151
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Hong W, Zhu H, Potter CJ, Barsh G, Kurusu M, Zinn K, Luo L. Leucine-rich repeat transmembrane proteins instruct discrete dendrite targeting in an olfactory map. Nat Neurosci 2009; 12:1542-50. [PMID: 19915565 PMCID: PMC2826190 DOI: 10.1038/nn.2442] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/01/2009] [Indexed: 11/09/2022]
Abstract
Olfactory systems utilize discrete neural pathways to process and integrate odorant information. In Drosophila, axons of first-order olfactory receptor neurons (ORNs) and dendrites of second-order projection neurons (PNs) form class-specific synaptic connections at approximately 50 glomeruli. The mechanisms underlying PN dendrite targeting to distinct glomeruli in a three-dimensional discrete neural map are unclear. We found that the leucine-rich repeat (LRR) transmembrane protein Capricious (Caps) was differentially expressed in different classes of PNs. Loss-of-function and gain-of-function studies indicated that Caps instructs the segregation of Caps-positive and Caps-negative PN dendrites to discrete glomerular targets. Moreover, Caps-mediated PN dendrite targeting was independent of presynaptic ORNs and did not involve homophilic interactions. The closely related protein Tartan was partially redundant with Caps. These LRR proteins are probably part of a combinatorial cell-surface code that instructs discrete olfactory map formation.
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Affiliation(s)
- Weizhe Hong
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, California, USA
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152
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Nativio R, Wendt KS, Ito Y, Huddleston JE, Uribe-Lewis S, Woodfine K, Krueger C, Reik W, Peters JM, Murrell A. Cohesin is required for higher-order chromatin conformation at the imprinted IGF2-H19 locus. PLoS Genet 2009; 5:e1000739. [PMID: 19956766 PMCID: PMC2776306 DOI: 10.1371/journal.pgen.1000739] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Accepted: 10/23/2009] [Indexed: 01/09/2023] Open
Abstract
Cohesin is a chromatin-associated protein complex that mediates sister chromatid cohesion by connecting replicated DNA molecules. Cohesin also has important roles in gene regulation, but the mechanistic basis of this function is poorly understood. In mammalian genomes, cohesin co-localizes with CCCTC binding factor (CTCF), a zinc finger protein implicated in multiple gene regulatory events. At the imprinted IGF2-H19 locus, CTCF plays an important role in organizing allele-specific higher-order chromatin conformation and functions as an enhancer blocking transcriptional insulator. Here we have used chromosome conformation capture (3C) assays and RNAi-mediated depletion of cohesin to address whether cohesin affects higher order chromatin conformation at the IGF2-H19 locus in human cells. Our data show that cohesin has a critical role in maintaining CTCF-mediated chromatin conformation at the locus and that disruption of this conformation coincides with changes in IGF2 expression. We show that the cohesin-dependent, higher-order chromatin conformation of the locus exists in both G1 and G2 phases of the cell cycle and is therefore independent of cohesin's function in sister chromatid cohesion. We propose that cohesin can mediate interactions between DNA molecules in cis to insulate genes through the formation of chromatin loops, analogous to the cohesin mediated interaction with sister chromatids in trans to establish cohesion.
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Affiliation(s)
- Raffaella Nativio
- Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom
| | | | - Yoko Ito
- Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom
| | - Joanna E. Huddleston
- Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom
| | - Santiago Uribe-Lewis
- Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom
| | - Kathryn Woodfine
- Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom
| | - Christel Krueger
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge, United Kingdom
| | - Wolf Reik
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge, United Kingdom
- Centre for Trophoblast Research, University of Cambridge, Cambridge, United Kingdom
| | | | - Adele Murrell
- Department of Oncology, University of Cambridge, Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom
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153
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A genetic pathway composed of Sox14 and Mical governs severing of dendrites during pruning. Nat Neurosci 2009; 12:1497-505. [PMID: 19881505 PMCID: PMC3101876 DOI: 10.1038/nn.2415] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 09/04/2009] [Indexed: 11/08/2022]
Abstract
Pruning that selectively eliminates neuronal processes is crucial for the refinement of neural circuits during development. In Drosophila, the class IV dendritic arborization neuron (ddaC) undergoes pruning to remove its larval dendrites during metamorphosis. We identified Sox14 as a transcription factor that was necessary and sufficient to mediate dendrite severing during pruning in response to ecdysone signaling. We found that Sox14 mediated dendrite pruning by directly regulating the expression of the target gene mical. mical Encodes a large cytosolic protein with multiple domains that are known to associate with cytoskeletal components. mical Mutants had marked severing defects during dendrite pruning that were similar to those of sox14 mutants. Overexpression of Mical could significantly rescue pruning defects in sox14 mutants, suggesting that Mical is a major downstream target of Sox14 during pruning. Thus, our findings indicate that a previously unknown pathway composed of Sox14 and its cytoskeletal target Mical governs dendrite severing.
