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Mfarej MG, Hyland CA, Sanchez AC, Falk MM, Iovine MK, Skibbens RV. Cohesin: an emerging master regulator at the heart of cardiac development. Mol Biol Cell 2023; 34:rs2. [PMID: 36947206 PMCID: PMC10162415 DOI: 10.1091/mbc.e22-12-0557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/10/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023] Open
Abstract
Cohesins are ATPase complexes that play central roles in cellular processes such as chromosome division, DNA repair, and gene expression. Cohesinopathies arise from mutations in cohesin proteins or cohesin complex regulators and encompass a family of related developmental disorders that present with a range of severe birth defects, affect many different physiological systems, and often lead to embryonic fatality. Treatments for cohesinopathies are limited, in large part due to the lack of understanding of cohesin biology. Thus, characterizing the signaling networks that lie upstream and downstream of cohesin-dependent pathways remains clinically relevant. Here, we highlight alterations in cohesins and cohesin regulators that result in cohesinopathies, with a focus on cardiac defects. In addition, we suggest a novel and more unifying view regarding the mechanisms through which cohesinopathy-based heart defects may arise.
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Affiliation(s)
- Michael G. Mfarej
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Caitlin A. Hyland
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Annie C. Sanchez
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Matthias M. Falk
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - M. Kathryn Iovine
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
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Mfarej MG, Skibbens RV. Genetically induced redox stress occurs in a yeast model for Roberts syndrome. G3 (BETHESDA, MD.) 2022; 12:6460337. [PMID: 34897432 PMCID: PMC9210317 DOI: 10.1093/g3journal/jkab426] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/01/2021] [Indexed: 12/31/2022]
Abstract
Roberts syndrome (RBS) is a multispectrum developmental disorder characterized by severe limb, craniofacial, and organ abnormalities and often intellectual disabilities. The genetic basis of RBS is rooted in loss-of-function mutations in the essential N-acetyltransferase ESCO2 which is conserved from yeast (Eco1/Ctf7) to humans. ESCO2/Eco1 regulate many cellular processes that impact chromatin structure, chromosome transmission, gene expression, and repair of the genome. The etiology of RBS remains contentious with current models that include transcriptional dysregulation or mitotic failure. Here, we report evidence that supports an emerging model rooted in defective DNA damage responses. First, the results reveal that redox stress is elevated in both eco1 and cohesion factor Saccharomyces cerevisiae mutant cells. Second, we provide evidence that Eco1 and cohesion factors are required for the repair of oxidative DNA damage such that ECO1 and cohesin gene mutations result in reduced cell viability and hyperactivation of DNA damage checkpoints that occur in response to oxidative stress. Moreover, we show that mutation of ECO1 is solely sufficient to induce endogenous redox stress and sensitizes mutant cells to exogenous genotoxic challenges. Remarkably, antioxidant treatment desensitizes eco1 mutant cells to a range of DNA damaging agents, raising the possibility that modulating the cellular redox state may represent an important avenue of treatment for RBS and tumors that bear ESCO2 mutations.
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Affiliation(s)
- Michael G Mfarej
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
| | - Robert V Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015, USA
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3
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Skupien-Jaroszek A, Walczak A, Czaban I, Pels KK, Szczepankiewicz AA, Krawczyk K, Ruszczycki B, Wilczynski GM, Dzwonek J, Magalska A. The interplay of seizures-induced axonal sprouting and transcription-dependent Bdnf repositioning in the model of temporal lobe epilepsy. PLoS One 2021; 16:e0239111. [PMID: 34086671 PMCID: PMC8177504 DOI: 10.1371/journal.pone.0239111] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 05/17/2021] [Indexed: 01/19/2023] Open
Abstract
The Brain-Derived Neurotrophic Factor is one of the most important trophic proteins in the brain. The role of this growth factor in neuronal plasticity, in health and disease, has been extensively studied. However, mechanisms of epigenetic regulation of Bdnf gene expression in epilepsy are still elusive. In our previous work, using a rat model of neuronal activation upon kainate-induced seizures, we observed a repositioning of Bdnf alleles from the nuclear periphery towards the nuclear center. This change of Bdnf intranuclear position was associated with transcriptional gene activity. In the present study, using the same neuronal activation model, we analyzed the relation between the percentage of the Bdnf allele at the nuclear periphery and clinical and morphological traits of epilepsy. We observed that the decrease of the percentage of the Bdnf allele at the nuclear periphery correlates with stronger mossy fiber sprouting-an aberrant form of excitatory circuits formation. Moreover, using in vitro hippocampal cultures we showed that Bdnf repositioning is a consequence of transcriptional activity. Inhibition of RNA polymerase II activity in primary cultured neurons with Actinomycin D completely blocked Bdnf gene transcription and repositioning occurring after neuronal excitation. Interestingly, we observed that histone deacetylases inhibition with Trichostatin A induced a slight increase of Bdnf gene transcription and its repositioning even in the absence of neuronal excitation. Presented results provide novel insight into the role of BDNF in epileptogenesis. Moreover, they strengthen the statement that this particular gene is a good candidate to search for a new generation of antiepileptic therapies.
