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Hu Y, Lauffer P, Jongejan A, Falize K, Bruinstroop E, van Trotsenburg P, Fliers E, Hennekam RC, Boelen A. Analysis of genes differentially expressed in the cortex of mice with the Tbl1xr1 Y446C/Y446C variant. Gene 2024; 927:148707. [PMID: 38885822 DOI: 10.1016/j.gene.2024.148707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 06/09/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024]
Abstract
Transducin β-like 1 X-linked receptor 1 (mouse Tbl1xr1) or TBL1X/Y related 1 (human TBL1XR1), part of the NCoR/SMRT corepressor complex, is involved in nuclear receptor signaling. Variants in TBL1XR1 cause a variety of neurodevelopmental disorders including Pierpont syndrome caused by the p.Tyr446Cys variant. We recently reported a mouse model carrying the Tbl1xr1Y446C/Y446C variant as a model for Pierpont syndrome. To obtain insight into mechanisms involved in altered brain development we studied gene expression patterns in the cortex of mutant and wild type (WT) mice, using RNA-sequencing, differentially expressed gene (DEG) analysis, gene set enrichment analysis (GSEA), weighted gene correlation network analysis (WGCNA) and hub gene analysis. We validated results in mutated mouse cortex, as well as in BV2 and SK-N-AS cell lines, in both of which Tbl1xr1 was knocked down by siRNA. Two DEGs (adj.P. Val < 0.05) were found in the cortex, Mpeg1 (downregulated in mutant mice) and 2900052N01Rik (upregulated in mutant mice). GSEA, WGCNA and hub gene analysis demonstrated changes in genes involved in ion channel function and neuroinflammation in the cortex of the Tbl1xr1Y446C/Y446C mice. The lowered expression of ion channel genes Kcnh3 and Kcnj4 mRNA was validated in the mutant mouse cortex, and increased expression of TRIM9, associated with neuroinflammation, was confirmed in the SK-N-AS cell line. Conclusively, our results show altered expression of genes involved in ion channel function and neuroinflammation in the cortex of the Tbl1xr1Y446C/Y446C mice. These may partly explain the impaired neurodevelopment observed in individuals with Pierpont syndrome and related TBL1XR1-related disorders.
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Affiliation(s)
- Yalan Hu
- Endocrine Laboratory, Department of Laboratory Medicine, Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Peter Lauffer
- Department of Pediatric Endocrinology, Emma Children's Hospital, University of Amsterdam, Amsterdam, the Netherlands; Research Institute Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Aldo Jongejan
- Department of Epidemiology and Data Science, Bioinformatics Laboratory, Amsterdam UMC Location AMC, University of Amsterdam, Amsterdam, the Netherlands; Research Institute Amsterdam Public Health, Methodology, Amsterdam, the Netherlands
| | - Kim Falize
- Endocrine Laboratory, Department of Laboratory Medicine, Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Eveline Bruinstroop
- Research Institute Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Paul van Trotsenburg
- Department of Pediatric Endocrinology, Emma Children's Hospital, University of Amsterdam, Amsterdam, the Netherlands; Research Institute Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Eric Fliers
- Research Institute Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Raoul C Hennekam
- Department of Pediatrics, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Anita Boelen
- Endocrine Laboratory, Department of Laboratory Medicine, Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Research Institute Amsterdam Gastroenterology, Endocrinology & Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
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2
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Beribisky AV, Huber A, Sarne V, Spittler A, Sukhbaatar N, Seipel T, Laccone F, Steinkellner H. MeCP2 is a naturally supercharged protein with cell membrane transduction capabilities. Protein Sci 2024; 33:e5170. [PMID: 39276009 PMCID: PMC11400631 DOI: 10.1002/pro.5170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 08/23/2024] [Accepted: 08/26/2024] [Indexed: 09/16/2024]
Abstract
The intrinsically disordered protein MeCP2 is a global transcriptional regulator encoded by the MECP2 gene. Although the structured domains of MeCP2 have been the subject of multiple studies, its unstructured regions have not been that extensively characterized. In this work, we show that MeCP2 possesses properties akin to those of supercharged proteins. By utilizing its unstructured portions, MeCP2 can successfully transduce across cell membranes and localize to heterochromatic foci in the nuclei, displaying uptake levels a third lower than a MeCP2 construct fused to the cell-penetrating peptide TAT. MeCP2 uptake can further be enhanced by the addition of compounds that promote endosomal escape following cellular trafficking by means of macropinocytosis. Using a combination of in silico prediction algorithms and live-cell imaging experiments, we mapped the sequence in MeCP2 responsible for its cellular incorporation, which bears a striking resemblance to TAT itself. Transduced MeCP2 was shown to interact with HDAC3. These findings provide valuable insight into the properties of MeCP2 and may be beneficial for devising future protein-based treatment strategies.
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Affiliation(s)
- Alexander V Beribisky
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Anna Huber
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
- Vienna Doctoral School of Pharmaceutical, Nutritional and Sport Sciences (PhaNuSpo), University of Vienna, Vienna, Austria
| | - Victoria Sarne
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
- Vienna Doctoral School of Pharmaceutical, Nutritional and Sport Sciences (PhaNuSpo), University of Vienna, Vienna, Austria
| | - Andreas Spittler
- Core Facility Flow Cytometry & Department of Surgery, Research Laboratories, Vienna, Austria
| | - Nyamdelger Sukhbaatar
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Teresa Seipel
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Franco Laccone
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
| | - Hannes Steinkellner
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Vienna, Austria
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3
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Carrazana R, Espinoza F, Ávila A. Mechanistic perspective on the actions of vitamin a in autism spectrum disorder etiology. Neuroscience 2024; 554:72-82. [PMID: 39002756 DOI: 10.1016/j.neuroscience.2024.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 05/07/2024] [Accepted: 07/08/2024] [Indexed: 07/15/2024]
Abstract
Vitamin A (VA) has many functions in the body, some of which are key for the development and functioning of the nervous system, while some others might indirectly influence neural function. Both hypovitaminosis and hypervitaminosis A can lead to clinical manifestations of concern for individuals and for general global health. Scientific evidence on the link between VA and autism spectrum disorder (ASD) is growing, with some clinical studies and accumulating results obtained from basic research using cellular and animal models. Remarkably, it has been shown that VA deficiency can exacerbate autistic symptomatology. In turn, VA supplementation has been shown to be able to improve autistic symptomatology in selected groups of individuals with ASD. However, it is important to recognize that ASD is a highly heterogeneous condition. Therefore, it is important to clarify how and when VA supplementation can be of benefit for affected individuals. Here we delve into the relationship between VA and ASD, discussing clinical observations and mechanistic insights obtained from research on selected autistic syndromes and laboratory models to advance in defining how the VA signaling pathway can be exploited for treatment of ASD.
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Affiliation(s)
- Ramón Carrazana
- Neurodevelopmental Biology Unit, Biomedical Sciences Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Francisca Espinoza
- Neurodevelopmental Biology Unit, Biomedical Sciences Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Ariel Ávila
- Neurodevelopmental Biology Unit, Biomedical Sciences Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile.
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4
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Chua GNL, Watters JW, Olinares PDB, Begum M, Vostal LE, Luo JA, Chait BT, Liu S. Differential dynamics specify MeCP2 function at nucleosomes and methylated DNA. Nat Struct Mol Biol 2024:10.1038/s41594-024-01373-9. [PMID: 39164525 DOI: 10.1038/s41594-024-01373-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 07/16/2024] [Indexed: 08/22/2024]
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is an essential chromatin-binding protein whose mutations cause Rett syndrome (RTT), a severe neurological disorder that primarily affects young females. The canonical view of MeCP2 as a DNA methylation-dependent transcriptional repressor has proven insufficient to describe its dynamic interaction with chromatin and multifaceted roles in genome organization and gene expression. Here we used single-molecule correlative force and fluorescence microscopy to directly visualize the dynamics of wild-type and RTT-causing mutant MeCP2 on DNA. We discovered that MeCP2 exhibits distinct one-dimensional diffusion kinetics when bound to unmethylated versus CpG methylated DNA, enabling methylation-specific activities such as co-repressor recruitment. We further found that, on chromatinized DNA, MeCP2 preferentially localizes to nucleosomes and stabilizes them from mechanical perturbation. Our results reveal the multimodal behavior of MeCP2 on chromatin that underlies its DNA methylation- and nucleosome-dependent functions and provide a biophysical framework for dissecting the molecular pathology of RTT mutations.
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Affiliation(s)
- Gabriella N L Chua
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
| | - John W Watters
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Masuda Begum
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Lauren E Vostal
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA
| | - Joshua A Luo
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
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5
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Kalani L, Kim BH, de Chavez AR, Roemer A, Mikhailov A, Merritt JK, Good KV, Chow RL, Delaney KR, Hendzel MJ, Zhou Z, Neul JL, Vincent JB, Ausió J. Testing the PEST hypothesis using relevant Rett mutations in MeCP2 E1 and E2 isoforms. Hum Mol Genet 2024:ddae119. [PMID: 39137370 DOI: 10.1093/hmg/ddae119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 07/19/2024] [Accepted: 08/07/2024] [Indexed: 08/15/2024] Open
Abstract
Mutations in methyl-CpG binding protein 2 (MeCP2), such as the T158M, P152R, R294X, and R306C mutations, are responsible for most Rett syndrome (RTT) cases. These mutations often result in altered protein expression that appears to correlate with changes in the nuclear size; however, the molecular details of these observations are poorly understood. Using a C2C12 cellular system expressing human MeCP2-E1 isoform as well as mouse models expressing these mutations, we show that T158M and P152R result in a decrease in MeCP2 protein, whereas R306C has a milder variation, and R294X resulted in an overall 2.5 to 3 fold increase. We also explored the potential involvement of the MeCP2 PEST domains in the proteasome-mediated regulation of MeCP2. Finally, we used the R294X mutant to gain further insight into the controversial competition between MeCP2 and histone H1 in the chromatin context. Interestingly, in R294X, MeCP2 E1 and E2 isoforms were differently affected, where the E1 isoform contributes to much of the overall protein increase observed, while E2 decreases by half. The modes of MeCP2 regulation, thus, appear to be differently regulated in the two isoforms.