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154
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Kogut I, Wang J, Guacci V, Mistry RK, Megee PC. The Scc2/Scc4 cohesin loader determines the distribution of cohesin on budding yeast chromosomes. Genes Dev 2009; 23:2345-57. [PMID: 19797771 PMCID: PMC2758738 DOI: 10.1101/gad.1819409] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Accepted: 08/14/2009] [Indexed: 01/05/2023]
Abstract
Cohesins mediate sister chromatid cohesion and DNA repair and also function in gene regulation. Chromosomal cohesins are distributed nonrandomly, and their deposition requires the heterodimeric Scc2/Scc4 loader. Whether Scc2/Scc4 establishes nonrandom cohesin distributions on chromosomes is poorly characterized, however. To better understand the spatial regulation of cohesin association, we mapped budding yeast Scc2 and Scc4 chromosomal distributions. We find that Scc2/Scc4 resides at previously mapped cohesin-associated regions (CARs) in pericentromeric and arm regions, and that Scc2/Scc4-cohesin colocalization persists after the initial deposition of cohesins in G1/S phase. Pericentromeric Scc2/Scc4 enrichment is kinetochore-dependent, and both Scc2/Scc4 and cohesin associations are coordinately reduced in these regions following chromosome biorientation. Thus, these characteristics of Scc2/Scc4 binding closely recapitulate those of cohesin. Although present in G1, Scc2/Scc4 initially has a poor affinity for CARs, but its affinity increases as cells traverse the cell cycle. Scc2/Scc4 association with CARs is independent of cohesin, however. Taken together, these observations are inconsistent with a previous suggestion that cohesins are relocated by translocating RNA polymerases from separate loading sites to intergenic regions between convergently transcribed genes. Rather, our findings suggest that budding yeast cohesins are targeted to CARs largely by Scc2/Scc4 loader association at these locations.
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Affiliation(s)
- Igor Kogut
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Jianbin Wang
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Vincent Guacci
- Carnegie Institution of Washington, Baltimore, Maryland 21218, USA
| | - Rohinton K. Mistry
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Paul C. Megee
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
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155
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Abstract
Cornelia de Lange syndrome (CdLS) (OMIM #122470, #300590 and #610759) is a dominant genetic disorder with multiple organ system abnormalities which is classically characterized by typical facial features, growth and mental retardation, upper limb defects, hirsutism, gastrointestinal and other visceral system involvement. Mutations in three cohesin proteins, a key regulator of cohesin, NIPBL, and two structural components of the cohesin ring SMC1A and SMC3, etiologically account for about 65% of individuals with CdLS. Cohesin controls faithful chromosome segregation during the mitotic and meiotic cell cycles. Multiple proteins in the cohesin pathway are also involved in additional fundamental biological events such as double-strand DNA break repair and long-range regulation of transcription. Moreover, chromosome instability was recently associated with defective sister chromatid cohesion in several cancer studies, and an increasing number of human developmental disorders is being reported to result from disruption of this pathway. Here, we will discuss the human disorders caused by alterations of cohesin function (termed 'cohesinopathies'), with an emphasis on the clinical manifestations of CdLS and mechanistic studies of the CdLS-related proteins.
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Affiliation(s)
- J Liu
- Division of Human Molecular Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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156
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Kishi S, Slack BE, Uchiyama J, Zhdanova IV. Zebrafish as a genetic model in biological and behavioral gerontology: where development meets aging in vertebrates--a mini-review. Gerontology 2009; 55:430-41. [PMID: 19654474 DOI: 10.1159/000228892] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 03/12/2009] [Indexed: 01/10/2023] Open
Abstract
Understanding the molecular mechanisms of aging in vertebrates is a major challenge of modern biology and biomedical science. This is due, in part, to the complexity of the aging process and its multifactorial nature, the paucity of animal models that lend themselves to unbiased high-throughput screening for aging phenotypes, and the difficulty of predicting such phenotypes at an early age. We suggest that the zebrafish genetic model offers a unique opportunity to fill in this gap and contributes to advances in biological and behavioral gerontology. Our recent studies demonstrated that this diurnal vertebrate with gradual senescence is an excellent model in which to study age-dependent changes in musculoskeletal and eye morphology, endocrine factors, gene expression, circadian clock, sleep and cognitive functions. Importantly, we have also found that the presence of a senescence-associated biomarker ('senescence-associated beta-galactosidase') can be documented during early zebrafish development and is predictive of premature aging phenotypes later in adult life. The availability of mutant 'genotypes' with identified aging 'phenotypes' in zebrafish, in combination with a wealth of information about zebrafish development and genetics, and the existence of multiple mutant and transgenic lines, should significantly facilitate the use of this outstanding vertebrate model in deciphering the mechanisms of aging, and in developing preventive and therapeutic strategies to prolong the productive life span ('health span') in humans.
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Affiliation(s)
- Shuji Kishi
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, FL 33458, USA.