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Affiliation(s)
- Anna Skupien-Jaroszek
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Walczak
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Iwona Czaban
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Karolina Pels
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Andrzej Antoni Szczepankiewicz
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Krawczyk
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Błażej Ruszczycki
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Grzegorz Marek Wilczynski
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Joanna Dzwonek
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- * E-mail: (AM); (JD)
| | - Adriana Magalska
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- * E-mail: (AM); (JD)
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Mfarej MG, Skibbens RV. An ever-changing landscape in Roberts syndrome biology: Implications for macromolecular damage. PLoS Genet 2020; 16:e1009219. [PMID: 33382686 PMCID: PMC7774850 DOI: 10.1371/journal.pgen.1009219] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Roberts syndrome (RBS) is a rare developmental disorder that can include craniofacial abnormalities, limb malformations, missing digits, intellectual disabilities, stillbirth, and early mortality. The genetic basis for RBS is linked to autosomal recessive loss-of-function mutation of the establishment of cohesion (ESCO) 2 acetyltransferase. ESCO2 is an essential gene that targets the DNA-binding cohesin complex. ESCO2 acetylates alternate subunits of cohesin to orchestrate vital cellular processes that include sister chromatid cohesion, chromosome condensation, transcription, and DNA repair. Although significant advances were made over the last 20 years in our understanding of ESCO2 and cohesin biology, the molecular etiology of RBS remains ambiguous. In this review, we highlight current models of RBS and reflect on data that suggests a novel role for macromolecular damage in the molecular etiology of RBS.
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Affiliation(s)
- Michael G. Mfarej
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
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Cheng H, Zhang N, Pati D. Cohesin subunit RAD21: From biology to disease. Gene 2020; 758:144966. [PMID: 32687945 PMCID: PMC7949736 DOI: 10.1016/j.gene.2020.144966] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023]
Abstract
RAD21 (also known as KIAA0078, NXP1, HR21, Mcd1, Scc1, and hereafter called RAD21), an essential gene, encodes a DNA double-strand break (DSB) repair protein that is evolutionarily conserved in all eukaryotes from budding yeast to humans. RAD21 protein is a structural component of the highly conserved cohesin complex consisting of RAD21, SMC1a, SMC3, and SCC3 [STAG1 (SA1) and STAG2 (SA2) in metazoans] proteins, involved in sister chromatid cohesion. This function is essential for proper chromosome segregation, post-replicative DNA repair, and prevention of inappropriate recombination between repetitive regions. In interphase, cohesin also functions in the control of gene expression by binding to numerous sites within the genome. In addition to playing roles in the normal cell cycle and DNA DSB repair, RAD21 is also linked to the apoptotic pathways. Germline heterozygous or homozygous missense mutations in RAD21 have been associated with human genetic disorders, including developmental diseases such as Cornelia de Lange syndrome (CdLS) and chronic intestinal pseudo-obstruction (CIPO) called Mungan syndrome, respectively, and collectively termed as cohesinopathies. Somatic mutations and amplification of the RAD21 have also been widely reported in both human solid and hematopoietic tumors. Considering the role of RAD21 in a broad range of cellular processes that are hot spots in neoplasm, it is not surprising that the deregulation of RAD21 has been increasingly evident in human cancers. Herein, we review the biology of RAD21 and the cellular processes that this important protein regulates and discuss the significance of RAD21 deregulation in cancer and cohesinopathies.
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Affiliation(s)
- Haizi Cheng
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Nenggang Zhang
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Debananda Pati
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States.