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Affiliation(s)
- Ladan Kalani
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
| | - Bo-Hyun Kim
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
| | - Alberto Ruiz de Chavez
- Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
| | - Anastasia Roemer
- Departments of Oncology and Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Ave, Edmonton, AB T6G 2H7, Canada
| | - Anna Mikhailov
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College St, Toronto, ON M5T 1R8, Canada
| | - Jonathan K Merritt
- Vanderbilt Kennedy Center, Departments of Pediatrics, Pharmacology, and Special Education, Vanderbilt University Medical Center and Vanderbilt University, 1211 Medical Center Dr, Nashville, TN 37232, United States
| | - Katrina V Good
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College St, Toronto, ON M5T 1R8, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
| | - Kerry R Delaney
- Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
| | - Michael J Hendzel
- Departments of Oncology and Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Ave, Edmonton, AB T6G 2H7, Canada
| | - Zhaolan Zhou
- Department of Genetics, Epigenetics Institute, University of Pennsylvania Perelman School of Medicine, 3400 Civic Center Blvd, Philadelphia, PA 19104, United States
| | - Jeffrey L Neul
- Vanderbilt Kennedy Center, Departments of Pediatrics, Pharmacology, and Special Education, Vanderbilt University Medical Center and Vanderbilt University, 1211 Medical Center Dr, Nashville, TN 37232, United States
| | - John B Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College St, Toronto, ON M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, 27 King's College Cir, Toronto, ON M5S 1A8, Canada
- Department of Psychiatry, University of Toronto, 27 King College Cir, Toronto, ON M5T 1R8, Canada
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
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6
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Mayfield JM, Hitefield NL, Czajewski I, Vanhye L, Holden L, Morava E, van Aalten DMF, Wells L. O-GlcNAc transferase congenital disorder of glycosylation (OGT-CDG): Potential mechanistic targets revealed by evaluating the OGT interactome. J Biol Chem 2024; 300:107599. [PMID: 39059494 PMCID: PMC11381892 DOI: 10.1016/j.jbc.2024.107599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 07/10/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
O-GlcNAc transferase (OGT) is the sole enzyme responsible for the post-translational modification of O-GlcNAc on thousands of target nucleocytoplasmic proteins. To date, nine variants of OGT that segregate with OGT Congenital Disorder of Glycosylation (OGT-CDG) have been reported and characterized. Numerous additional variants have been associated with OGT-CDG, some of which are currently undergoing investigation. This disorder primarily presents with global developmental delay and intellectual disability (ID), alongside other variable neurological features and subtle facial dysmorphisms in patients. Several hypotheses aim to explain the etiology of OGT-CDG, with a prominent hypothesis attributing the pathophysiology of OGT-CDG to mutations segregating with this disorder disrupting the OGT interactome. The OGT interactome consists of thousands of proteins, including substrates as well as interactors that require noncatalytic functions of OGT. A key aim in the field is to identify which interactors and substrates contribute to the primarily neural-specific phenotype of OGT-CDG. In this review, we will discuss the heterogenous phenotypic features of OGT-CDG seen clinically, the variable biochemical effects of mutations associated with OGT-CDG, and the use of animal models to understand this disorder. Furthermore, we will discuss how previously identified OGT interactors causal for ID provide mechanistic targets for investigation that could explain the dysregulated gene expression seen in OGT-CDG models. Identifying shared or unique altered pathways impacted in OGT-CDG patients will provide a better understanding of the disorder as well as potential therapeutic targets.
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Affiliation(s)
- Johnathan M Mayfield
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Naomi L Hitefield
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | | | - Lotte Vanhye
- Department of Clinical Genomics and Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Laura Holden
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Eva Morava
- Department of Clinical Genomics and Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Daan M F van Aalten
- School of Life Sciences, University of Dundee, Dundee, UK; Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
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7
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Yu Y, Liu L, Cao J, Huang R, Duan Q, Ye SD. Tbl1 promotes Wnt-β-catenin signaling-induced degradation of the Tcf7l1 protein in mouse embryonic stem cells. J Cell Sci 2024; 137:jcs261241. [PMID: 38639717 DOI: 10.1242/jcs.261241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 04/08/2024] [Indexed: 04/20/2024] Open
Abstract
Activation of the Wnt-β-catenin signaling pathway by CHIR99021, a specific inhibitor of GSK3β, induces Tcf7l1 protein degradation, which facilitates the maintenance of an undifferentiated state in mouse embryonic stem cells (mESCs); however, the precise mechanism is still unclear. Here, we showed that the overexpression of transducin-β-like protein 1 (Tbl1, also known as Tbl1x) or its family member Tblr1 (also known as Tbl1xr1) can decrease Tcf7l1 protein levels, whereas knockdown of each gene increases Tcf7l1 levels without affecting Tcf7l1 transcription. Interestingly, only Tbl1, and not Tblr1, interacts with Tcf7l1. Mechanistically, Tbl1 translocates from the cytoplasm into the nucleus in association with β-catenin (CTNNB1) after the addition of CHIR99021 and functions as an adaptor to promote ubiquitylation of the Tcf7l1 protein. Functional assays further revealed that enforced expression of Tbl1 is capable of delaying mESC differentiation. In contrast, knockdown of Tbl1 attenuates the effect of CHIR99021 on Tcf7l1 protein stability and mESC self-renewal. Our results provide insight into the regulatory network of the Wnt-β-catenin signaling pathway involved in promoting the maintenance of naïve pluripotency.
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Affiliation(s)
- Yang Yu
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China
| | - Liwei Liu
- College of Medical Technology, Anhui Medical College, Hefei, Anhui, 230601, China
| | - Jianjian Cao
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China
| | - Ru Huang
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China
| | - Quanchao Duan
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China
| | - Shou-Dong Ye
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China
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Bijlani S, Pang KM, Bugga LV, Rangasamy S, Narayanan V, Chatterjee S. Nuclease-free precise genome editing corrects MECP2 mutations associated with Rett syndrome. Front Genome Ed 2024; 6:1346781. [PMID: 38495533 PMCID: PMC10940404 DOI: 10.3389/fgeed.2024.1346781] [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: 11/29/2023] [Accepted: 02/12/2024] [Indexed: 03/19/2024] Open
Abstract
Rett syndrome is an acquired progressive neurodevelopmental disorder caused by de novo mutations in the X-linked MECP2 gene which encodes a pleiotropic protein that functions as a global transcriptional regulator and a chromatin modifier. Rett syndrome predominantly affects heterozygous females while affected male hemizygotes rarely survive. Gene therapy of Rett syndrome has proven challenging due to a requirement for stringent regulation of expression with either over- or under-expression being toxic. Ectopic expression of MECP2 in conjunction with regulatory miRNA target sequences has achieved some success, but the durability of this approach remains unknown. Here we evaluated a nuclease-free homologous recombination (HR)-based genome editing strategy to correct mutations in the MECP2 gene. The stem cell-derived AAVHSCs have previously been shown to mediate seamless and precise HR-based genome editing. We tested the ability of HR-based genome editing to correct pathogenic mutations in Exons 3 and 4 of the MECP2 gene and restore the wild type sequence while preserving all native genomic regulatory elements associated with MECP2 expression, thus potentially addressing a significant issue in gene therapy for Rett syndrome. Moreover, since the mutations are edited directly at the level of the genome, the corrections are expected to be durable with progeny cells inheriting the edited gene. The AAVHSC MECP2 editing vector was designed to be fully homologous to the target MECP2 region and to insert a promoterless Venus reporter at the end of Exon 4. Evaluation of AAVHSC editing in a panel of Rett cell lines bearing mutations in Exons 3 and 4 demonstrated successful correction and rescue of expression of the edited MECP2 gene. Sequence analysis of edited Rett cells revealed successful and accurate correction of mutations in both Exons 3 and 4 and permitted mapping of HR crossover events. Successful correction was observed only when the mutations were flanked at both the 5' and 3' ends by crossover events, but not when both crossovers occurred either exclusively upstream or downstream of the mutation. Importantly, we concluded that pathogenic mutations were successfully corrected in every Rett line analyzed, demonstrating the therapeutic potential of HR-based genome editing.
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Affiliation(s)
- Swati Bijlani
- Department of Surgery, Beckman Research Institute of the City of Hope, Duarte, CA, United States
| | - Ka Ming Pang
- Department of Surgery, Beckman Research Institute of the City of Hope, Duarte, CA, United States
| | - Lakshmi V. Bugga
- Department of Surgery, Beckman Research Institute of the City of Hope, Duarte, CA, United States
| | - Sampath Rangasamy
- Center for Rare Childhood Disorders (C4RCD), Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ, United States
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders (C4RCD), Neurogenomics Division, Translational Genomics Research Institute (TGen), Phoenix, AZ, United States
| | - Saswati Chatterjee
- Department of Surgery, Beckman Research Institute of the City of Hope, Duarte, CA, United States
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9
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Nagy A, Molay F, Hargadon S, Brito Pires C, Grant N, De La Rosa Abreu L, Chen JY, D'Souza P, Macnamara E, Tifft C, Becker C, Melo De Gusmao C, Khurana V, Neumeyer AM, Eichler FS. The spectrum of neurological presentation in individuals affected by TBL1XR1 gene defects. Orphanet J Rare Dis 2024; 19:79. [PMID: 38378692 PMCID: PMC10880200 DOI: 10.1186/s13023-024-03083-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 02/09/2024] [Indexed: 02/22/2024] Open
Abstract
BACKGROUND TBL1XR1 encodes a F-box-like/WD40 repeat-containing protein that plays a role in transcription mediated by nuclear receptors and is a known genetic cause of neurodevelopmental disease of childhood (OMIM# 608628). Yet the developmental trajectory and progression of neurologic symptoms over time remains poorly understood. METHODS We developed and distributed a survey to two closed Facebook groups devoted to families of patients with TBL1XR1-related disorder. The survey consisted of 14 subsections focused upon the developmental trajectories of cognitive, behavioral, motor, and other neurological abnormalities. Data were collected and managed using REDCap electronic data capture tools. RESULTS Caregivers of 41 patients with a TBL1XR1-related disorder completed the cross-sectional survey. All reported variants affecting a single amino acid, including missense mutations and in-frame deletions, were found in the WD40 repeat regions of Tbl1xr1. These are domains considered important for protein-protein interactions that may plausibly underlie disease pathology. The majority of patients were diagnosed with a neurologic condition before they received their genetic diagnosis. Language appeared most significantly affected with only a minority of the cohort achieving more advanced milestones in this domain. CONCLUSION TBL1XR1-related disorder encompasses a spectrum of clinical presentations, marked by early developmental delay ranging in severity, with a subset of patients experiencing developmental regression in later childhood.
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Affiliation(s)
- Amanda Nagy
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA
| | - Francine Molay
- Division of Clinical Research, Massachusetts General Hospital, 55 Fruit St, Boston, MA, 02114, USA
| | - Sarah Hargadon
- Fly Little Bird Foundation, PO Box 698, Excelsior, MN, 55331, USA
| | - Claudia Brito Pires
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA
| | - Natalie Grant
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA
| | - Lizbeth De La Rosa Abreu
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA
| | - Jin Yun Chen
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA
| | - Precilla D'Souza
- National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Ellen Macnamara
- National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Cynthia Tifft
- National Human Genome Research Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Catherine Becker
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA
| | - Claudio Melo De Gusmao
- Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine Room 10016L, 60 Fenwood Road, Boston, 02115, USA
| | - Vikram Khurana
- Division of Movement Disorders, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine Room 10016L, 60 Fenwood Road, Boston, 02115, USA
| | - Ann M Neumeyer
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA
- Lurie Center for Autism, Massachusetts General Hospital, 1 Maguire Road, Lexington, MA, 02124, USA
| | - Florian S Eichler
- Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Wang Ambulatory Care Center 708, Boston, MA, 02114, USA.
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10
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Lopes AG, Loganathan SK, Caliaperumal J. Rett Syndrome and the Role of MECP2: Signaling to Clinical Trials. Brain Sci 2024; 14:120. [PMID: 38391695 PMCID: PMC10886956 DOI: 10.3390/brainsci14020120] [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: 12/14/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 02/24/2024] Open
Abstract
Rett syndrome (RTT) is a neurological disorder that mostly affects females, with a frequency of 1 in 10,000 to 20,000 live birth cases. Symptoms include stereotyped hand movements; impaired learning, language, and communication skills; sudden loss of speech; reduced lifespan; retarded growth; disturbance of sleep and breathing; seizures; autism; and gait apraxia. Pneumonia is the most common cause of death for patients with Rett syndrome, with a survival rate of 77.8% at 25 years of age. Survival into the fifth decade is typical in Rett syndrome, and the leading cause of death is cardiorespiratory compromise. Rett syndrome progression has multiple stages; however, most phenotypes are associated with the nervous system and brain. In total, 95% of Rett syndrome cases are due to mutations in the MECP2 gene, an X-linked gene that encodes for the methyl CpG binding protein, a regulator of gene expression. In this review, we summarize the recent developments in the field of Rett syndrome and therapeutics targeting MECP2.