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157
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Hadjur S, Williams LM, Ryan NK, Cobb BS, Sexton T, Fraser P, Fisher AG, Merkenschlager M. Cohesins form chromosomal cis-interactions at the developmentally regulated IFNG locus. Nature 2009; 460:410-3. [PMID: 19458616 PMCID: PMC2869028 DOI: 10.1038/nature08079] [Citation(s) in RCA: 420] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 04/27/2009] [Indexed: 12/24/2022]
Abstract
Cohesin-mediated sister chromatid cohesion is essential for chromosome segregation and post-replicative DNA repair. In addition, evidence from model organisms and from human genetics suggests that cohesin is involved in the control of gene expression. This non-canonical role has recently been rationalized by the findings that mammalian cohesin complexes are recruited to a subset of DNase I hypersensitive sites and to conserved noncoding sequences by the DNA-binding protein CTCF. CTCF functions at insulators (which control interactions between enhancers and promoters) and at boundary elements (which demarcate regions of distinct chromatin structure), and cohesin contributes to its enhancer-blocking activity. The underlying mechanisms remain unknown, and the full spectrum of cohesin functions remains to be determined. Here we show that cohesin forms the topological and mechanistic basis for cell-type-specific long-range chromosomal interactions in cis at the developmentally regulated cytokine locus IFNG. Hence, the ability of cohesin to constrain chromosome topology is used not only for the purpose of sister chromatid cohesion, but also to dynamically define the spatial conformation of specific loci. This new aspect of cohesin function is probably important for normal development and disease.
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Affiliation(s)
- Suzana Hadjur
- Lymphocyte Development Group, MRC Clinical Sciences Centre, Imperial College London, Du Cane Road, London W12 0NN, UK
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158
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Schaaf CA, Misulovin Z, Sahota G, Siddiqui AM, Schwartz YB, Kahn TG, Pirrotta V, Gause M, Dorsett D. Regulation of the Drosophila Enhancer of split and invected-engrailed gene complexes by sister chromatid cohesion proteins. PLoS One 2009; 4:e6202. [PMID: 19587787 PMCID: PMC2703808 DOI: 10.1371/journal.pone.0006202] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 06/16/2009] [Indexed: 01/14/2023] Open
Abstract
The cohesin protein complex was first recognized for holding sister chromatids together and ensuring proper chromosome segregation. Cohesin also regulates gene expression, but the mechanisms are unknown. Cohesin associates preferentially with active genes, and is generally absent from regions in which histone H3 is methylated by the Enhancer of zeste [E(z)] Polycomb group silencing protein. Here we show that transcription is hypersensitive to cohesin levels in two exceptional cases where cohesin and the E(z)-mediated histone methylation simultaneously coat the entire Enhancer of split and invected-engrailed gene complexes in cells derived from Drosophila central nervous system. These gene complexes are modestly transcribed, and produce seven of the twelve transcripts that increase the most with cohesin knockdown genome-wide. Cohesin mutations alter eye development in the same manner as increased Enhancer of split activity, suggesting that similar regulation occurs in vivo. We propose that cohesin helps restrain transcription of these gene complexes, and that deregulation of similarly cohesin-hypersensitive genes may underlie developmental deficits in Cornelia de Lange syndrome.
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Affiliation(s)
- Cheri A. Schaaf
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Ziva Misulovin
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Gurmukh Sahota
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Akbar M. Siddiqui
- Microarray Core Facility, Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Yuri B. Schwartz
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Tatyana G. Kahn
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Vincenzo Pirrotta
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Maria Gause
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Dale Dorsett
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
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159
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Barbero JL. Cohesins: chromatin architects in chromosome segregation, control of gene expression and much more. Cell Mol Life Sci 2009; 66:2025-35. [PMID: 19290475 PMCID: PMC11115881 DOI: 10.1007/s00018-009-0004-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 02/02/2009] [Accepted: 02/05/2009] [Indexed: 10/21/2022]
Abstract
Cells have evolved to develop molecules and control mechanisms that guarantee correct chromosome segregation and ensure the proper distribution of genetic material to daughter cells. In this sense, the establishment, maintenance, and removal of sister chromatid cohesion is one of the most fascinating and dangerous processes in the life of a cell because errors in the control of these processes frequently lead to cell death or aneuploidy. The main protagonist in this mechanism is a four-protein complex denominated the cohesin complex. In the last 10 years, we have improved our understanding of the key players in the regulation of sister chromatid cohesion during cell division in mitosis and meiosis. The last 2 years have seen an increase in evidence showing that cohesins have important functions in non-dividing cells, revealing new, unexplored roles for these proteins in the control of gene expression, development, and other essential cell functions in mammals.
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Affiliation(s)
- José L Barbero
- Departamento de Biología Celular y del Desarrollo, Centro de Investigaciones Biológicas (CSIC), C/Ramiro de Maeztu 9, 28040, Madrid, Spain.
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160
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Frank CL, Tsai LH. Alternative functions of core cell cycle regulators in neuronal migration, neuronal maturation, and synaptic plasticity. Neuron 2009; 62:312-26. [PMID: 19447088 DOI: 10.1016/j.neuron.2009.03.029] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 03/26/2009] [Accepted: 03/30/2009] [Indexed: 12/13/2022]
Abstract
Recent studies have demonstrated that boundaries separating a cycling cell from a postmitotic neuron are not as concrete as expected. Novel and unique physiological functions in neurons have been ascribed for proteins fundamentally required for cell cycle progression and control. These "core" cell cycle regulators serve diverse postmitotic functions that span various developmental stages of a neuron, including neuronal migration, axonal elongation, axon pruning, dendrite morphogenesis, and synaptic maturation and plasticity. In this review, we detail the nonproliferative postmitotic roles that these cell cycle proteins have recently been reported to play, the significance of their expression in neurons, mechanistic insight when available, and future prospects.