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Bettini LR, Graziola F, Fazio G, Grazioli P, Scagliotti V, Pasquini M, Cazzaniga G, Biondi A, Larizza L, Selicorni A, Gaston-Massuet C, Massa V. Rings and Bricks: Expression of Cohesin Components is Dynamic during Development and Adult Life. Int J Mol Sci 2018; 19:E438. [PMID: 29389897 PMCID: PMC5855660 DOI: 10.3390/ijms19020438] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 01/26/2018] [Accepted: 01/28/2018] [Indexed: 02/07/2023] Open
Abstract
Cohesin complex components exert fundamental roles in animal cells, both canonical in cell cycle and non-canonical in gene expression regulation. Germline mutations in genes coding for cohesins result in developmental disorders named cohesinopaties, of which Cornelia de Lange syndrome (CdLS) is the best-known entity. However, a basic description of mammalian expression pattern of cohesins in a physiologic condition is still needed. Hence, we report a detailed analysis of expression in murine and human tissues of cohesin genes defective in CdLS. Using both quantitative and qualitative methods in fetal and adult tissues, cohesin genes were found to be ubiquitously and differentially expressed in human tissues. In particular, abundant expression was observed in hematopoietic and central nervous system organs. Findings of the present study indicate tissues which should be particularly sensitive to mutations, germline and/or somatic, in cohesin genes. Hence, this expression analysis in physiological conditions may represent a first core reference for cohesinopathies.
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Affiliation(s)
- Laura Rachele Bettini
- Dipartimento di Scienze Della Salute, San Paolo Hospital Medical School, Università degli Studi di Milano, 20142 Milan, Italy.
- Clinica Pediatrica, Dipartimento di Medicina e Chirurgia, Università di Milano-Bicocca Ospedale San Gerardo/Fondazione MBBM, 20900 Monza, Italy.
| | - Federica Graziola
- Dipartimento di Scienze Della Salute, San Paolo Hospital Medical School, Università degli Studi di Milano, 20142 Milan, Italy.
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
| | - Grazia Fazio
- Centro Ricerca M. Tettamanti, Clinica Pediatrica, Dipartimento di Medicina e Chirurgia, Università di Milano-Bicocca, Ospedale San Gerardo/Fondazione MBBM, 20900 Monza, Italy.
| | - Paolo Grazioli
- Dipartimento di Scienze Della Salute, San Paolo Hospital Medical School, Università degli Studi di Milano, 20142 Milan, Italy.
| | - Valeria Scagliotti
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
| | - Mariavittoria Pasquini
- Dipartimento di Scienze Della Salute, San Paolo Hospital Medical School, Università degli Studi di Milano, 20142 Milan, Italy.
| | - Giovanni Cazzaniga
- Centro Ricerca M. Tettamanti, Clinica Pediatrica, Dipartimento di Medicina e Chirurgia, Università di Milano-Bicocca, Ospedale San Gerardo/Fondazione MBBM, 20900 Monza, Italy.
| | - Andrea Biondi
- Clinica Pediatrica, Dipartimento di Medicina e Chirurgia, Università di Milano-Bicocca Ospedale San Gerardo/Fondazione MBBM, 20900 Monza, Italy.
- Centro Ricerca M. Tettamanti, Clinica Pediatrica, Dipartimento di Medicina e Chirurgia, Università di Milano-Bicocca, Ospedale San Gerardo/Fondazione MBBM, 20900 Monza, Italy.
| | - Lidia Larizza
- Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, 20154 Milan, Italy.
| | | | - Carles Gaston-Massuet
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
| | - Valentina Massa
- Dipartimento di Scienze Della Salute, San Paolo Hospital Medical School, Università degli Studi di Milano, 20142 Milan, Italy.
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Alonso B, Beraud C, Meguellati S, Chen SW, Pellequer JL, Armengaud J, Godon C. Eukaryotic GPN-loop GTPases paralogs use a dimeric assembly reminiscent of archeal GPN. Cell Cycle 2013; 12:463-72. [PMID: 23324351 PMCID: PMC3587447 DOI: 10.4161/cc.23367] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
GTPases are molecular switches that regulate a wide-range of cellular processes. The GPN-loop GTPase (GPN) is a sub-family of P-loop NTPase that evolved from a single gene copy in archaea to triplicate paralog genes in eukaryotes, each having a non-redundant essential function in cell. In Saccharomyces cerevisiae, yGPN1 and yGPN2 are involved in sister chromatid cohesion mechanism, whereas nothing is known regarding yGPN3 function. Previous high-throughput experiments suggested that GPN paralogs interaction may occur. In this work, GPN|GPN contact was analyzed in details using TAP-Tag approach, yeast two-hybrid assay, in silico energy computation and site-directed mutagenesis of a conserved Glu residue located at the center of the interaction interface. It is demonstrated that this residue is essential for cell viability. A chromatid cohesion assay revealed that, like yGPN1 and yGPN2, yGPN3 also plays a role in sister chromatid cohesion. These results suggest that all three GPN proteins act at the molecular level in sister chromatid cohesion mechanism as a GPN|GPN complex reminiscent of the homodimeric structure of PAB0955, an archaeal member of GPN-loop GTPase.
