency, centromeric region instability and facial anomalies syndrome (ICF), in which these mutations could be related to the loss of global DNA methylation. In addition, mutations in glycine-N-methyltransferase (GNMT) could be associated with a higher risk of hepatocellular carcinoma and liver disease due to an unbalanced S-adenosylmethionine (SAM)/S-adenosylhomocysteine (SAH) ratio, which leads to aberrant methylation reactions. Also, genetic variants of chromatin remodeling proteins and histone tail modifiers are involved in genetic disorders like α thalassemia X-linked mental retardation syndrome, CHARGE syndrome, Cockayne syndrome, Rett syndrome, systemic lupus erythematous, Rubinstein-Taybi syndrome, Coffin-Lowry syndrome, Sotos syndrome, and facioescapulohumeral syndrome, among others. Here, we review the potential genetic alterations with a possible role on epigenetic factors and discuss their contribution to human disease.
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Affiliation(s)
- Covadonga Huidobro
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Agustin F. Fernandez
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Mario F. Fraga
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
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Casas-Delucchi CS, Becker A, Bolius JJ, Cardoso MC. Targeted manipulation of heterochromatin rescues MeCP2 Rett mutants and re-establishes higher order chromatin organization. Nucleic Acids Res 2012; 40:e176. [PMID: 22923521 PMCID: PMC3526307 DOI: 10.1093/nar/gks784] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Heterochromatic regions represent a significant portion of the mammalian genome and have been implied in several important cellular processes, including cell division and genomic stability. However, its composition and dynamics remain largely unknown. To better understand how heterochromatin functions and how it is organized within the context of the cell nucleus, we have developed molecular tools allowing the targeting of virtually any nuclear factor specifically to heterochromatic regions and, thereby, the manipulation, also in a temporally controlled manner, of its composition. To validate our approach, we have ectopically targeted MeCP2 chromatin binding deficient Rett mutants to constitutive heterochromatic regions and analyze its functional consequences. We could show that, once bound to their endogenous target regions, their ability to re-organize higher order chromatin structure is restored. Furthermore, a temporally controlled targeting strategy allowed us to monitor MeCP2-mediated chromatin rearrangements in vivo and to visualize large-scale chromatin movements over several micrometers, as well as heterochromatic foci fusion events. This novel strategy enables specific tethering of any protein to heterochromatin and lays the ground for controlled manipulation of its composition and organization.
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39
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Hite KC, Kalashnikova AA, Hansen JC. Coil-to-helix transitions in intrinsically disordered methyl CpG binding protein 2 and its isolated domains. Protein Sci 2012; 21:531-8. [PMID: 22294343 DOI: 10.1002/pro.2037] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 12/25/2011] [Accepted: 12/27/2011] [Indexed: 11/08/2022]
Abstract
Methyl CpG binding protein 2 (MeCP2) is a canonical intrinsically disordered protein (IDP), that is, it lacks stable secondary structure throughout its entire polypeptide chain. Because IDPs often have the propensity to become locally ordered, we tested whether full-length MeCP2 and its constituent domains would gain secondary structure in 2,2,2-trifluoroethanol (TFE), a cosolvent that stabilizes intramolecular hydrogen bonding in proteins. The α-helix, β-strand/turn, and unstructured content were determined as a function of TFE concentration by deconvolution of circular dichroism data. Results indicate that approximately two-thirds of the unstructured residues present in full-length MeCP2 were converted to α-helix in 70% TFE without a change in β-strand/turn. Thus, much of the MeCP2 polypeptide chain undergoes coil-to-helix transitions under conditions that favor intrachain hydrogen bond formation. The unstructured residues of the N-terminal (NTD) and C-terminal (CTD) domains were partially converted to α-helix in 70% TFE. In contrast, the central transcription regulation domain (TRD) became almost completely α-helical in 70% TFE. Unlike the NTD, CTD, and TRD, the unstructured content of the methyl DNA binding domain and the intervening domain did not change with increasing TFE concentration. These results indicate that the coil-to-helix transitions that occur in full-length MeCP2 are localized to the NTD, CTD, and TRD, with the TRD showing the greatest tendency for helix formation. The potential relationships between intrinsic disorder, coil-to-helix transitions, and MeCP2 structure and function are discussed.