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Affiliation(s)
- Christopher L Frank
- Massachusetts Institute of Technology, Department of Brain and Cognitive Sciences, Howard Hughes Medical Institute, Cambridge, MA 02139, USA
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161
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Liu J, Zhang Z, Bando M, Itoh T, Deardorff MA, Clark D, Kaur M, Tandy S, Kondoh T, Rappaport E, Spinner NB, Vega H, Jackson LG, Shirahige K, Krantz ID. Transcriptional dysregulation in NIPBL and cohesin mutant human cells. PLoS Biol 2009; 7:e1000119. [PMID: 19468298 PMCID: PMC2680332 DOI: 10.1371/journal.pbio.1000119] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 04/17/2009] [Indexed: 01/13/2023] Open
Abstract
Genome-wide studies using cells from patients with Cornelia de Lange Syndrome reveal a role for cohesin in regulating gene expression in human cells. Cohesin regulates sister chromatid cohesion during the mitotic cell cycle with Nipped-B-Like (NIPBL) facilitating its loading and unloading. In addition to this canonical role, cohesin has also been demonstrated to play a critical role in regulation of gene expression in nondividing cells. Heterozygous mutations in the cohesin regulator NIPBL or cohesin structural components SMC1A and SMC3 result in the multisystem developmental disorder Cornelia de Lange Syndrome (CdLS). Genome-wide assessment of transcription in 16 mutant cell lines from severely affected CdLS probands has identified a unique profile of dysregulated gene expression that was validated in an additional 101 samples and correlates with phenotypic severity. This profile could serve as a diagnostic and classification tool. Cohesin binding analysis demonstrates a preference for intergenic regions suggesting a cis-regulatory function mimicking that of a boundary/insulator interacting protein. However, the binding sites are enriched within the promoter regions of the dysregulated genes and are significantly decreased in CdLS proband, indicating an alternative role of cohesin as a transcription factor. Appropriate segregation of chromosomes to daughter cells depends upon proper cohesion of sister chromatids during mitosis. The multiprotein cohesin complex and its regulators are key factors in this process. Intriguingly, recent work has shown that the cohesin complex also has other cellular roles, including a role in regulating gene expression. Additionally, mutations in cohesin structural and regulatory components have been linked to human multisystem developmental disorders such as Cornelia de Lange Syndrome (CdLS), but the role cohesin is playing in the pathogenesis of this disorder is unknown. To define the role that cohesin plays in regulating gene expression in human cells, we analyzed gene expression and genome-wide cohesin binding patterns in cells from normal subjects and from CdLS probands with mutations in the cohesin regulator NIPBL or in the cohesin structural component SMC1A. We found a strikingly conserved pattern of gene dysregulation in these different cell lines that correlates with disease severity and a significant correlation between gene dysregulation and cohesin binding around misexpressed genes. The observed pattern of binding and misexpression is consistent with cohesin having a putative role as a boundary/insulator interacting protein or transcription factor, the activity of which is disrupted in CdLS probands.
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Affiliation(s)
- Jinglan Liu
- Division of Human Genetics, Abramson Research Institute, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Zhe Zhang
- Center for Biomedical Informatics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Masashige Bando
- Laboratory of Chromosome Structure and Function, Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama City, Kanagawa, Japan
| | - Takehiko Itoh
- Laboratory of Chromosome Structure and Function, Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama City, Kanagawa, Japan
| | - Matthew A. Deardorff
- Division of Human Genetics, Abramson Research Institute, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Dinah Clark
- Division of Human Genetics, Abramson Research Institute, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Maninder Kaur
- Division of Human Genetics, Abramson Research Institute, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Stephany Tandy
- Division of Human Genetics, Abramson Research Institute, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Tatsuro Kondoh
- Division of Developmental Disability, Misakaenosono Mutsumi Developmental, Medical, and Welfare Center, Isahaya, Japan
| | - Eric Rappaport
- NAPCORE, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Nancy B. Spinner
- Division of Human Genetics, Abramson Research Institute, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Hugo Vega
- Instituto de Genética, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Laird G. Jackson
- Department of Obstetrics and Gynecology, Drexel University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Katsuhiko Shirahige
- Laboratory of Chromosome Structure and Function, Department of Biological Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama City, Kanagawa, Japan
| | - Ian D. Krantz
- Division of Human Genetics, Abramson Research Institute, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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162
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Zhang B, Chang J, Fu M, Huang J, Kashyap R, Salavaggione E, Jain S, Shashikant K, Deardorff MA, Uzielli MLG, Dorsett D, Beebe DC, Jay PY, Heuckeroth RO, Krantz I, Milbrandt J. Dosage effects of cohesin regulatory factor PDS5 on mammalian development: implications for cohesinopathies. PLoS One 2009; 4:e5232. [PMID: 19412548 PMCID: PMC2672303 DOI: 10.1371/journal.pone.0005232] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 03/06/2009] [Indexed: 01/09/2023] Open
Abstract
Cornelia de Lange syndrome (CdLS), a disorder caused by mutations in cohesion proteins, is characterized by multisystem developmental abnormalities. PDS5, a cohesion protein, is important for proper chromosome segregation in lower organisms and has two homologues in vertebrates (PDS5A and PDS5B). Pds5B mutant mice have developmental abnormalities resembling CdLS; however the role of Pds5A in mammals and the association of PDS5 proteins with CdLS are unknown. To delineate genetic interactions between Pds5A and Pds5B and explore mechanisms underlying phenotypic variability, we generated Pds5A-deficient mice. Curiously, these mice exhibit multiple abnormalities that were previously observed in Pds5B-deficient mice, including cleft palate, skeletal patterning defects, growth retardation, congenital heart defects and delayed migration of enteric neuron precursors. They also frequently display renal agenesis, an abnormality not observed in Pds5B(-/-) mice. While Pds5A(-/-) and Pds5B(-/-) mice die at birth, embryos harboring 3 mutant Pds5 alleles die between E11.5 and E12.5 most likely of heart failure, indicating that total Pds5 gene dosage is critical for normal development. In addition, characterization of these compound homozygous-heterozygous mice revealed a severe abnormality in lens formation that does not occur in either Pds5A(-/-) or Pds5B(-/-) mice. We further identified a functional missense mutation (R1292Q) in the PDS5B DNA-binding domain in a familial case of CdLS, in which affected individuals also develop megacolon. This study shows that PDS5A and PDS5B functions other than those involving chromosomal dynamics are important for normal development, highlights the sensitivity of key developmental processes on PDS5 signaling, and provides mechanistic insights into how PDS5 mutations may lead to CdLS.