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Affiliation(s)
- Béatrice Alonso
- CEA, iBEB, Service de Biochimie et Toxicologie Nucléaire/LBSP, Bagnols-sur-Cèze, France
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Rudra S, Skibbens RV. Cohesin codes - interpreting chromatin architecture and the many facets of cohesin function. J Cell Sci 2013; 126:31-41. [PMID: 23516328 PMCID: PMC3603509 DOI: 10.1242/jcs.116566] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Sister chromatid tethering is maintained by cohesin complexes that minimally contain Smc1, Smc3, Mcd1 and Scc3. During S-phase, chromatin-associated cohesins are modified by the Eco1/Ctf7 family of acetyltransferases. Eco1 proteins function during S phase in the context of replicated sister chromatids to convert chromatin-bound cohesins to a tethering-competent state, but also during G2 and M phases in response to double-stranded breaks to promote error-free DNA repair. Cohesins regulate transcription and are essential for ribosome biogenesis and complete chromosome condensation. Little is known, however, regarding the mechanisms through which cohesin functions are directed. Recent findings reveal that Eco1-mediated acetylation of different lysine residues in Smc3 during S phase promote either cohesion or condensation. Phosphorylation and SUMOylation additionally impact cohesin functions. Here, we posit the existence of a cohesin code, analogous to the histone code introduced over a decade ago, and speculate that there is a symphony of post-translational modifications that direct cohesins to function across a myriad of cellular processes. We also discuss evidence that outdate the notion that cohesion defects are singularly responsible for cohesion-mutant-cell inviability. We conclude by proposing that cohesion establishment is linked to chromatin formation.
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Affiliation(s)
| | - Robert V. Skibbens
- Department of Biological Sciences, 111 Research Drive, Lehigh University, Bethlehem, PA 18015, USA
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Horsfield JA, Print CG, Mönnich M. Diverse developmental disorders from the one ring: distinct molecular pathways underlie the cohesinopathies. Front Genet 2012; 3:171. [PMID: 22988450 PMCID: PMC3439829 DOI: 10.3389/fgene.2012.00171] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 08/17/2012] [Indexed: 11/13/2022] Open
Abstract
The multi-subunit protein complex, cohesin, is responsible for sister chromatid cohesion during cell division. The interaction of cohesin with DNA is controlled by a number of additional regulatory proteins. Mutations in cohesin, or its regulators, cause a spectrum of human developmental syndromes known as the “cohesinopathies.” Cohesinopathy disorders include Cornelia de Lange Syndrome and Roberts Syndrome. The discovery of novel roles for chromatid cohesion proteins in regulating gene expression led to the idea that cohesinopathies are caused by dysregulation of multiple genes downstream of mutations in cohesion proteins. Consistent with this idea, Drosophila, mouse, and zebrafish cohesinopathy models all show altered expression of developmental genes. However, there appears to be incomplete overlap among dysregulated genes downstream of mutations in different components of the cohesion apparatus. This is surprising because mutations in all cohesion proteins would be predicted to affect cohesin’s roles in cell division and gene expression in similar ways. Here we review the differences and similarities between genetic pathways downstream of components of the cohesion apparatus, and discuss how such differences might arise, and contribute to the spectrum of cohesinopathy disorders. We propose that mutations in different elements of the cohesion apparatus have distinct developmental outcomes that can be explained by sometimes subtly different molecular effects.
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Affiliation(s)
- Julia A Horsfield
- Department of Pathology, Dunedin School of Medicine, The University of Otago Dunedin, New Zealand
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Abstract
The cohesin complex holds the sister chromatids together from S-phase until the metaphase-to-anaphase transition, and ensures both their proper cohesion and timely separation. In addition to its canonical function in chromosomal segregation, cohesin has been suggested by several lines of investigation in recent years to play additional roles in apoptosis, DNA-damage response, transcriptional regulation and haematopoiesis. To better understand the basis of the disparate cellular functions of cohesin in these various processes, we have characterized a comprehensive protein interactome of cohesin-RAD21 by using three independent approaches: Y2H (yeast two-hybrid) screening, immunoprecipitation-coupled-MS of cytoplasmic and nuclear extracts from MOLT-4 T-lymphocytes in the presence and absence of etoposide-induced apoptosis, and affinity pull-down assays of chromatographically purified nuclear extracts from pro-apoptotic MOLT-4 cells. Our analyses revealed 112 novel protein interactors of cohesin-RAD21 that function in different cellular processes, including mitosis, regulation of apoptosis, chromosome dynamics, replication, transcription regulation, RNA processing, DNA-damage response, protein modification and degradation, and cytoskeleton and cell motility. Identification of cohesin interactors provides a framework for explaining the various non-canonical functions of the cohesin complex.