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Affiliation(s)
- Adele Gaspar Lopes
- Department of Pharmacology, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 2M1, Canada
- Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Sampath Kumar Loganathan
- Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H4A 3J1, Canada
- Department of Otolaryngology, Head & Neck Surgery, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H4A 3J1, Canada
- Departments of Experimental Surgery and Experimental Medicine, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H4A 3J1, Canada
| | - Jayalakshmi Caliaperumal
- Ingram School of Nursing, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 2M7, Canada
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11
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Nettles SA, Ikeuchi Y, Lefton KB, Abbasi L, Erickson A, Agwu C, Papouin T, Bonni A, Gabel HW. MeCP2 represses the activity of topoisomerase IIβ in long neuronal genes. Cell Rep 2023; 42:113538. [PMID: 38096051 PMCID: PMC10844882 DOI: 10.1016/j.celrep.2023.113538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/31/2023] [Accepted: 11/20/2023] [Indexed: 12/30/2023] Open
Abstract
A unique signature of neurons is the high expression of the longest genes in the genome. These genes have essential neuronal functions, and disruption of their expression has been implicated in neurological disorders. DNA topoisomerases resolve DNA topological constraints and facilitate neuronal long gene expression. Conversely, the Rett syndrome protein, methyl-CpG-binding protein 2 (MeCP2), can transcriptionally repress long genes. How these factors regulate long genes is not well understood, and whether they interact is not known. Here, we identify and map a functional interaction between MeCP2 and topoisomerase IIβ (TOP2β) in mouse neurons. We profile neuronal TOP2β activity genome wide, detecting enrichment at regulatory regions and gene bodies of long genes, including MeCP2-regulated genes. We show that loss and overexpression of MeCP2 alter TOP2β activity at MeCP2-regulated genes. These findings uncover a mechanism of TOP2β inhibition by MeCP2 in neurons and implicate TOP2β dysregulation in disorders caused by MeCP2 disruption.
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Affiliation(s)
- Sabin A Nettles
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yoshiho Ikeuchi
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Katheryn B Lefton
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Ladan Abbasi
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alyssa Erickson
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Chibueze Agwu
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Thomas Papouin
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Azad Bonni
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Harrison W Gabel
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA.
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12
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Kalani L, Kim BH, Vincent JB, Ausió J. MeCP2 ubiquitination and sumoylation, in search of a function†. Hum Mol Genet 2023; 33:1-11. [PMID: 37694858 DOI: 10.1093/hmg/ddad150] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/12/2023] Open
Abstract
MeCP2 (Methyl CpG binding protein 2) is an intrinsically disordered protein that binds to methylated genome regions. The protein is a critical transcriptional regulator of the brain, and its mutations account for 95% of Rett syndrome (RTT) cases. Early studies of this neurodevelopmental disorder revealed a close connection with dysregulations of the ubiquitin system (UbS), notably as related to UBE3A, a ubiquitin ligase involved in the proteasome-mediated degradation of proteins. MeCP2 undergoes numerous post-translational modifications (PTMs), including ubiquitination and sumoylation, which, in addition to the potential functional outcomes of their monomeric forms in gene regulation and synaptic plasticity, in their polymeric organization, these modifications play a critical role in proteasomal degradation. UbS-mediated proteasomal degradation is crucial in maintaining MeCP2 homeostasis for proper function and is involved in decreasing MeCP2 in some RTT-causing mutations. However, regardless of all these connections to UbS, the molecular details involved in the signaling of MeCP2 for its targeting by the ubiquitin-proteasome system (UPS) and the functional roles of monomeric MeCP2 ubiquitination and sumoylation remain largely unexplored and are the focus of this review.
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Affiliation(s)
- Ladan Kalani
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
| | - Bo-Hyun Kim
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
| | - John B Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College St, Toronto, ON M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, 27 King's College Cir, Toronto, ON M5S 1A8, Canada
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 2Y2, Canada
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13
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Yang M, Zhou X, Pearce SW, Yang Z, Chen Q, Niu K, Liu C, Luo J, Li D, Shao Y, Zhang C, Chen D, Wu Q, Cutillas PR, Zhao L, Xiao Q, Zhang L. Causal Role for Neutrophil Elastase in Thoracic Aortic Dissection in Mice. Arterioscler Thromb Vasc Biol 2023; 43:1900-1920. [PMID: 37589142 PMCID: PMC10521802 DOI: 10.1161/atvbaha.123.319281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 08/01/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND Thoracic aortic dissection (TAD) is a life-threatening aortic disease without effective medical treatment. Increasing evidence has suggested a role for NE (neutrophil elastase) in vascular diseases. In this study, we aimed at investigating a causal role for NE in TAD and exploring the molecular mechanisms involved. METHODS β-aminopropionitrile monofumarate was administrated in mice to induce TAD. NE deficiency mice, pharmacological inhibitor GW311616A, and adeno-associated virus-2-mediated in vivo gene transfer were applied to explore a causal role for NE and associated target gene in TAD formation. Multiple functional assays and biochemical analyses were conducted to unravel the underlying cellular and molecular mechanisms of NE in TAD. RESULTS NE aortic gene expression and plasma activity was significantly increased during β-aminopropionitrile monofumarate-induced TAD and in patients with acute TAD. NE deficiency prevents β-aminopropionitrile monofumarate-induced TAD onset/development, and GW311616A administration ameliorated TAD formation/progression. Decreased levels of neutrophil extracellular traps, inflammatory cells, and MMP (matrix metalloproteinase)-2/9 were observed in NE-deficient mice. TBL1x (F-box-like/WD repeat-containing protein TBL1x) has been identified as a novel substrate and functional downstream target of NE in TAD. Loss-of-function studies revealed that NE mediated inflammatory cell transendothelial migration by modulating TBL1x-LTA4H (leukotriene A4 hydrolase) signaling and that NE regulated smooth muscle cell phenotype modulation under TAD pathological condition by regulating TBL1x-MECP2 (methyl CpG-binding protein 2) signal axis. Further mechanistic studies showed that TBL1x inhibition decreased the binding of TBL1x and HDAC3 (histone deacetylase 3) to MECP2 and LTA4H gene promoters, respectively. Finally, adeno-associated virus-2-mediated Tbl1x gene knockdown in aortic smooth muscle cells confirmed a regulatory role for TBL1x in NE-mediated TAD formation. CONCLUSIONS We unravel a critical role of NE and its target TBL1x in regulating inflammatory cell migration and smooth muscle cell phenotype modulation in the context of TAD. Our findings suggest that the NE-TBL1x signal axis represents a valuable therapeutic for treating high-risk TAD patients.
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Affiliation(s)
- Mei Yang
- Department of Cardiology, Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, China (M.Y., Q.C., D.L., L. Zhang)
- Faculty of Medicine and Dentistry, William Harvey Research Institute (M.Y., X.Z., S.W.A.P., Z.Y., K.N., C.L., Q.X.), Queen Mary University of London, United Kingdom
| | - Xinmiao Zhou
- Faculty of Medicine and Dentistry, William Harvey Research Institute (M.Y., X.Z., S.W.A.P., Z.Y., K.N., C.L., Q.X.), Queen Mary University of London, United Kingdom
- Department of Respiratory and Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China (X.Z.)
| | - Stuart W.A. Pearce
- Faculty of Medicine and Dentistry, William Harvey Research Institute (M.Y., X.Z., S.W.A.P., Z.Y., K.N., C.L., Q.X.), Queen Mary University of London, United Kingdom
| | - Zhisheng Yang
- Faculty of Medicine and Dentistry, William Harvey Research Institute (M.Y., X.Z., S.W.A.P., Z.Y., K.N., C.L., Q.X.), Queen Mary University of London, United Kingdom
| | - Qishan Chen
- Department of Cardiology, Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, China (M.Y., Q.C., D.L., L. Zhang)
| | - Kaiyuan Niu
- Faculty of Medicine and Dentistry, William Harvey Research Institute (M.Y., X.Z., S.W.A.P., Z.Y., K.N., C.L., Q.X.), Queen Mary University of London, United Kingdom
| | - Chenxin Liu
- Faculty of Medicine and Dentistry, William Harvey Research Institute (M.Y., X.Z., S.W.A.P., Z.Y., K.N., C.L., Q.X.), Queen Mary University of London, United Kingdom
| | - Jun Luo
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, China (J.L., Y.S., C.Z., D.C., Q.W.)
| | - Dan Li
- Department of Cardiology, Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, China (M.Y., Q.C., D.L., L. Zhang)
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, China (D.L., L. Zhao)
| | - Yue Shao
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, China (J.L., Y.S., C.Z., D.C., Q.W.)
| | - Cheng Zhang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, China (J.L., Y.S., C.Z., D.C., Q.W.)
| | - Dan Chen
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, China (J.L., Y.S., C.Z., D.C., Q.W.)
| | - Qingchen Wu
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical University, China (J.L., Y.S., C.Z., D.C., Q.W.)
| | - Pedro R. Cutillas
- Faculty of Medicine and Dentistry, Centre for Haemato-Oncology, Barts Cancer Institute (P.R.C.), Queen Mary University of London, United Kingdom
| | - Lin Zhao
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, China (D.L., L. Zhao)
| | - Qingzhong Xiao
- Faculty of Medicine and Dentistry, William Harvey Research Institute (M.Y., X.Z., S.W.A.P., Z.Y., K.N., C.L., Q.X.), Queen Mary University of London, United Kingdom
- Key Laboratory of Cardiovascular Diseases, School of Basic Medical Sciences, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, China (Q.X.)
| | - Li Zhang
- Department of Cardiology, Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, China (M.Y., Q.C., D.L., L. Zhang)
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14
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Mykins M, Layo-Carris D, Dunn LR, Skinner DW, McBryar AH, Perez S, Shultz TR, Willems A, Lau BYB, Hong T, Krishnan K. Wild-type MECP2 expression coincides with age-dependent sensory phenotypes in a female mouse model for Rett syndrome. J Neurosci Res 2023; 101:1236-1258. [PMID: 37026482 PMCID: PMC10332853 DOI: 10.1002/jnr.25190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/07/2023] [Accepted: 03/12/2023] [Indexed: 04/08/2023]
Abstract
Rett syndrome is characterized by an early period of typical development and then, regression of learned motor and speech skills in girls. Loss of MECP2 protein is thought to cause Rett syndrome phenotypes. The specific underlying mechanisms from typical developmental trajectory to regression features throughout life are unclear. Lack of established timelines to study the molecular, cellular, and behavioral features of regression in female mouse models is a major contributing factor. Due to random X-chromosome inactivation, female patients with Rett syndrome and female mouse models for Rett syndrome (Mecp2Heterozygous , Het) express a functional copy of wild-type MECP2 protein in approximately half of all cells. As MECP2 expression is regulated during early postnatal development and experience, we characterized the expression of wild-type MECP2 in the primary somatosensory cortex of female Het mice. Here, we report increased MECP2 levels in non-parvalbumin-positive neurons of 6-week-old adolescent Het relative to age-matched wild-type controls, while also displaying typical levels of perineuronal net expression in the barrel field subregion of the primary somatosensory cortex, mild tactile sensory perception deficits, and efficient pup retrieval behavior. In contrast, 12-week-old adult Het express MECP2 at levels similar to age-matched wild-type mice, show increased perineuronal net expression in the cortex, and display significant tactile sensory perception deficits. Thus, we have identified a set of behavioral metrics and the cellular substrates to study regression during a specific time in the female Het mouse model, which coincides with changes in wild-type MECP2 expression. We speculate that the precocious increase in MECP2 expression within specific cell types of adolescent Het may provide compensatory benefits at the behavioral level, while the inability to further increase MECP2 levels leads to regressive behavioral phenotypes over time.