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Affiliation(s)
- Bin Zhang
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Jufang Chang
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Ming Fu
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Jie Huang
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Rakesh Kashyap
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
- Department of Genetics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Ezequiel Salavaggione
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Sanjay Jain
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, United States of America
- Department of Medicine (Renal Division), Washington University School of Medicine, St Louis, Missouri, United States of America
- HOPE Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Kulkarni Shashikant
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, United States of America
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Matthew A. Deardorff
- Division of Human and Molecular Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | | | - Dale Dorsett
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - David C. Beebe
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Patrick Y. Jay
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
- Department of Genetics, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Robert O. Heuckeroth
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, United States of America
- HOPE Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Ian Krantz
- Division of Human and Molecular Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Jeffrey Milbrandt
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, United States of America
- HOPE Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri, United States of America
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163
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Wendt KS, Peters JM. How cohesin and CTCF cooperate in regulating gene expression. Chromosome Res 2009; 17:201-14. [PMID: 19308701 DOI: 10.1007/s10577-008-9017-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 10/20/2008] [Accepted: 10/22/2008] [Indexed: 11/30/2022]
Abstract
Cohesin is a DNA-binding protein complex that is essential for sister chromatid cohesion and facilitates the repair of damaged DNA. In addition, cohesin has important roles in regulating gene expression, but the molecular mechanisms of this function are poorly understood. Recent experiments have revealed that cohesin binds to the same sites in mammalian genomes as the zinc finger transcription factor CTCF. At a few loci CTCF has been shown to function as an enhancer-blocking transcriptional insulator, and recent observations indicate that this function depends on cohesin. Here we review what is known about the roles of cohesin and CTCF in regulating gene expression in mammalian cells, and we discuss how cohesin might mediate the insulator function of CTCF.
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Affiliation(s)
- Kerstin S Wendt
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
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164
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White GE, Erickson HP. The coiled coils of cohesin are conserved in animals, but not in yeast. PLoS One 2009; 4:e4674. [PMID: 19262687 PMCID: PMC2650401 DOI: 10.1371/journal.pone.0004674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Accepted: 01/27/2009] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The SMC proteins are involved in DNA repair, chromosome condensation, and sister chromatid cohesion throughout Eukaryota. Long, anti-parallel coiled coils are a prominent feature of SMC proteins, and are thought to serve as spacer rods to provide an elongated structure and to separate domains. We reported recently that the coiled coils of mammalian condensin (SMC2/4) showed moderate sequence divergence (approximately 10-15%) consistent with their functioning as spacer rods. The coiled coils of mammalian cohesins (SMC1/3), however, were very highly constrained, with amino acid sequence divergence typically <0.5%. These coiled coils are among the most highly conserved mammalian proteins, suggesting that they make extensive contacts over their entire surface. METHODOLOGY/PRINCIPAL FINDINGS Here, we broaden our initial analysis of condensin and cohesin to include additional vertebrate and invertebrate organisms and multiple species of yeast. We found that the coiled coils of SMC1/3 are highly constrained in Drosophila and other insects, and more generally across all animal species. However, in yeast they are no more constrained than the coils of SMC2/4 and Ndc80/Nuf2p, suggesting that they are serving primarily as spacer rods. CONCLUSIONS/SIGNIFICANCE SMC1/3 functions for sister chromatid cohesion in all species. Since its coiled coils apparently serve only as spacer rods in yeast, it is likely that this is sufficient for sister chromatid cohesion in all species. This suggests an additional function in animals that constrains the sequence of the coiled coils. Several recent studies have demonstrated that cohesin has a role in gene expression in post-mitotic neurons of Drosophila, and other animal cells. Some variants of human Cornelia de Lange Syndrome involve mutations in human SMC1/3. We suggest that the role of cohesin in gene expression may involve intimate contact of the coiled coils of SMC1/3, and impose the constraint on sequence divergence.