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Affiliation(s)
- Anil K Panigrahi
- Texas Children's Cancer Center, Department of Pediatric Hematology/Oncology, Baylor College of Medicine, Houston, 77030, USA
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Mönnich M, Kuriger Z, Print CG, Horsfield JA. A zebrafish model of Roberts syndrome reveals that Esco2 depletion interferes with development by disrupting the cell cycle. PLoS One 2011; 6:e20051. [PMID: 21637801 PMCID: PMC3102698 DOI: 10.1371/journal.pone.0020051] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 04/11/2011] [Indexed: 11/25/2022] Open
Abstract
The human developmental diseases Cornelia de Lange Syndrome (CdLS) and Roberts Syndrome (RBS) are both caused by mutations in proteins responsible for sister chromatid cohesion. Cohesion is mediated by a multi-subunit complex called cohesin, which is loaded onto chromosomes by NIPBL. Once on chromosomes, cohesin binding is stabilized in S phase upon acetylation by ESCO2. CdLS is caused by heterozygous mutations in NIPBL or cohesin subunits SMC1A and SMC3, and RBS is caused by homozygous mutations in ESCO2. The genetic cause of both CdLS and RBS reside within the chromosome cohesion apparatus, and therefore they are collectively known as "cohesinopathies". However, the two syndromes have distinct phenotypes, with differences not explained by their shared ontology. In this study, we have used the zebrafish model to distinguish between developmental pathways downstream of cohesin itself, or its acetylase ESCO2. Esco2 depleted zebrafish embryos exhibit features that resemble RBS, including mitotic defects, craniofacial abnormalities and limb truncations. A microarray analysis of Esco2-depleted embryos revealed that different subsets of genes are regulated downstream of Esco2 when compared with cohesin subunit Rad21. Genes downstream of Rad21 showed significant enrichment for transcriptional regulators, while Esco2-regulated genes were more likely to be involved the cell cycle or apoptosis. RNA in situ hybridization showed that runx1, which is spatiotemporally regulated by cohesin, is expressed normally in Esco2-depleted embryos. Furthermore, myca, which is downregulated in rad21 mutants, is upregulated in Esco2-depleted embryos. High levels of cell death contributed to the morphology of Esco2-depleted embryos without affecting specific developmental pathways. We propose that cell proliferation defects and apoptosis could be the primary cause of the features of RBS. Our results show that mutations in different elements of the cohesion apparatus have distinct developmental outcomes, and provide insight into why CdLS and RBS are distinct diseases.
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Affiliation(s)
- Maren Mönnich
- Department of Pathology, Dunedin School of Medicine, The University of Otago, Dunedin, New Zealand
| | - Zoë Kuriger
- Department of Pathology, Dunedin School of Medicine, The University of Otago, Dunedin, New Zealand
| | - Cristin G. Print
- Department of Molecular Medicine and Pathology, School of Medical Sciences, and the Bioinformatics Institute, The University of Auckland, Auckland, New Zealand
| | - Julia A. Horsfield
- Department of Pathology, Dunedin School of Medicine, The University of Otago, Dunedin, New Zealand
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Abstract
Vertebrate development requires the formation of multiple cell types from a single genetic blueprint, an extraordinary feat that is guided by the dynamic and finely tuned reprogramming of gene expression. The sophisticated orchestration of gene expression programs is driven primarily by changes in the patterns of covalent chromatin modifications. These epigenetic changes are directed by cis elements, positioned across the genome, which provide docking sites for transcription factors and associated chromatin modifiers. Epigenetic changes impact all aspects of gene regulation, governing association with the machinery that drives transcription, replication, repair and recombination, a regulatory relationship that is dramatically illustrated in developing lymphocytes. The program of somatic rearrangements that assemble antigen receptor genes in precursor B and T cells has proven to be a fertile system for elucidating relationships between the genetic and epigenetic components of gene regulation. This chapter describes our current understanding of the cross-talk between key genetic elements and epigenetic programs during recombination of the Tcrb locus in developing T cells, how each contributes to the regulation of chromatin accessibility at individual DNA targets for recombination, and potential mechanisms that coordinate their actions.
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