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Affiliation(s)
- Michael Mykins
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Dana Layo-Carris
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Logan Reid Dunn
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - David Wilson Skinner
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Alexandra Hart McBryar
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Sarah Perez
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Trinity Rose Shultz
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Andrew Willems
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Billy You Bun Lau
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Tian Hong
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Keerthi Krishnan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
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15
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Chua GNL, Watters JW, Olinares PDB, Luo JA, Chait BT, Liu S. Differential dynamics specify MeCP2 function at methylated DNA and nucleosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543478. [PMID: 37333354 PMCID: PMC10274721 DOI: 10.1101/2023.06.02.543478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Methyl-CpG-binding protein 2 (MeCP2) is an essential chromatin-binding protein whose mutations cause Rett syndrome (RTT), a leading cause of monogenic intellectual disabilities in females. Despite its significant biomedical relevance, the mechanism by which MeCP2 navigates the chromatin epigenetic landscape to regulate chromatin structure and gene expression remains unclear. Here, we used correlative single-molecule fluorescence and force microscopy to directly visualize the distribution and dynamics of MeCP2 on a variety of DNA and chromatin substrates. We found that MeCP2 exhibits differential diffusion dynamics when bound to unmethylated and methylated bare DNA. Moreover, we discovered that MeCP2 preferentially binds nucleosomes within the context of chromatinized DNA and stabilizes them from mechanical perturbation. The distinct behaviors of MeCP2 at bare DNA and nucleosomes also specify its ability to recruit TBLR1, a core component of the NCoR1/2 co-repressor complex. We further examined several RTT mutations and found that they disrupt different aspects of the MeCP2-chromatin interaction, rationalizing the heterogeneous nature of the disease. Our work reveals the biophysical basis for MeCP2's methylation-dependent activities and suggests a nucleosome-centric model for its genomic distribution and gene repressive functions. These insights provide a framework for delineating the multifaceted functions of MeCP2 and aid in our understanding of the molecular mechanisms of RTT.
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Affiliation(s)
- Gabriella N. L. Chua
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional PhD Program in Chemical Biology, New York, NY, USA
| | - John W. Watters
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Joshua A. Luo
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Brian T. Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
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16
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Kim JW, Suzuki K, Kavalali ET, Monteggia LM. Bridging rapid and sustained antidepressant effects of ketamine. Trends Mol Med 2023; 29:364-375. [PMID: 36907686 PMCID: PMC10101916 DOI: 10.1016/j.molmed.2023.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/05/2023] [Accepted: 02/15/2023] [Indexed: 03/12/2023]
Abstract
Acute administration of (R,S)-ketamine (ketamine) produces rapid antidepressant effects that in some patients can be sustained for several days to more than a week. Ketamine blocks N-methyl-d-asparate (NMDA) receptors (NMDARs) to elicit specific downstream signaling that induces a novel form of synaptic plasticity in the hippocampus that has been linked to the rapid antidepressant action. These signaling events lead to subsequent downstream transcriptional changes that are involved in the sustained antidepressant effects. Here we review how ketamine triggers this intracellular signaling pathway to mediate synaptic plasticity which underlies the rapid antidepressant effects and links it to downstream signaling and the sustained antidepressant effects.
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Affiliation(s)
- Ji-Woon Kim
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA; College of Pharmacy, Kyung Hee University, Seoul, Republic of Korea; Department of Regulatory Science, Gradaute School, Kyung Hee University, Seoul, Republic of Korea; Institute of Regulatory Innovation through Science, Kyung Hee University, Seoul, Republic of Korea
| | - Kanzo Suzuki
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA; Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, Japan
| | - Ege T Kavalali
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA
| | - Lisa M Monteggia
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA.
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17
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Alexander-Howden B, Zhang L, van der Sloot AM, Tollis S, St-Cyr DJ, Sicheri F, Bird AP, Tyers M, Lyst MJ. A screen for MeCP2-TBL1 interaction inhibitors using a luminescence-based assay. Sci Rep 2023; 13:3868. [PMID: 36890145 PMCID: PMC9995496 DOI: 10.1038/s41598-023-29915-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/13/2023] [Indexed: 03/10/2023] Open
Abstract
Understanding the molecular pathology of neurodevelopmental disorders should aid the development of therapies for these conditions. In MeCP2 duplication syndrome (MDS)-a severe autism spectrum disorder-neuronal dysfunction is caused by increased levels of MeCP2. MeCP2 is a nuclear protein that binds to methylated DNA and recruits the nuclear co-repressor (NCoR) complex to chromatin via an interaction with the WD repeat-containing proteins TBL1 and TBLR1. The peptide motif in MeCP2 that binds to TBL1/TBLR1 is essential for the toxicity of excess MeCP2 in animal models of MDS, suggesting that small molecules capable of disrupting this interaction might be useful therapeutically. To facilitate the search for such compounds, we devised a simple and scalable NanoLuc luciferase complementation assay for measuring the interaction of MeCP2 with TBL1/TBLR1. The assay allowed excellent separation between positive and negative controls, and had low signal variance (Z-factor = 0.85). We interrogated compound libraries using this assay in combination with a counter-screen based on luciferase complementation by the two subunits of protein kinase A (PKA). Using this dual screening approach, we identified candidate inhibitors of the interaction between MeCP2 and TBL1/TBLR1. This work demonstrates the feasibility of future screens of large compound collections, which we anticipate will enable the development of small molecule therapeutics to ameliorate MDS.
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Affiliation(s)
- Beatrice Alexander-Howden
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Li Zhang
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Almer M van der Sloot
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
- Mila - Quebec Artificial Intelligence Institute, 6666 Rue Saint-Urbain, Montréal, QC, H2S 3H1, Canada
| | - Sylvain Tollis
- Institute of Biomedicine, University of Eastern Finland, 70210, Kuopio, Finland
| | - Daniel J St-Cyr
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
- X-Chem Inc, 7171 Frederick-Banting, Montréal, QC, H4S 1Z9, Canada
| | - Frank Sicheri
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, M5G 1X5, Canada
| | - Adrian P Bird
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF, UK.
| | - Mike Tyers
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, H3T 1J4, Canada.
- The Hospital for Sick Children Research Institute, Toronto, ON, M5G 0A4, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| | - Matthew J Lyst
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh, EH9 3BF, UK.
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18
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The TFIIS N-terminal domain (TND): a transcription assembly module at the interface of order and disorder. Biochem Soc Trans 2023; 51:125-135. [PMID: 36651856 PMCID: PMC9987994 DOI: 10.1042/bst20220342] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/19/2023]
Abstract
Interaction scaffolds that selectively recognize disordered protein strongly shape protein interactomes. An important scaffold of this type that contributes to transcription is the TFIIS N-terminal domain (TND). The TND is a five-helical bundle that has no known enzymatic activity, but instead selectively reads intrinsically disordered sequences of other proteins. Here, we review the structural and functional properties of TNDs and their cognate disordered ligands known as TND-interacting motifs (TIMs). TNDs or TIMs are found in prominent members of the transcription machinery, including TFIIS, super elongation complex, SWI/SNF, Mediator, IWS1, SPT6, PP1-PNUTS phosphatase, elongin, H3K36me3 readers, the transcription factor MYC, and others. We also review how the TND interactome contributes to the regulation of transcription. Because the TND is the most significantly enriched fold among transcription elongation regulators, TND- and TIM-driven interactions have widespread roles in the regulation of many transcriptional processes.
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19
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Zhang X, Cattoglio C, Zoltek M, Vetralla C, Mozumdar D, Schepartz A. Dose-Dependent Nuclear Delivery and Transcriptional Repression with a Cell-Penetrant MeCP2. ACS CENTRAL SCIENCE 2023; 9:277-288. [PMID: 36844491 PMCID: PMC9951310 DOI: 10.1021/acscentsci.2c01226] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Indexed: 06/13/2023]
Abstract
The vast majority of biologic-based therapeutics operate within serum, on the cell surface, or within endocytic vesicles, in large part because proteins and nucleic acids fail to efficiently cross cell or endosomal membranes. The impact of biologic-based therapeutics would expand exponentially if proteins and nucleic acids could reliably evade endosomal degradation, escape endosomal vesicles, and remain functional. Using the cell-permeant mini-protein ZF5.3, here we report the efficient nuclear delivery of functional Methyl-CpG-binding-protein 2 (MeCP2), a transcriptional regulator whose mutation causes Rett syndrome (RTT). We report that ZF-tMeCP2, a conjugate of ZF5.3 and MeCP2(Δaa13-71, 313-484), binds DNA in a methylation-dependent manner in vitro, and reaches the nucleus of model cell lines intact to achieve an average concentration of 700 nM. When delivered to live cells, ZF-tMeCP2 engages the NCoR/SMRT corepressor complex, selectively represses transcription from methylated promoters, and colocalizes with heterochromatin in mouse primary cortical neurons. We also report that efficient nuclear delivery of ZF-tMeCP2 relies on an endosomal escape portal provided by HOPS-dependent endosomal fusion. The Tat conjugate of MeCP2 (Tat-tMeCP2), evaluated for comparison, is degraded within the nucleus, is not selective for methylated promoters, and trafficks in a HOPS-independent manner. These results support the feasibility of a HOPS-dependent portal for delivering functional macromolecules to the cell interior using the cell-penetrant mini-protein ZF5.3. Such a strategy could broaden the impact of multiple families of biologic-based therapeutics.
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Affiliation(s)
- Xizi Zhang
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Claudia Cattoglio
- Department
of Molecular and Cellular Biology, University
of California, Berkeley, California 94720, United States
- Howard
Hughes Medical Institute, University of
California, Berkeley, California 94720, United States
| | - Madeline Zoltek
- Department
of Molecular and Cellular Biology, University
of California, Berkeley, California 94720, United States
| | - Carlo Vetralla
- Department
of Molecular and Cellular Biology, University
of California, Berkeley, California 94720, United States
- Howard
Hughes Medical Institute, University of
California, Berkeley, California 94720, United States
| | - Deepto Mozumdar
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Alanna Schepartz
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Department
of Molecular and Cellular Biology, University
of California, Berkeley, California 94720, United States
- California
Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, United States
- Chan Zuckerberg
Biohub, San Francisco, California 94158, United States
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20
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Klaus L, de Almeida BP, Vlasova A, Nemčko F, Schleiffer A, Bergauer K, Hofbauer L, Rath M, Stark A. Systematic identification and characterization of repressive domains in Drosophila transcription factors. EMBO J 2023; 42:e112100. [PMID: 36545802 PMCID: PMC9890238 DOI: 10.15252/embj.2022112100] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/21/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022] Open
Abstract
All multicellular life relies on differential gene expression, determined by regulatory DNA elements and DNA-binding transcription factors that mediate activation and repression via cofactor recruitment. While activators have been extensively characterized, repressors are less well studied: the identities and properties of their repressive domains (RDs) are typically unknown and the specific co-repressors (CoRs) they recruit have not been determined. Here, we develop a high-throughput, next-generation sequencing-based screening method, repressive-domain (RD)-seq, to systematically identify RDs in complex DNA-fragment libraries. Screening more than 200,000 fragments covering the coding sequences of all transcription-related proteins in Drosophila melanogaster, we identify 195 RDs in known repressors and in proteins not previously associated with repression. Many RDs contain recurrent short peptide motifs, which are conserved between fly and human and are required for RD function, as demonstrated by motif mutagenesis. Moreover, we show that RDs that contain one of five distinct repressive motifs interact with and depend on different CoRs, such as Groucho, CtBP, Sin3A, or Smrter. These findings advance our understanding of repressors, their sequences, and the functional impact of sequence-altering mutations and should provide a valuable resource for further studies.