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Affiliation(s)
- Glenn E. White
- Department of Biological and Environmental Sciences, Longwood University, Farmville, Virginia, United Kingdom
| | - Harold P. Erickson
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, United States of America
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165
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Bessat M, Ersfeld K. Functional characterization of cohesin SMC3 and separase and their roles in the segregation of large and minichromosomes in Trypanosoma brucei. Mol Microbiol 2009; 71:1371-85. [PMID: 19183276 DOI: 10.1111/j.1365-2958.2009.06611.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Minichromosomes in the nuclear genome of Trypanosoma brucei exhibit unusual patterns of mitotic segregation. To address whether differences in their mode of segregation in relation to large chromosomes are reflected at a molecular level, we characterized two different proteins that have highly conserved functions in eukaryotic chromosomes segregation: the SMC3 protein, a component of the chromatid cohesion apparatus, and the protease separase that resolves the cohesin complex at the onset of anaphase and has, in other organisms, additional functions during mitosis. Using in situ hybridization we show that RNA interference-mediated depletion of SMC3 has no visible effect on the segregation of the minichromosomal population but interferes with the faithful mitotic separation of large chromosomes. In contrast, separase depletion causes missegregation of both mini- and large chromosomes. We also show that SMC3 persists as a soluble protein throughout the cell cycle and only associates with chromatin between G1 and metaphase. Separase is present in the cell during the entire cell cycle, but is excluded from the nucleus until the metaphase-anaphase transition, thereby providing a potential control mechanism to prevent the untimely cleavage of the cohesin complex.
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Affiliation(s)
- Mohamed Bessat
- Department of Biological Sciences, University of Hull, Hull, UK
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166
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Abstract
Cornelia de Lange syndrome (CdLS) is genetically heterogeneous and is usually sporadic, occurring approximately once per 10,000 births. CdLS individuals display diverse and variable deficits in growth, mental development, limbs, and organs. In the past few years it has been shown that CdLS is caused by gene mutations affecting proteins involved in sister chromatid cohesion. Studies in model organisms, and more recently in human cells, have revealed, somewhat unexpectedly, that the developmental deficits in CdLS likely arise from changes in gene expression. The mechanisms by which cohesion factors regulate gene expression remain to be elucidated, but current data suggest that they likely regulate transcription in multiple ways.
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Affiliation(s)
- Dale Dorsett
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Boulevard, Saint Louis, MO 63104, USA.
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167
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Aso Y, Grübel K, Busch S, Friedrich AB, Siwanowicz I, Tanimoto H. The mushroom body of adult Drosophila characterized by GAL4 drivers. J Neurogenet 2009; 23:156-72. [PMID: 19140035 DOI: 10.1080/01677060802471718] [Citation(s) in RCA: 280] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The mushroom body is required for a variety of behaviors of Drosophila melanogaster. Different types of intrinsic and extrinsic mushroom body neurons might underlie its functional diversity. There have been many GAL4 driver lines identified that prominently label the mushroom body intrinsic neurons, which are known as "Kenyon cells." Under one constant experimental condition, we analyzed and compared the the expression patterns of 25 GAL4 drivers labeling the mushroom body. As an internet resource, we established a digital catalog indexing representative confocal data of them. Further more, we counted the number of GAL4-positive Kenyon cells in each line. We found that approximately 2,000 Kenyon cells can be genetically labeled in total. Three major Kenyon cell subtypes, the gamma, alpha'/beta', and alpha/beta neurons, respectively, contribute to 33, 18, and 49% of 2,000 Kenyon cells. Taken together, this study lays groundwork for functional dissection of the mushroom body.
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Affiliation(s)
- Yoshinori Aso
- Max-Planck-Institut für Neurobiologie, Martinsried, Germany
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168
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Abstract
The cohesin complex, discovered through its role in sister chromatid cohesion, also plays roles in gene expression and development in organisms from yeast to human. This review highlights what has been learned about the gene control and developmental functions of cohesin and the Nipped-B (NIPBL/Scc2) cohesin loading factor in Drosophila. The Drosophila studies have provided unique insights into the aetiology of Cornelia de Lange syndrome (CdLS), which is caused by mutations affecting sister chromatid cohesion proteins in humans. In vivo experiments with Drosophila show that cohesin and Nipped-B have dosage-sensitive effects on the functions of many evolutionarily conserved genes and developmental pathways. Genome-wide studies with Drosophila cultured cells show that Nipped-B and cohesin co-localize on chromosomes, and bind preferentially, but not exclusively, to many actively transcribed genes and their regulatory sequences, including many of the proposed in vivo target genes. In contrast, the cohesion factors are largely excluded from genes silenced by Polycomb group (PcG) proteins. Combined, the in vivo genetic data and the binding patterns of cohesin and Nipped-B in cultured cells are consistent with the hypothesis that they control the action of gene regulatory sequences, including transcriptional enhancers and insulators, and suggest that they might also help define active chromatin domains and influence transcriptional elongation.
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Affiliation(s)
- Dale Dorsett
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Boulevard, Saint Louis, MO 63104, USA.
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169
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Abstract
The cohesin complex is a major constituent of interphase and mitotic chromosomes. Apart from its role in mediating sister chromatid cohesion, it is also important for DNA double-strand-break repair and transcriptional control. The functions of cohesin are regulated by phosphorylation, acetylation, ATP hydrolysis, and site-specific proteolysis. Recent evidence suggests that cohesin acts as a novel topological device that traps chromosomal DNA within a large tripartite ring formed by its core subunits.