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Affiliation(s)
- Kristopher C Hite
- Department of Biochemistry and Molecular Biology, Campus Delivery 1870, Colorado State University, Fort Collins, Colorado 80523, USA
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40
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Hansen JC, Ghosh RP, Woodcock CL. Binding of the Rett syndrome protein, MeCP2, to methylated and unmethylated DNA and chromatin. IUBMB Life 2011; 62:732-8. [PMID: 21031501 DOI: 10.1002/iub.386] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Methylated CpG Binding Protein 2 (MeCP2) is a nuclear protein named for its ability to selectively recognize methylated DNA. Much attention has been focused on understanding MeCP2 structure and function in the context of its role in Rett syndrome, a severe neurodevelopmental disorder that afflicts one in 10,000-15,000 girls. Early studies suggested a connection between DNA methylation, MeCP2, and establishment of a repressive chromatin structure at specific gene promoters. However, it is now recognized that MeCP2 can both activate and repress specific genes depending on the context. Likewise, in the cell, MeCP2 is bound to unmethylated DNA and chromatin in addition to methylated DNA. Thus, to understand the molecular basis of MeCP2 functionality, it is necessary to unravel the complex interrelationships between MeCP2 binding to unmethylated and methylated regions of the genome. MeCP2 is unusual and interesting in that it is an intrinsically disordered protein, that is, much of its primary sequence fails to fold into secondary structure and yet is functional. The unique structure of MeCP2 is the subject of the first section of this article. We then discuss recent investigations of the in vitro binding of MeCP2 to unmethylated and methylated DNA, and the potential ramifications of this work for in vivo function. We close by focusing on mechanistic studies indicating that the binding of MeCP2 to chromatin results in compaction into local (secondary) and global (tertiary) higher order structures. MeCP2 also competes with histone H1 for nucleosomal binding sites. The recent finding that MeCP2 is found at near stoichiometric levels with nucleosomes in neuronal cells underscores the multiple modes of engagement of MeCP2 with the genome, which include the cooperative tracking of methylation density.
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Affiliation(s)
- Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.
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41
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Fendri-Kriaa N, Hsairi I, Kifagi C, Ellouze E, Mkaouar-Rebai E, Triki C, Fakhfakh F. A case of a Tunisian Rett patient with a novel double-mutation of the MECP2 gene. Biochem Biophys Res Commun 2011; 409:270-4. [PMID: 21575601 DOI: 10.1016/j.bbrc.2011.04.140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 04/29/2011] [Indexed: 11/18/2022]
Abstract
Rett syndrome is an X-linked dominant disorder caused frequently by mutations in the methyl-CpG-binding protein 2 gene (MECP2). Rett patients present an apparently normal psychomotor development during the first 6-18 months of life. Thereafter, they show a short period of developmental stagnation followed by a rapid regression in language and motor development. The aim of this study was to perform a mutational analysis of the MECP2 gene in a classical Rett patient by sequencing the corresponding gene and modeling the found variants. The results showed the presence of a double-mutation: a new and de novo mutation c.535C>T (p.P179S) and the common c.763C>T (p.R255X) transition of the MECP2 gene. The p.P179S mutation was located in a conserved amino acid in CRIR domain (corepressor interacting region). Modeling results showed that the P179S transition could change local electrostatic properties by adding a negative charge due to serine hydroxyl group of this region of MeCP2 which may affect the function and stability of the protein. The p.R255X mutation is located in TRD-NLS domain (transcription repression domain-nuclear localization signal) of MeCP2 protein.
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Affiliation(s)
- Nourhene Fendri-Kriaa
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Université de Sfax, Tunisia.