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Affiliation(s)
- Loni Klaus
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD ProgramDoctoral School of the University of Vienna and Medical University of ViennaViennaAustria
| | - Bernardo P de Almeida
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD ProgramDoctoral School of the University of Vienna and Medical University of ViennaViennaAustria
| | - Anna Vlasova
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
| | - Filip Nemčko
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD ProgramDoctoral School of the University of Vienna and Medical University of ViennaViennaAustria
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
- Institute of Molecular Biotechnology (IMBA)Vienna BioCenter (VBC)ViennaAustria
| | - Katharina Bergauer
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
| | - Lorena Hofbauer
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
- Vienna BioCenter PhD ProgramDoctoral School of the University of Vienna and Medical University of ViennaViennaAustria
| | - Martina Rath
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP)Vienna BioCenter (VBC)ViennaAustria
- Medical University of ViennaVienna BioCenter (VBC)ViennaAustria
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21
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Cosma MA, Curtis NL, Pain C, Kriechbaumer V, Bolanos-Garcia VM. Biochemical, biophysical, and functional characterisation of the E3 ubiquitin ligase APC/C regulator CDC20 from Arabidopsis thaliana. Front Physiol 2022; 13:938688. [PMID: 35957989 PMCID: PMC9357983 DOI: 10.3389/fphys.2022.938688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 06/28/2022] [Indexed: 12/03/2022] Open
Abstract
The Anaphase Promoting Complex (APC/C), a large cullin-RING E3-type ubiquitin ligase, constitutes the ultimate target of the Spindle Assembly Checkpoint (SAC), an intricate regulatory circuit that ensures the high fidelity of chromosome segregation in eukaryotic organisms by delaying the onset of anaphase until each chromosome is properly bi-oriented on the mitotic spindle. Cell-division cycle protein 20 homologue (CDC20) is a key regulator of APC/C function in mitosis. The formation of the APC/CCDC20 complex is required for the ubiquitination and degradation of select substrates, which is necessary to maintain the mitotic state. In contrast to the roles of CDC20 in animal species, little is known about CDC20 roles in the regulation of chromosome segregation in plants. Here we address this gap in knowledge and report the expression in insect cells; the biochemical and biophysical characterisation of Arabidopsis thaliana (AtCDC20) WD40 domain; and the nuclear and cytoplasmic distribution of full-length AtCDC20 when transiently expressed in tobacco plants. We also show that most AtCDC20 degrons share a high sequence similarity to other eukaryotes, arguing in favour of conserved degron functions in AtCDC20. However, important exceptions were noted such as the lack of a canonical MAD1 binding motif; a fully conserved RRY-box in all six AtCDC20 isoforms instead of a CRY-box motif, and low conservation of key residues known to be phosphorylated by BUB1 and PLK1 in other species to ensure a robust SAC response. Taken together, our studies provide insights into AtCDC20 structure and function and the evolution of SAC signalling in plants.
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22
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Expression, Purification, Characterization and Cellular Uptake of MeCP2 Variants. Protein J 2022; 41:345-359. [PMID: 35546650 PMCID: PMC9122891 DOI: 10.1007/s10930-022-10054-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2022] [Indexed: 11/05/2022]
Abstract
The transcriptional regulator Methyl-CpG-binding protein 2 (MeCP2) is an intrinsically disordered protein, mutations in which, are implicated in the onset of Rett Syndrome, a severe and debilitating neurodevelopmental disorder. Delivery of this protein fused to the cell-penetrating peptide TAT could allow for the intracellular replenishment of functional MeCP2 and hence potentially serve as a prospective Rett Syndrome therapy. This work outlines the expression, purification and characterization of various TAT-MeCP2 constructs as well as their full-length and shortened eGFP fusion variants. The latter two constructs were used for intracellular uptake studies with subsequent analysis via western blotting and live-cell imaging. All purified MeCP2 samples exhibited high degree of stability and very little aggregation propensity. Full length and minimal TAT-MeCP2-eGFP were found to efficiently transduce into human dermal and murine fibroblasts and localize to cell nuclei. These findings clearly support the utility of MeCP2-based protein replacement therapy as a potential Rett Syndrome treatment option.
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23
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Steinkellner H, Kempaiah P, Beribisky AV, Pferschy S, Etzler J, Huber A, Sarne V, Neuhaus W, Kuttke M, Bauer J, Arunachalam JP, Christodoulou J, Dressel R, Mildner A, Prinz M, Laccone F. TAT-MeCP2 protein variants rescue disease phenotypes in human and mouse models of Rett syndrome. Int J Biol Macromol 2022; 209:972-983. [PMID: 35460749 DOI: 10.1016/j.ijbiomac.2022.04.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 01/02/2023]
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused by pathogenic variants leading to functional impairment of the MeCP2 protein. Here, we used purified recombinant MeCP2e1 and MeCP2e2 protein variants fused to a TAT protein transduction domain (PTD) to evaluate their transduction ability into RTT patient-derived fibroblasts and the ability to carry out their cellular function. We then assessed their transduction ability and therapeutic effects in a RTT mouse model. In vitro, TAT-MeCP2e2-eGFP reversed the pathological hyperacetylation of histones H3K9 and H4K16, a hallmark of abolition of MeCP2 function. In vivo, intraperitoneal administration of TAT-MeCP2e1 and TAT-MeCP2e2 extended the lifespan of Mecp2-/y mice by >50%. This was accompanied by rescue of hippocampal CA2 neuron size in animals treated with TAT-MeCP2e1. Taken together, these findings provide a strong indication that recombinant TAT-MeCP2 can reach mouse brains following peripheral injection and can ameliorate the phenotype of RTT mouse models. Thus, our study serves as a first step in the development of a potentially novel RTT therapy.
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Affiliation(s)
- Hannes Steinkellner
- Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Prakasha Kempaiah
- Institute for Human Genetics, Georg August University, Universitätsmedizin Göttingen, 37073 Göttingen, Germany; Division of Infectious Diseases, Mayo Clinic, Jacksonville, FL, USA
| | - Alexander V Beribisky
- Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Sandra Pferschy
- Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Julia Etzler
- Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Anna Huber
- Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, 1090 Vienna, Austria; Vienna Doctoral School of Pharmaceutical, Nutritional and Sport Sciences (PhaNuSpo), University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Victoria Sarne
- Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Winfried Neuhaus
- AIT Austrian Institute of Technology GmbH, Competence Center Molecular Diagnostics, 1210 Vienna, Austria
| | - Mario Kuttke
- Institute for Vascular Biology, Center for Physiology and Pharmacology, Medical University Vienna, Vienna, Austria
| | - Jan Bauer
- Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Jayamuruga P Arunachalam
- Institute for Human Genetics, Georg August University, Universitätsmedizin Göttingen, 37073 Göttingen, Germany; Division of Infectious Diseases, Mayo Clinic, Jacksonville, FL, USA; Department of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON, Canada
| | - John Christodoulou
- Murdoch Children's Research Institute and Department of Paediatrics, University of Melbourne, Discipline of Child & Adolescent Health, Sydney Medical School, Australia
| | - Ralf Dressel
- Department of Cellular and Molecular Immunology, Georg August University, Universitätsmedizin Göttingen, 37073 Göttingen, Germany
| | - Alexander Mildner
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany; Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany; Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Franco Laccone
- Center for Pathobiochemistry and Genetics, Institute of Medical Genetics, Medical University of Vienna, 1090 Vienna, Austria; Institute for Human Genetics, Georg August University, Universitätsmedizin Göttingen, 37073 Göttingen, Germany; Department of Cellular and Molecular Immunology, Georg August University, Universitätsmedizin Göttingen, 37073 Göttingen, Germany.
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24
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Krivdova G, Voisin V, Schoof EM, Marhon SA, Murison A, McLeod JL, Gabra MM, Zeng AGX, Aigner S, Yee BA, Shishkin AA, Van Nostrand EL, Hermans KG, Trotman-Grant AC, Mbong N, Kennedy JA, Gan OI, Wagenblast E, De Carvalho DD, Salmena L, Minden MD, Bader GD, Yeo GW, Dick JE, Lechman ER. Identification of the global miR-130a targetome reveals a role for TBL1XR1 in hematopoietic stem cell self-renewal and t(8;21) AML. Cell Rep 2022; 38:110481. [PMID: 35263585 PMCID: PMC11185845 DOI: 10.1016/j.celrep.2022.110481] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/03/2021] [Accepted: 02/11/2022] [Indexed: 11/18/2022] Open
Abstract
Gene expression profiling and proteome analysis of normal and malignant hematopoietic stem cells (HSCs) point to shared core stemness properties. However, discordance between mRNA and protein signatures highlights an important role for post-transcriptional regulation by microRNAs (miRNAs) in governing this critical nexus. Here, we identify miR-130a as a regulator of HSC self-renewal and differentiation. Enforced expression of miR-130a impairs B lymphoid differentiation and expands long-term HSCs. Integration of protein mass spectrometry and chimeric AGO2 crosslinking and immunoprecipitation (CLIP) identifies TBL1XR1 as a primary miR-130a target, whose loss of function phenocopies miR-130a overexpression. Moreover, we report that miR-130a is highly expressed in t(8;21) acute myeloid leukemia (AML), where it is critical for maintaining the oncogenic molecular program mediated by the AML1-ETO complex. Our study establishes that identification of the comprehensive miRNA targetome within primary cells enables discovery of genes and molecular networks underpinning stemness properties of normal and leukemic cells.
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Affiliation(s)
- Gabriela Krivdova
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A5, Canada
| | - Veronique Voisin
- The Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Erwin M Schoof
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Sajid A Marhon
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Alex Murison
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Jessica L McLeod
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Martino M Gabra
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Andy G X Zeng
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A5, Canada
| | - Stefan Aigner
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Brian A Yee
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Alexander A Shishkin
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Eric L Van Nostrand
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Karin G Hermans
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Program of Developmental & Stem Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON M5G0A4, Canada
| | - Aaron C Trotman-Grant
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Nathan Mbong
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - James A Kennedy
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Division of Medical Oncology and Hematology, Sunnybrook Health Sciences Centre, Toronto, ON M4N3M5, Canada
| | - Olga I Gan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Elvin Wagenblast
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Daniel D De Carvalho
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Leonardo Salmena
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Mark D Minden
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Gary D Bader
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A5, Canada; The Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5T 3A1, Canada
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - John E Dick
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S1A5, Canada.
| | - Eric R Lechman
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada.
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25
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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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26
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Pastore SF, Muhammad T, Harripaul R, Lau R, Khan MTM, Khan MI, Islam O, Kang C, Ayub M, Jelani M, Vincent JB. Biallelic inheritance in a single Pakistani family with intellectual disability implicates new candidate gene RDH14. Sci Rep 2021; 11:23113. [PMID: 34848785 PMCID: PMC8632963 DOI: 10.1038/s41598-021-02599-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 11/12/2021] [Indexed: 11/19/2022] Open
Abstract
In a multi-branch family from Pakistan, individuals presenting with palmoplantar keratoderma segregate in autosomal dominant fashion, and individuals with intellectual disability (ID) segregate in apparent autosomal recessive fashion. Initial attempts to identify the ID locus using homozygosity-by-descent (HBD) mapping were unsuccessful. However, following an assumption of locus heterogeneity, a reiterative HBD approach in concert with whole exome sequencing (WES) was employed. We identified a known disease-linked mutation in the polymicrogyria gene, ADGRG1, in two affected members. In the remaining two (living) affected members, HBD mapping cross-referenced with WES data identified a single biallelic frameshifting variant in the gene encoding retinol dehydrogenase 14 (RDH14). Transcription data indicate that RDH14 is expressed in brain, but not in retina. Magnetic resonance imaging for the individuals with this RDH14 mutation show no signs of polymicrogyria, however cerebellar atrophy was a notable feature. RDH14 in HEK293 cells localized mainly in the nucleoplasm. Co-immunoprecipitation studies confirmed binding to the proton-activated chloride channel 1 (PACC1/TMEM206), which is greatly diminished by the mutation. Our studies suggest RDH14 as a candidate for autosomal recessive ID and cerebellar atrophy, implicating either disrupted retinoic acid signaling, or, through PACC1, disrupted chloride ion homeostasis in the brain as a putative disease mechanism.