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Affiliation(s)
- Kim Nasmyth
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
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170
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McNairn AJ, Gerton JL. Cohesinopathies: One ring, many obligations. Mutat Res 2008; 647:103-11. [PMID: 18786550 DOI: 10.1016/j.mrfmmm.2008.08.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/31/2008] [Accepted: 08/07/2008] [Indexed: 12/24/2022]
Abstract
Over 75 years ago, two human genetic disorders were initially described and named for their founding physicians: Cornelia de Lange (CdLS) and Roberts syndrome (RBS)/SC Phocomelia (SC). In the past 4 years, genetic studies of patients have revealed the primary genes involved in these disorders are the essential, evolutionarily conserved components of the cohesin pathway. This pathway serves to facilitate cohesion between replicated sister chromatids, thereby enabling proper chromosome segregation. As a result of these findings, these disorders now represent a novel class of human genetic disorders known as cohesinopathies. Over 60% of CdLS patients examined have de novo mutations in either: SCC2/NIPBL, SMC1, or SMC3, whereas the causative gene in Roberts syndrome and SC Phocomelia has been identified as ESCO2. Now modern genetic, biochemical, and cell biological approaches may be applied to determine the underlying mechanism of these genetic disorders.
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Affiliation(s)
- Adrian J McNairn
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
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171
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Abstract
Cohesin is a chromosome-associated multisubunit protein complex that is highly conserved in eukaryotes and has close homologs in bacteria. Cohesin mediates cohesion between replicated sister chromatids and is therefore essential for chromosome segregation in dividing cells. Cohesin is also required for efficient repair of damaged DNA and has important functions in regulating gene expression in both proliferating and post-mitotic cells. Here we discuss how cohesin associates with DNA, how these interactions are controlled during the cell cycle; how binding of cohesin to DNA may mediate sister chromatid cohesion, DNA repair, and gene regulation; and how defects in these processes can lead to human disease.
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Affiliation(s)
- Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), A-1030 Vienna, Austria.
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172
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MicroRNA processing pathway regulates olfactory neuron morphogenesis. Curr Biol 2008; 18:1754-9. [PMID: 19013069 DOI: 10.1016/j.cub.2008.09.045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 09/13/2008] [Accepted: 09/17/2008] [Indexed: 12/19/2022]
Abstract
The microRNA (miRNA) processing pathway produces miRNAs as posttranscriptional regulators of gene expression. The nuclear RNase III Drosha catalyzes the first processing step together with the dsRNA binding protein DGCR8/Pasha generating pre-miRNAs [1, 2]. The next cleavage employs the cytoplasmic RNase III Dicer producing miRNA duplexes [3, 4]. Finally, Argonautes are recruited with miRNAs into an RNA-induced silencing complex for mRNA recognition (Figure 1A). Here, we identify two members of the miRNA pathway, Pasha and Dicer-1, in a forward genetic screen for mutations that disrupt wiring specificity of Drosophila olfactory projection neurons (PNs). The olfactory system is built as discrete map of highly stereotyped neuronal connections [5, 6]. Each PN targets dendrites to a specific glomerulus in the antennal lobe and projects axons stereotypically into higher brain centers [7-9]. In selected PN classes, pasha and Dicer-1 mutants cause specific PN dendrite mistargeting in the antennal lobe and altered axonal terminations in higher brain centers. Furthermore, Pasha and Dicer-1 act cell autonomously in postmitotic neurons to regulate dendrite and axon targeting during development. However, Argonaute-1 and Argonaute-2 are dispensable for PN morphogenesis. Our findings suggest a role for the miRNA processing pathway in establishing wiring specificity in the nervous system.
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173
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A screen of cell-surface molecules identifies leucine-rich repeat proteins as key mediators of synaptic target selection. Neuron 2008; 59:972-85. [PMID: 18817735 DOI: 10.1016/j.neuron.2008.07.037] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 06/20/2008] [Accepted: 07/29/2008] [Indexed: 01/16/2023]
Abstract
In Drosophila embryos and larvae, a small number of identified motor neurons innervate body wall muscles in a highly stereotyped pattern. Although genetic screens have identified many proteins that are required for axon guidance and synaptogenesis in this system, little is known about the mechanisms by which muscle fibers are defined as targets for specific motor axons. To identify potential target labels, we screened 410 genes encoding cell-surface and secreted proteins, searching for those whose overexpression on all muscle fibers causes motor axons to make targeting errors. Thirty such genes were identified, and a number of these were members of a large gene family encoding proteins whose extracellular domains contain leucine-rich repeat (LRR) sequences, which are protein interaction modules. By manipulating gene expression in muscle 12, we showed that four LRR proteins participate in the selection of this muscle as the appropriate synaptic target for the RP5 motor neuron.