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Hansen JC, Wexler BB, Rogers DJ, Hite KC, Panchenko T, Ajith S, Black BE. DNA binding restricts the intrinsic conformational flexibility of methyl CpG binding protein 2 (MeCP2). J Biol Chem 2011; 286:18938-48. [PMID: 21467044 PMCID: PMC3099709 DOI: 10.1074/jbc.m111.234609] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 03/29/2011] [Indexed: 12/23/2022] Open
Abstract
Mass spectrometry-based hydrogen/deuterium exchange (H/DX) has been used to define the polypeptide backbone dynamics of full-length methyl CpG binding protein 2 (MeCP2) when free in solution and when bound to unmethylated and methylated DNA. Essentially the entire MeCP2 polypeptide chain underwent H/DX at rates faster than could be measured (i.e. complete exchange in ≤10 s), with the exception of the methyl DNA binding domain (MBD). Even the H/DX of the MBD was rapid compared with that of a typical globular protein. Thus, there is no single tertiary structure of MeCP2. Rather, the full-length protein rapidly samples many different conformations when free in solution. When MeCP2 binds to unmethylated DNA, H/DX is slowed several orders of magnitude throughout the MBD. Binding of MeCP2 to methylated DNA led to additional minor H/DX protection, and only locally within the N-terminal portion of the MBD. H/DX also was used to examine the structural dynamics of the isolated MBD carrying three frequent mutations associated with Rett syndrome. The effects of the mutations ranged from very little (R106W) to a substantial increase in conformational sampling (F155S). Our H/DX results have yielded fine resolution mapping of the structure of full-length MeCP2 in the absence and presence of DNA, provided a biochemical basis for understanding MeCP2 function in normal cells, and predicted potential approaches for the treatment of a subset of RTT cases caused by point mutations that destabilize the MBD.
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Affiliation(s)
- Jeffrey C. Hansen
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | | | | | - Kristopher C. Hite
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870
| | - Tanya Panchenko
- the Department of Biochemistry and Biophysics
- Graduate Group in Cell and Molecular Biology, and
| | - Sandya Ajith
- the Department of Biochemistry and Biophysics
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059
| | - Ben E. Black
- the Department of Biochemistry and Biophysics
- Graduate Group in Cell and Molecular Biology, and
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059
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43
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The molecular genetics of autism spectrum disorders: genomic mechanisms, neuroimmunopathology, and clinical implications. AUTISM RESEARCH AND TREATMENT 2011; 2011:398636. [PMID: 22937247 PMCID: PMC3420760 DOI: 10.1155/2011/398636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Accepted: 03/29/2011] [Indexed: 11/17/2022]
Abstract
Autism spectrum disorders (ASDs) have become increasingly common in recent years. The discovery of single-nucleotide polymorphisms and accompanying copy number variations within the genome has increased our understanding of the architecture of the disease. These genetic and genomic alterations coupled with epigenetic phenomena have pointed to a neuroimmunopathological mechanism for ASD. Model animal studies, developmental biology, and affective neuroscience laid a foundation for dissecting the neural pathways impacted by these disease-generating mechanisms. The goal of current autism research is directed toward a systems biological approach to find the most basic genetic and environmental causes to this severe developmental disease. It is hoped that future genomic and neuroimmunological research will be directed toward finding the road toward prevention, treatment, and cure of ASD.
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44
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Scarsdale JN, Webb HD, Ginder GD, Williams DC. Solution structure and dynamic analysis of chicken MBD2 methyl binding domain bound to a target-methylated DNA sequence. Nucleic Acids Res 2011; 39:6741-52. [PMID: 21531701 PMCID: PMC3159451 DOI: 10.1093/nar/gkr262] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The epigenetic code of DNA methylation is interpreted chiefly by methyl cytosine binding domain (MBD) proteins which in turn recruit multiprotein co-repressor complexes. We previously isolated one such complex, MBD2-NuRD, from primary erythroid cells and have shown it contributes to embryonic/fetal β-type globin gene silencing during development. This complex has been implicated in silencing tumor suppressor genes in a variety of human tumor cell types. Here we present structural details of chicken MBD2 bound to a methylated DNA sequence from the ρ-globin promoter to which it binds in vivo and mediates developmental transcriptional silencing in normal erythroid cells. While previous studies have failed to show sequence specificity for MBD2 outside of the symmetric mCpG, we find that this domain binds in a single orientation on the ρ-globin target DNA sequence. Further, we show that the orientation and affinity depends on guanine immediately following the mCpG dinucleotide. Dynamic analyses show that DNA binding stabilizes the central β-sheet, while the N- and C-terminal regions of the protein maintain mobility. Taken together, these data lead to a model in which DNA binding stabilizes the MBD2 structure and that binding orientation and affinity is influenced by the DNA sequence surrounding the central mCpG.