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Affiliation(s)
- Stephen F Pastore
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Tahir Muhammad
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Ricardo Harripaul
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Rebecca Lau
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Muhammad Tariq Masood Khan
- Department of Pathology, North-West School of Medicine, Hayatabad, Peshawar, Khyber Pakhtunkhwa, Pakistan
| | - Muhammad Ismail Khan
- Department of Zoology, Islamia College Peshawar, Peshawar, Khyber Pakhtunkhwa, Pakistan
| | - Omar Islam
- Department of Diagnostic Radiology, Queen's University, Kingston, ON, Canada
| | - Changsoo Kang
- Department of Biology and Institute of Basic Sciences, Sungshin Women's University, Seoul, Republic of Korea
| | - Muhammad Ayub
- Department of Psychiatry, Queen's University Kingston, Kingston, ON, Canada
| | - Musharraf Jelani
- Centre for Omic Sciences, Islamia College Peshawar, Peshawar, Khyber Pakhtunkhwa, Pakistan
| | - John B Vincent
- Molecular Neuropsychiatry and Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON, M5T 1R8, Canada.
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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27
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Pastore SF, Muhammad T, Harripaul R, Lau R, Khan MTM, Khan MI, Islam O, Kang C, Ayub M, Jelani M, Vincent JB. Biallelic inheritance in a single Pakistani family with intellectual disability implicates new candidate gene RDH14. Sci Rep 2021; 11:23113. [DOI: https:/doi.org/10.1038/s41598-021-02599-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 11/12/2021] [Indexed: 10/10/2023] Open
Abstract
AbstractIn a multi-branch family from Pakistan, individuals presenting with palmoplantar keratoderma segregate in autosomal dominant fashion, and individuals with intellectual disability (ID) segregate in apparent autosomal recessive fashion. Initial attempts to identify the ID locus using homozygosity-by-descent (HBD) mapping were unsuccessful. However, following an assumption of locus heterogeneity, a reiterative HBD approach in concert with whole exome sequencing (WES) was employed. We identified a known disease-linked mutation in the polymicrogyria gene, ADGRG1, in two affected members. In the remaining two (living) affected members, HBD mapping cross-referenced with WES data identified a single biallelic frameshifting variant in the gene encoding retinol dehydrogenase 14 (RDH14). Transcription data indicate that RDH14 is expressed in brain, but not in retina. Magnetic resonance imaging for the individuals with this RDH14 mutation show no signs of polymicrogyria, however cerebellar atrophy was a notable feature. RDH14 in HEK293 cells localized mainly in the nucleoplasm. Co-immunoprecipitation studies confirmed binding to the proton-activated chloride channel 1 (PACC1/TMEM206), which is greatly diminished by the mutation. Our studies suggest RDH14 as a candidate for autosomal recessive ID and cerebellar atrophy, implicating either disrupted retinoic acid signaling, or, through PACC1, disrupted chloride ion homeostasis in the brain as a putative disease mechanism.
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28
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Rosenberg A, Sibley LD. Toxoplasma gondii secreted effectors co-opt host repressor complexes to inhibit necroptosis. Cell Host Microbe 2021; 29:1186-1198.e8. [PMID: 34043960 PMCID: PMC8711274 DOI: 10.1016/j.chom.2021.04.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 02/22/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023]
Abstract
Toxoplasma gondii translocates effector proteins into its host cell to subvert various host pathways. T. gondii effector TgIST blocks the transcription of interferon-stimulated genes to reduce immune defense. Interferons upregulate numerous genes, including protein kinase R (PKR), which induce necrosome formation to activate mixed-lineage-kinase-domain-like (MLKL) pseudokinase and induce necroptosis. Whether these interferon functions are targeted by Toxoplasma is unknown. Here, we examine secreted effectors that localize to the host cell nucleus and find that the chronic bradyzoite stage secretes effector TgNSM that targets the NCoR/SMRT complex, a repressor for various transcription factors, to inhibit interferon-regulated genes involved in cell death. TgNSM acts with TgIST to block IFN-driven expression of PKR and MLKL, thus preventing host cell necroptotic death and protecting the parasite's intracellular niche. The mechanism of action of TgNSM uncovers a role of NCoR/SMRT in necroptosis, assuring survival of intracellular cysts and chronic infection.
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Affiliation(s)
- Alex Rosenberg
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63130, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63130, USA.
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29
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Vashi N, Ackerley C, Post M, Justice MJ. Aberrant lung lipids cause respiratory impairment in a Mecp2-deficient mouse model of Rett syndrome. Hum Mol Genet 2021; 30:2161-2176. [PMID: 34230964 PMCID: PMC8561422 DOI: 10.1093/hmg/ddab182] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/11/2021] [Accepted: 06/28/2021] [Indexed: 11/14/2022] Open
Abstract
Severe respiratory impairment is a prominent feature of Rett syndrome (RTT), an X-linked disorder caused by mutations in methyl CpG-binding protein 2 (MECP2). Despite MECP2's ubiquitous expression, respiratory anomalies are attributed to neuronal dysfunction. Here, we show that neutral lipids accumulate in mouse Mecp2-mutant lungs, while surfactant phospholipids decrease. Conditional deletion of Mecp2 from lipid-producing alveolar epithelial 2 (AE2) cells causes aberrant lung lipids and respiratory symptoms, while deletion of Mecp2 from hindbrain neurons results in distinct respiratory abnormalities. Single-cell RNA sequencing of AE2 cells suggests lipid production and storage increase at the expense of phospholipid synthesis. Lipid production enzymes are confirmed as direct targets of MECP2-directed nuclear receptor corepressor 1/2 (NCOR1/2) transcriptional repression. Remarkably, lipid-lowering fluvastatin improves respiratory anomalies in Mecp2-mutant mice. These data implicate autonomous pulmonary loss of MECP2 in respiratory symptoms for the first time and have immediate impacts on patient care.
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Affiliation(s)
- Neeti Vashi
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A1, Canada.,Genetics and Genome Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, M5G 0A4, Canada
| | - Cameron Ackerley
- Translational Medicine Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, M5G 0A4, Canada
| | - Martin Post
- Translational Medicine Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, M5G 0A4, Canada
| | - Monica J Justice
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A1, Canada.,Genetics and Genome Biology Program, Hospital for Sick Children, Peter Gilgan Centre for Research and Learning, Toronto, ON, M5G 0A4, Canada
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30
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Tillotson R, Cholewa-Waclaw J, Chhatbar K, Connelly JC, Kirschner SA, Webb S, Koerner MV, Selfridge J, Kelly DA, De Sousa D, Brown K, Lyst MJ, Kriaucionis S, Bird A. Neuronal non-CG methylation is an essential target for MeCP2 function. Mol Cell 2021; 81:1260-1275.e12. [PMID: 33561390 PMCID: PMC7980222 DOI: 10.1016/j.molcel.2021.01.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 11/17/2020] [Accepted: 01/07/2021] [Indexed: 02/07/2023]
Abstract
DNA methylation is implicated in neuronal biology via the protein MeCP2, the mutation of which causes Rett syndrome. MeCP2 recruits the NCOR1/2 co-repressor complexes to methylated cytosine in the CG dinucleotide, but also to sites of non-CG methylation, which are abundant in neurons. To test the biological significance of the dual-binding specificity of MeCP2, we replaced its DNA binding domain with an orthologous domain from MBD2, which can only bind mCG motifs. Knockin mice expressing the domain-swap protein displayed severe Rett-syndrome-like phenotypes, indicating that normal brain function requires the interaction of MeCP2 with sites of non-CG methylation, specifically mCAC. The results support the notion that the delayed onset of Rett syndrome is due to the simultaneous post-natal accumulation of mCAC and its reader MeCP2. Intriguingly, genes dysregulated in both Mecp2 null and domain-swap mice are implicated in other neurological disorders, potentially highlighting targets of relevance to the Rett syndrome phenotype.
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Affiliation(s)
- Rebekah Tillotson
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Justyna Cholewa-Waclaw
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Kashyap Chhatbar
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - John C Connelly
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Sophie A Kirschner
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Shaun Webb
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Martha V Koerner
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Jim Selfridge
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - David A Kelly
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Dina De Sousa
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Kyla Brown
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Matthew J Lyst
- Wellcome Centre for Cell Biology, University of Edinburgh, The Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Skirmantas Kriaucionis
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, 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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31
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Mastrototaro G, Zaghi M, Massimino L, Moneta M, Mohammadi N, Banfi F, Bellini E, Indrigo M, Fagnocchi G, Bagliani A, Taverna S, Rohm M, Herzig S, Sessa A. TBL1XR1 Ensures Balanced Neural Development Through NCOR Complex-Mediated Regulation of the MAPK Pathway. Front Cell Dev Biol 2021; 9:641410. [PMID: 33708771 PMCID: PMC7940385 DOI: 10.3389/fcell.2021.641410] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/04/2021] [Indexed: 12/19/2022] Open
Abstract
TBL1XR1 gene is associated with multiple developmental disorders presenting several neurological aspects. The relative protein is involved in the modulation of important cellular pathways and master regulators of transcriptional output, including nuclear receptor repressors, Wnt signaling, and MECP2 protein. However, TBL1XR1 mutations (including complete loss of its functions) have not been experimentally studied in a neurological context, leaving a knowledge gap in the mechanisms at the basis of the diseases. Here, we show that Tbl1xr1 knock-out mice exhibit behavioral and neuronal abnormalities. Either the absence of TBL1XR1 or its point mutations interfering with stability/regulation of NCOR complex induced decreased proliferation and increased differentiation in neural progenitors. We suggest that this developmental unbalance is due to a failure in the regulation of the MAPK cascade. Taken together, our results broaden the molecular and functional aftermath of TBL1XR1 deficiency associated with human disorders.
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Affiliation(s)
- Giuseppina Mastrototaro
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Mattia Zaghi
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Luca Massimino
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Matteo Moneta
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Neda Mohammadi
- Neurimmunology Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Federica Banfi
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Edoardo Bellini
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Marzia Indrigo
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Giulia Fagnocchi
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Anna Bagliani
- Medical Oncology Unit, ASST Ovest Milanese, Legnano Hospital, Legnano, Italy
| | - Stefano Taverna
- Neurimmunology Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria Rohm
- Institute for Diabetes and Cancer IDC, Helmholtz Center, Munich, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Medical Faculty, Technical University Munich, Munich, Germany.,German Center for Diabetes Research, Oberschleissheim, Germany
| | - Stephan Herzig
- Institute for Diabetes and Cancer IDC, Helmholtz Center, Munich, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Medical Faculty, Technical University Munich, Munich, Germany.,German Center for Diabetes Research, Oberschleissheim, Germany
| | - Alessandro Sessa
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
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32
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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: 61] [Impact Index Per Article: 20.3] [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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33
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Clemens AW, Gabel HW. Emerging Insights into the Distinctive Neuronal Methylome. Trends Genet 2020; 36:816-832. [PMID: 32839016 PMCID: PMC7572801 DOI: 10.1016/j.tig.2020.07.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 12/20/2022]
Abstract
The genomes of mammalian neurons are enriched for unique forms of DNA methylation, including exceptionally high levels of non-CG methylation. Here, we review recent studies defining how non-CG methylation accumulates in neurons and is read out by the critical regulator of neuronal transcription, MeCP2. We discuss the role of gene expression and genome architecture in establishing non-CG methylation and highlight emerging mechanistic insights into how non-CG methylation and MeCP2 control transcription. Further, we describe the cell type-specific functions of this methylation and explore growing evidence that disruption of this regulatory pathway contributes to neurodevelopmental disorders. These findings uncover how the distinctive epigenome in neurons facilitates the development and function of the complex mammalian brain.