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Affiliation(s)
- J Neel Scarsdale
- Institute of Structural Biology and Drug Design, Virginia Commonwealth University, Richmond, VA 23298-0035, USA
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45
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Calfa G, Percy AK, Pozzo-Miller L. Experimental models of Rett syndrome based on Mecp2 dysfunction. Exp Biol Med (Maywood) 2011; 236:3-19. [PMID: 21239731 DOI: 10.1258/ebm.2010.010261] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder predominantly occurring in females with an incidence of 1:10,000 births and caused by sporadic mutations in the MECP2 gene, which encodes methyl-CpG-binding protein-2, an epigenetic transcription factor that binds methylated DNA. The clinical hallmarks include a period of apparently normal early development followed by a plateau and then subsequent frank regression. Impaired visual and aural contact often lead to an initial diagnosis of autism. The characterization of experimental models based on the loss-of-function of the mouse Mecp2 gene revealed that subtle changes in the morphology and function of brain cells and synapses have profound consequences on network activities that underlie critical brain functions. Furthermore, these experimental models have been used for successful reversals of RTT-like symptoms by genetic, pharmacological and environmental manipulations, raising hope for novel therapeutic strategies to improve the quality of life of RTT individuals.
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Affiliation(s)
- Gaston Calfa
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
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46
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Liu X, Solehdin F, Cohen IL, Gonzalez MG, Jenkins EC, Lewis MES, Holden JJA. Population- and Family-Based Studies Associate the MTHFR Gene with Idiopathic Autism in Simplex Families. J Autism Dev Disord 2010; 41:938-44. [DOI: 10.1007/s10803-010-1120-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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47
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MeCP2 binds cooperatively to its substrate and competes with histone H1 for chromatin binding sites. Mol Cell Biol 2010; 30:4656-70. [PMID: 20679481 DOI: 10.1128/mcb.00379-10] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sporadic mutations in the hMeCP2 gene, coding for a protein that preferentially binds symmetrically methylated CpGs, result in the severe neurological disorder Rett syndrome (RTT). In the present work, employing a wide range of experimental approaches, we shed new light on the many levels of MeCP2 interaction with DNA and chromatin. We show that strong methylation-independent as well as methylation-dependent binding by MeCP2 is influenced by DNA length. Although MeCP2 is strictly monomeric in solution, its binding to DNA is cooperative, with dimeric binding strongly correlated with methylation density, and strengthened by nearby A/T repeats. Dimeric binding is abolished in the F155S and R294X severe RTT mutants. MeCP2 also binds chromatin in vitro, resulting in compaction-related changes in nucleosome architecture that resemble the classical zigzag motif induced by histone H1 and considered important for 30-nm-fiber formation. In vivo chromatin binding kinetics and in vitro steady-state nucleosome binding of both MeCP2 and H1 provide strong evidence for competition between MeCP2 and H1 for common binding sites. This suggests that chromatin binding by MeCP2 and H1 in vivo should be viewed in the context of competitive multifactorial regulation.