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Affiliation(s)
- Adam W Clemens
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO 63110-1093, USA
| | - Harrison W Gabel
- Department of Neuroscience, Washington University School of Medicine, St Louis, MO 63110-1093, USA.
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34
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Nuclear receptor corepressors in intellectual disability and autism. Mol Psychiatry 2020; 25:2220-2236. [PMID: 32034290 PMCID: PMC7842082 DOI: 10.1038/s41380-020-0667-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 12/24/2019] [Accepted: 01/28/2020] [Indexed: 02/06/2023]
Abstract
Autism spectrum disorder (ASD) is characterized by neurocognitive dysfunctions, such as impaired social interaction and language learning. Gene-environment interactions have a pivotal role in ASD pathogenesis. Nuclear receptor corepressors (NCORs) are transcription co-regulators physically associated with histone deacetylases (HDACs) and many known players in ASD etiology such as transducin β-like 1 X-linked receptor 1 and methyl-CpG binding protein 2. The epigenome-modifying NCOR complex is sensitive to many ASD risk factors, including HDAC inhibitor valproic acid and a variety of endocrine factors, xenobiotic chemicals, or metabolites that can directly bind to multiple nuclear receptors. Here, we review recent studies of NCORs in neurocognition using animal models and human genetics approaches. We discuss functional interplays between NCORs and other known players in ASD etiology. It is conceivable that the NCOR complex may bridge the in utero environmental risk factors of ASD with epigenetic remodeling and can serve as a converging point for many gene-environment interactions in the pathogenesis of ASD and intellectual disability.
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35
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MeCP2 links heterochromatin condensates and neurodevelopmental disease. Nature 2020; 586:440-444. [PMID: 32698189 DOI: 10.1038/s41586-020-2574-4] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 07/15/2020] [Indexed: 12/15/2022]
Abstract
Methyl CpG binding protein 2 (MeCP2) is a key component of constitutive heterochromatin, which is crucial for chromosome maintenance and transcriptional silencing1-3. Mutations in the MECP2 gene cause the progressive neurodevelopmental disorder Rett syndrome3-5, which is associated with severe mental disability and autism-like symptoms that affect girls during early childhood. Although previously thought to be a dense and relatively static structure1,2, heterochromatin is now understood to exhibit properties consistent with a liquid-like condensate6,7. Here we show that MeCP2 is a dynamic component of heterochromatin condensates in cells, and is stimulated by DNA to form liquid-like condensates. MeCP2 contains several domains that contribute to the formation of condensates, and mutations in MECP2 that lead to Rett syndrome disrupt the ability of MeCP2 to form condensates. Condensates formed by MeCP2 selectively incorporate and concentrate heterochromatin cofactors rather than components of euchromatic transcriptionally active condensates. We propose that MeCP2 enhances the separation of heterochromatin and euchromatin through its condensate partitioning properties, and that disruption of condensates may be a common consequence of mutations in MeCP2 that cause Rett syndrome.
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36
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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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37
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Connelly JC, Cholewa-Waclaw J, Webb S, Steccanella V, Waclaw B, Bird A. Absence of MeCP2 binding to non-methylated GT-rich sequences in vivo. Nucleic Acids Res 2020; 48:3542-3552. [PMID: 32064528 PMCID: PMC7144902 DOI: 10.1093/nar/gkaa102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/18/2020] [Accepted: 02/13/2020] [Indexed: 12/16/2022] Open
Abstract
MeCP2 is a nuclear protein that binds to sites of cytosine methylation in the genome. While most evidence confirms this epigenetic mark as the primary determinant of DNA binding, MeCP2 is also reported to have an affinity for non-methylated DNA sequences. Here we investigated the molecular basis and in vivo significance of its reported affinity for non-methylated GT-rich sequences. We confirmed this interaction with isolated domains of MeCP2 in vitro and defined a minimal target DNA sequence. Binding depends on pyrimidine 5′ methyl groups provided by thymine and requires adjacent guanines and a correctly orientated A/T-rich flanking sequence. Unexpectedly, full-length MeCP2 protein failed to bind GT-rich sequences in vitro. To test for MeCP2 binding to these motifs in vivo, we analysed human neuronal cells using ChIP-seq and ATAC-seq technologies. While both methods robustly detected DNA methylation-dependent binding of MeCP2 to mCG and mCAC, neither showed evidence of MeCP2 binding to GT-rich motifs. The data suggest that GT binding is an in vitro phenomenon without in vivo relevance. Our findings argue that MeCP2 does not read unadorned DNA sequence and therefore support the notion that its primary role is to interpret epigenetic modifications of DNA.
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Affiliation(s)
- John C Connelly
- The Wellcome Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK
| | | | - Shaun Webb
- The Wellcome Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK
| | - Verdiana Steccanella
- The Wellcome Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK
| | - Bartlomiej Waclaw
- School of Physics and Astronomy, University of Edinburgh, EH9 3FD Edinburgh, UK
| | - Adrian Bird
- The Wellcome Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK
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38
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Understanding the Landscape of X-linked Variants Causing Intellectual Disability in Females Through Extreme X Chromosome Inactivation Skewing. Mol Neurobiol 2020; 57:3671-3684. [DOI: 10.1007/s12035-020-01981-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/08/2020] [Indexed: 12/14/2022]
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39
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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: 85] [Impact Index Per Article: 21.3] [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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40
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Iemolo A, Montilla-Perez P, Lai IC, Meng Y, Nolan S, Wen J, Rusu I, Dulcis D, Telese F. A cell type-specific expression map of NCoR1 and SMRT transcriptional co-repressors in the mouse brain. J Comp Neurol 2020; 528:2218-2238. [PMID: 32072640 DOI: 10.1002/cne.24886] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 12/12/2019] [Accepted: 02/12/2020] [Indexed: 12/11/2022]
Abstract
The ability to rapidly change gene expression patterns is essential for differentiation, development, and functioning of the brain. Throughout development, or in response to environmental stimuli, gene expression patterns are tightly regulated by the dynamic interplay between transcription activators and repressors. Nuclear receptor corepressor 1 (NCoR1) and silencing mediator for retinoid or thyroid-hormone receptors (SMRT) are the best characterized transcriptional co-repressors from a molecular point of view. They mediate epigenetic silencing of gene expression in a wide range of developmental and homeostatic processes in many tissues, including the brain. For instance, NCoR1 and SMRT regulate neuronal stem cell proliferation and differentiation during brain development and they have been implicated in learning and memory. However, we still have a limited understanding of their regional and cell type-specific expression in the brain. In this study, we used fluorescent immunohistochemistry to map their expression patterns throughout the adult mouse brain. Our findings reveal that NCoR1 and SMRT share an overall neuroanatomical distribution, and are detected in both excitatory and inhibitory neurons. However, we observed striking differences in their cell type-specific expression in glial cells. Specifically, all oligodendrocytes express NCoR1, but only a subset express SMRT. In addition, NCoR1, but not SMRT, was detected in a subset of astrocytes and in the microglia. These novel observations are corroborated by single cell transcriptomics and emphasize how NCoR1 and SMRT may contribute to distinct biological functions, suggesting an exclusive role of NCoR1 in innate immune responses in the brain.
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Affiliation(s)
- Attilio Iemolo
- Department of Medicine, University of California San Diego, La Jolla, California
| | | | - I-Chi Lai
- Department of Psychiatry, University of California San Diego, La Jolla, California
| | - Yinuo Meng
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Syreeta Nolan
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Junneng Wen
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Iulia Rusu
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Davide Dulcis
- Department of Psychiatry, University of California San Diego, La Jolla, California
| | - Francesca Telese
- Department of Medicine, University of California San Diego, La Jolla, California
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41
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Affinity for DNA Contributes to NLS Independent Nuclear Localization of MeCP2. Cell Rep 2020; 24:2213-2220. [PMID: 30157418 PMCID: PMC6130050 DOI: 10.1016/j.celrep.2018.07.099] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 06/22/2018] [Accepted: 07/26/2018] [Indexed: 12/14/2022] Open
Abstract
MeCP2 is a nuclear protein that is mutated in the severe neurological disorder Rett syndrome (RTT). The ability to target β-galactosidase to the nucleus was previously used to identify a conserved nuclear localization signal (NLS) in MeCP2 that interacts with the nuclear import factors KPNA3 and KPNA4. Here, we report that nuclear localization of MeCP2 does not depend on its NLS. Instead, our data reveal that an intact methyl-CpG binding domain (MBD) is sufficient for nuclear localization, suggesting that MeCP2 can be retained in the nucleus by its affinity for DNA. Consistent with these findings, we demonstrate that disease progression in a mouse model of RTT is unaffected by an inactivating mutation in the NLS of MeCP2. Taken together, our work reveals an unexpected redundancy between functional domains of MeCP2 in targeting this protein to the nucleus, potentially explaining why NLS-inactivating mutations are rarely associated with disease. Nuclear localization of MeCP2 does not require its NLS DNA binding by MeCP2 contributes to its NLS-independent nuclear localization MeCP2 NLS mutation does not affect pathology in a mouse model of Rett syndrome
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Lee EG, Tulloch J, Chen S, Leong L, Saxton AD, Kraemer B, Darvas M, Keene CD, Shutes-David A, Todd K, Millard S, Yu CE. Redefining transcriptional regulation of the APOE gene and its association with Alzheimer's disease. PLoS One 2020; 15:e0227667. [PMID: 31978088 PMCID: PMC6980611 DOI: 10.1371/journal.pone.0227667] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/24/2019] [Indexed: 01/09/2023] Open
Abstract
The apolipoprotein E gene (APOE) is the strongest genetic risk factor for late-onset Alzheimer's disease (AD), yet the expression of APOE is not clearly understood. For example, it is unclear whether AD patients have elevated or decreased APOE expression or why the correlation levels of APOE RNA and the ApoE protein differ across studies. Likewise, APOE has a single CpG island (CGI) that overlaps with its 3'-exon, and this CGI's effect is unknown. We previously reported that the APOE CGI is highly methylated in human postmortem brain (PMB) and that this methylation is altered in AD frontal lobe. In this study, we comprehensively characterized APOE RNA transcripts and correlated levels of RNA expression with DNA methylation levels across the APOE CGI. We discovered the presence of APOE circular RNA (circRNA) and found that circRNA and full-length mRNA each constitute approximately one third of the total APOE RNA, with truncated mRNAs likely constituting some of the missing fraction. All APOE RNA species demonstrated significantly higher expression in AD frontal lobe than in control frontal lobe. Furthermore, we observed a negative correlation between the levels of total APOE RNA and DNA methylation at the APOE CGI in the frontal lobe. When stratified by disease status, this correlation was strengthened in controls but not in AD. Our findings suggest a possible modified mechanism of gene action for APOE in AD that involves not only the protein isoforms but also an epigenetically regulated transcriptional program driven by DNA methylation in the APOE CGI.