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48
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Ghosh RP, Nikitina T, Horowitz-Scherer RA, Gierasch LM, Uversky VN, Hite K, Hansen JC, Woodcock CL. Unique physical properties and interactions of the domains of methylated DNA binding protein 2. Biochemistry 2010; 49:4395-410. [PMID: 20405910 DOI: 10.1021/bi9019753] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methylated DNA binding protein 2 (MeCP2) is a methyl CpG binding protein whose key role is the recognition of epigenetic information encoded in DNA methylation patterns. Mutation or misregulation of MeCP2 function leads to Rett syndrome as well as a variety of other autism spectrum disorders. Here, we have analyzed in detail the properties of six individually expressed human MeCP2 domains spanning the entire protein with emphasis on their interactions with each other, with DNA, and with nucleosomal arrays. Each domain contributes uniquely to the structure and function of the full-length protein. MeCP2 is approximately 60% unstructured, with nine interspersed alpha-molecular recognition features (alpha-MoRFs), which are polypeptide segments predicted to acquire secondary structure upon forming complexes with binding partners. Large increases in secondary structure content are induced in some of the isolated MeCP2 domains and in the full-length protein by binding to DNA. Interactions between some MeCP2 domains in cis and trans seen in our assays likely contribute to the structure and function of the intact protein. We also show that MeCP2 has two functional halves. The N-terminal portion contains the methylated DNA binding domain (MBD) and two highly disordered flanking domains that modulate MBD-mediated DNA binding. One of these flanking domains is also capable of autonomous DNA binding. In contrast, the C-terminal portion of the protein that harbors at least two independent DNA binding domains and a chromatin-specific binding domain is largely responsible for mediating nucleosomal array compaction and oligomerization. These findings led to new mechanistic and biochemical insights regarding the conformational modulations of this intrinsically disordered protein, and its context-dependent in vivo roles.
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Affiliation(s)
- Rajarshi P Ghosh
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Fenech MF. Dietary reference values of individual micronutrients and nutriomes for genome damage prevention: current status and a road map to the future. Am J Clin Nutr 2010; 91:1438S-1454S. [PMID: 20219957 DOI: 10.3945/ajcn.2010.28674d] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Damage to the genome is recognized as a fundamental cause of developmental and degenerative diseases. Several micronutrients play an important role in protecting against DNA damage events generated through endogenous and exogenous factors by acting as cofactors or substrates for enzymes that detoxify genotoxins as well as enzymes involved in DNA repair, methylation, and synthesis. In addition, it is evident that either micronutrient deficiency or micronutrient excess can modify genome stability and that these effects may also depend on nutrient-nutrient and nutrient-gene interaction, which is affected by genotype. These observations have led to the emerging science of genome health nutrigenomics, which is based on the principle that DNA damage is a fundamental cause of disease that can be diagnosed and nutritionally prevented on an individual, genetic subgroup, or population basis. In this article, the following topics are discussed: 1) biomarkers used to study genome damage in humans and their validation, 2) evidence for the association of genome damage with developmental and degenerative disease, 3) current knowledge of micronutrients required for the maintenance of genome stability in humans, 4) the effect of nutrient-nutrient and nutrient-genotype interaction on DNA damage, and 5) strategies to determine dietary reference values of single micronutrients and micronutrient combinations (nutriomes) on the basis of DNA damage prevention. This article also identifies important knowledge gaps and future research directions required to shed light on these issues. The ultimate goal is to match the nutriome to the genome to optimize genome maintenance and to prevent pathologic amounts of DNA damage.
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Affiliation(s)
- Michael F Fenech
- Commonwealth Scientific and Industrial Research Organisation Food and Nutritional Sciences, Adelaide BC SA 5000, Australia.
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Condie J, Goldstein J, Wainwright MS. Acquired microcephaly, regression of milestones, mitochondrial dysfunction, and episodic rigidity in a 46,XY male with a de novo MECP2 gene mutation. J Child Neurol 2010; 25:633-6. [PMID: 20142466 DOI: 10.1177/0883073809342004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We report a case of acquired microcephaly in a male infant. Testing for mutations in the MECP2 gene identified a de novo hemizygous c.378-3C>G mutation at a highly conserved 3' splice site, consistent with Rett syndrome. Other distinctive features included periodic hypertonicity, decreased mitochondrial complex III activity, and abnormal magnetic resonance imaging (MRI) T2 signal in the pons. Rett syndrome was originally described in females with a clinical phenotype of deceleration of head growth, abnormal hand movements, and developmental regression. The clinical diagnosis can now be supported by genetic testing for MECP2 mutations, and the phenotype of disorder has expanded. Cases of Rett syndrome in males are rare and a total of 17 such cases have been reported. This case extends the clinical phenotype of Rett syndrome in males and associates this mutation with mitochondrial dysfunction.
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Affiliation(s)
- John Condie
- Department of Pediatrics, Division of Neurology, Children's Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA
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