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Affiliation(s)
- Eun-Gyung Lee
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Jessica Tulloch
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Sunny Chen
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Lesley Leong
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Aleen D. Saxton
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Brian Kraemer
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
- Department of Medicine, University of Washington, Seattle, WA, United States of America
| | - Martin Darvas
- Department of Pathology, University of Washington, Seattle, WA, United States of America
| | - C. Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA, United States of America
| | - Andrew Shutes-David
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Kaitlin Todd
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Steve Millard
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Chang-En Yu
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
- Department of Medicine, University of Washington, Seattle, WA, United States of America
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Piccolo FM, Liu Z, Dong P, Hsu CL, Stoyanova EI, Rao A, Tjian R, Heintz N. MeCP2 nuclear dynamics in live neurons results from low and high affinity chromatin interactions. eLife 2019; 8:51449. [PMID: 31868585 PMCID: PMC6957317 DOI: 10.7554/elife.51449] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/22/2019] [Indexed: 01/08/2023] Open
Abstract
Methyl-CpG-binding-Protein 2 (MeCP2) is an abundant nuclear protein highly enriched in neurons. Here we report live-cell single-molecule imaging studies of the kinetic features of mouse MeCP2 at high spatial-temporal resolution. MeCP2 displays dynamic features that are distinct from both highly mobile transcription factors and immobile histones. Stable binding of MeCP2 in living neurons requires its methyl-binding domain and is sensitive to DNA modification levels. Diffusion of unbound MeCP2 is strongly constrained by weak, transient interactions mediated primarily by its AT-hook domains, and varies with the level of chromatin compaction and cell type. These findings extend previous studies of the role of the MeCP2 MBD in high affinity DNA binding to living neurons, and identify a new role for its AT-hooks domains as critical determinants of its kinetic behavior. They suggest that limited nuclear diffusion of MeCP2 in live neurons contributes to its local impact on chromatin structure and gene expression.
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Affiliation(s)
- Francesco M Piccolo
- Laboratory of Molecular Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Zhe Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Peng Dong
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Ching-Lung Hsu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Elitsa I Stoyanova
- Laboratory of Molecular Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Anjana Rao
- La Jolla Institute for Allergy and Immunology, La Jolla, United States
| | - Robert Tjian
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Howard Hughes Medical Institute, Berkeley, United States
| | - Nathaniel Heintz
- Laboratory of Molecular Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
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Lavery LA, Zoghbi HY. The distinct methylation landscape of maturing neurons and its role in Rett syndrome pathogenesis. Curr Opin Neurobiol 2019; 59:180-188. [PMID: 31542590 PMCID: PMC6892602 DOI: 10.1016/j.conb.2019.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/21/2019] [Indexed: 02/06/2023]
Abstract
Rett syndrome (RTT) is one of the most common causes of intellectual and developmental disabilities in girls, and is caused by mutations in the gene encoding methyl-CpG binding protein 2 (MECP2). Here we will review our current understanding of RTT, the landscape of pathogenic mutations and function of MeCP2, and culminate with recent advances elucidating the distinct DNA methylation landscape in the brain that may explain why disease symptoms are delayed and selective to the nervous system.
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Affiliation(s)
- Laura A Lavery
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Huda Y Zoghbi
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
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Boxer LD, Renthal W, Greben AW, Whitwam T, Silberfeld A, Stroud H, Li E, Yang MG, Kinde B, Griffith EC, Bonev B, Greenberg ME. MeCP2 Represses the Rate of Transcriptional Initiation of Highly Methylated Long Genes. Mol Cell 2019; 77:294-309.e9. [PMID: 31784358 DOI: 10.1016/j.molcel.2019.10.032] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 09/09/2019] [Accepted: 10/23/2019] [Indexed: 12/14/2022]
Abstract
Mutations in the methyl-DNA-binding repressor protein MeCP2 cause the devastating neurodevelopmental disorder Rett syndrome. It has been challenging to understand how MeCP2 regulates transcription because MeCP2 binds broadly across the genome and MeCP2 mutations are associated with widespread small-magnitude changes in neuronal gene expression. We demonstrate here that MeCP2 represses nascent RNA transcription of highly methylated long genes in the brain through its interaction with the NCoR co-repressor complex. By measuring the rates of transcriptional initiation and elongation directly in the brain, we find that MeCP2 has no measurable effect on transcriptional elongation, but instead represses the rate at which Pol II initiates transcription of highly methylated long genes. These findings suggest a new model of MeCP2 function in which MeCP2 binds broadly across highly methylated regions of DNA, but acts at transcription start sites to attenuate transcriptional initiation.
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Affiliation(s)
- Lisa D Boxer
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - William Renthal
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Alexander W Greben
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Tess Whitwam
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Andrew Silberfeld
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Hume Stroud
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Emmy Li
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Marty G Yang
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Benyam Kinde
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Eric C Griffith
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Boyan Bonev
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Michael E Greenberg
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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MeCP2-E1 isoform is a dynamically expressed, weakly DNA-bound protein with different protein and DNA interactions compared to MeCP2-E2. Epigenetics Chromatin 2019; 12:63. [PMID: 31601272 PMCID: PMC6786283 DOI: 10.1186/s13072-019-0298-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 08/22/2019] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND MeCP2-a chromatin-binding protein associated with Rett syndrome-has two main isoforms, MeCP2-E1 and MeCP2-E2, differing in a few N-terminal amino acid residues. Previous studies have shown brain region-specific expression of these isoforms which, in addition to their different cellular localization and differential expression during brain development, suggest that they may also have non-overlapping molecular mechanisms. However, differential functions of MeCP2-E1 and E2 remain largely unexplored. RESULTS Here, we show that the N-terminal domains (NTD) of MeCP2-E1 and E2 modulate the ability of the methyl-binding domain (MBD) to interact with DNA as well as influencing the turn-over rates, binding dynamics, response to neuronal depolarization, and circadian oscillations of the two isoforms. Our proteomics data indicate that both isoforms exhibit unique interacting protein partners. Moreover, genome-wide analysis using ChIP-seq provide evidence for a shared as well as a specific regulation of different sets of genes. CONCLUSIONS Our study supports the idea that Rett syndrome might arise from simultaneous impairment of cellular processes involving non-overlapping functions of MECP2 isoforms. For instance, MeCP2-E1 mutations might impact stimuli-dependent chromatin regulation, while MeCP2-E2 mutations could result in aberrant ribosomal expression. Overall, our findings provide insight into the functional complexity of MeCP2 by dissecting differential aspects of its two isoforms.
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Li L, Jin J, Yang XJ. Histone Deacetylase 3 Governs Perinatal Cerebral Development via Neural Stem and Progenitor Cells. iScience 2019; 20:148-167. [PMID: 31569049 PMCID: PMC6823663 DOI: 10.1016/j.isci.2019.09.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 08/01/2019] [Accepted: 09/11/2019] [Indexed: 12/13/2022] Open
Abstract
We report that cerebrum-specific inactivation of the histone deacetylase 3 (HDAC3) gene causes striking developmental defects in the neocortex, hippocampus, and corpus callosum; post-weaning lethality; and abnormal behaviors, including hyperactivity and anxiety. The defects are due to rapid loss of embryonic neural stem and progenitor cells (NSPCs). Premature neurogenesis and abnormal neuronal migration in the mutant brain alter NSPC homeostasis. Mutant cerebral cortices also display augmented DNA damage responses, apoptosis, and histone hyperacetylation. Moreover, mutant NSPCs are impaired in forming neurospheres in vitro, and treatment with the HDAC3-specific inhibitor RGFP966 abolishes neurosphere formation. Transcriptomic analyses of neonatal cerebral cortices and cultured neurospheres support that HDAC3 regulates transcriptional programs through interaction with different transcription factors, including NFIB. These findings establish HDAC3 as a major deacetylase critical for perinatal development of the mouse cerebrum and NSPCs, thereby suggesting a direct link of this enzymatic epigenetic regulator to human cerebral and intellectual development. HDAC3 inactivation causes developmental defects in the neocortex and hippocampus HDAC3 loss leads to depletion of embryonic neural stem and progenitor cells HDAC3 inhibition abolishes neurosphere formation in vitro HDAC3 interacts with NFIB and other transcription factors in cerebral development
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Affiliation(s)
- Lin Li
- The Rosalind & Morris Goodman Cancer Research Center, Montreal, QC H3A 1A3, Canada; Department of Medicine and McGill University, Montreal, QC H3A 1A3, Canada
| | - Jianliang Jin
- The Rosalind & Morris Goodman Cancer Research Center, Montreal, QC H3A 1A3, Canada; Research Center for Bone and Stem Cells, Department of Human Anatomy, Key Laboratory of Aging & Disease, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Xiang-Jiao Yang
- The Rosalind & Morris Goodman Cancer Research Center, Montreal, QC H3A 1A3, Canada; Department of Medicine and McGill University, Montreal, QC H3A 1A3, Canada; Department of Biochemistry, McGill University, Montreal, QC H3A 1A3, Canada; Department of Medicine, McGill University Health Center, Montreal, QC H3A 1A3, Canada.
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Abstract
Rett syndrome (RTT) is a severe neurological disorder caused by mutations in the gene encoding methyl-CpG-binding protein 2 (MeCP2). Almost two decades of research into RTT have greatly advanced our understanding of the function and regulation of the multifunctional protein MeCP2. Here, we review recent advances in understanding how loss of MeCP2 impacts different stages of brain development, discuss recent findings demonstrating the molecular role of MeCP2 as a transcriptional repressor, assess primary and secondary effects of MeCP2 loss and examine how loss of MeCP2 can result in an imbalance of neuronal excitation and inhibition at the circuit level along with dysregulation of activity-dependent mechanisms. These factors present challenges to the search for mechanism-based therapeutics for RTT and suggest specific approaches that may be more effective than others.
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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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Keidar L, Gerlitz G, Kshirsagar A, Tsoory M, Olender T, Wang X, Yang Y, Chen YS, Yang YG, Voineagu I, Reiner O. Interplay of LIS1 and MeCP2: Interactions and Implications With the Neurodevelopmental Disorders Lissencephaly and Rett Syndrome. Front Cell Neurosci 2019; 13:370. [PMID: 31474834 PMCID: PMC6703185 DOI: 10.3389/fncel.2019.00370] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 07/30/2019] [Indexed: 12/30/2022] Open
Abstract
LIS1 is the main causative gene for lissencephaly, while MeCP2 is the main causative gene for Rett syndrome, both of which are neurodevelopmental diseases. Here we report nuclear functions for LIS1 and identify previously unrecognized physical and genetic interactions between the products of these two genes in the cell nucleus, that has implications on MeCP2 organization, neuronal gene expression and mouse behavior. Reduced LIS1 levels affect the association of MeCP2 with chromatin. Transcriptome analysis of primary cortical neurons derived from wild type, Lis1±, MeCP2−/y, or double mutants mice revealed a large overlap in the differentially expressed (DE) genes between the various mutants. Overall, our findings provide insights on molecular mechanisms involved in the neurodevelopmental disorders lissencephaly and Rett syndrome caused by dysfunction of LIS1 and MeCP2, respectively.
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Affiliation(s)
- Liraz Keidar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Gabi Gerlitz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Aditya Kshirsagar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Tsoory
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Tsviya Olender
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Xing Wang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Ying Yang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Yu-Sheng Chen
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Yun-Gui Yang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Irina Voineagu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Orly Reiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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