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174
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Takagi M, Bunai K, Yanagi KI, Imamoto N. Cloning of Xenopus orthologs of Ctf7/Eco1 acetyltransferase and initial characterization of XEco2. FEBS J 2008; 275:6109-22. [PMID: 19016859 DOI: 10.1111/j.1742-4658.2008.06736.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sister chromatid cohesion is important for the correct alignment and segregation of chromosomes during cell division. Although the cohesin complex has been shown to play a physical role in holding sister chromatids together, its loading onto chromatin is not sufficient for the establishment of sister chromatid cohesion. The activity of the cohesin complex must be turned on by Ctf7/Eco1 acetyltransferase at the replication forks as the result of a specific mechanism. To dissect this mechanism in the well established in vitro system based on the use of Xenopus egg extracts, we cloned two Xenopus orthologs of Ctf7/Eco1 acetyltransferase, XEco1 and XEco2. Both proteins share a domain structure with known members of Ctf7/Eco1 family proteins. Moreover, biochemical analysis showed that XEco2 exhibited acetyltransferase activity. We raised a specific antibody against XEco2 and used it to further characterize XEco2. In tissue culture cells, XEco2 gradually accumulated in nuclei through the S phase. In nuclei formed in egg extract, XEco2 was loaded into the chromatin at a constant level in a manner sensitive to geminin, an inhibitor of the pre-replication complex assembly, but insensitive to aphidicolin, an inhibitor of DNA polymerases. In both systems, no specific localization was observed during mitosis. In XEco2-depleted egg extracts, DNA replication occurred with normal kinetics and efficiency, and the condensation and sister chromatid cohesion of subsequently formed mitotic chromosomes was unaffected. These observations will serve as a platform for elucidating the molecular function of Ctf7/Eco1 acetyltransferase in the establishment of sister chromatid cohesion in future studies, in which XEco1 and XEco2 should be dissected in parallel.
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Affiliation(s)
- Masatoshi Takagi
- Cellular Dynamics Laboratory, RIKEN Advanced Science Institute, Saitama, Japan
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175
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Cohesin subunit SMC1 associates with mitotic microtubules at the spindle pole. Proc Natl Acad Sci U S A 2008; 105:15441-5. [PMID: 18832153 DOI: 10.1073/pnas.0807660105] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Accurate mitotic chromosome segregation depends on the formation of a microtubule-based bipolar spindle apparatus. We report that the cohesin subunit structural maintenance of chromosomes subunit 1 (SMC1) is recruited to microtubule-bound RNA export factor 1 (Rae1) at the mitotic spindle pole. We locate the Rae1-binding site to a 21-residue-long region, SMC1(947-967) and provide several lines of evidence that phosphorylation of Ser(957) and Ser(966) of SMC1 stimulates binding to Rae1. Imbalances in these assembly pathways caused formation of multipolar spindles. Our data suggest that cohesin's known bundling function for chromatids in mitotic and interphase cells extends to microtubules at the spindle pole.
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176
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Abstract
Cohesin is a large ring-shaped protein complex that mediates cohesion between sister chromatids. New experiments show that the sister chromatids of a minichromosome are entrapped by monomeric cohesin rings, thus excluding the possibility that sister chromatid cohesion is mediated by nontopological interactions between cohesin complexes.
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177
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Losada A. The regulation of sister chromatid cohesion. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1786:41-8. [PMID: 18474253 DOI: 10.1016/j.bbcan.2008.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 03/06/2008] [Accepted: 04/08/2008] [Indexed: 01/20/2023]
Abstract
Sister chromatid cohesion is a major feature of the eukaryotic chromosome. It entails the formation of a physical linkage between the two copies of a chromosome that result from the duplication process. This linkage must be maintained until chromosome segregation takes place in order to ensure the accurate distribution of the genomic information. Cohesin, a multiprotein complex conserved from yeast to humans, is largely responsible for sister chromatid cohesion. Other cohesion factors regulate the interaction of cohesin with chromatin as well as the establishment and dissolution of cohesion. In addition, the presence of cohesin throughout the genome appears to influence processes other than chromosome segregation, such as transcription and DNA repair. In this review I summarize recent advances in our understanding of cohesin function and regulation in mitosis, and discuss the consequences of impairing the cohesion process at the level of the whole organism.
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Affiliation(s)
- Ana Losada
- Chromosome Dynamics Group, Spanish National Cancer Research Centre, Melchor Fernández Almagro 3, Madrid E-28029, Spain.
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178
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McKee BD. Does cohesin regulate developmental gene expression in Drosophila? Proc Natl Acad Sci U S A 2008; 105:12097-8. [PMID: 18715997 PMCID: PMC2527870 DOI: 10.1073/pnas.0805712105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Bruce D McKee
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences Building, Knoxville, TN 37996-0840, USA.
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179
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Hallson G, Syrzycka M, Beck SA, Kennison JA, Dorsett D, Page SL, Hunter SM, Keall R, Warren WD, Brock HW, Sinclair DAR, Honda BM. The Drosophila cohesin subunit Rad21 is a trithorax group (trxG) protein. Proc Natl Acad Sci U S A 2008; 105:12405-10. [PMID: 18713858 PMCID: PMC2527924 DOI: 10.1073/pnas.0801698105] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Indexed: 12/19/2022] Open
Abstract
The cohesin complex is a key player in regulating cell division. Cohesin proteins SMC1, SMC3, Rad21, and stromalin (SA), along with associated proteins Nipped-B, Pds5, and EcoI, maintain sister chromatid cohesion before segregation to daughter cells during anaphase. Recent chromatin immunoprecipitation (ChIP) data reveal extensive overlap of Nipped-B and cohesin components with RNA polymerase II binding at active genes in Drosophila. These and other data strongly suggest a role for cohesion in transcription; however, there is no clear evidence for any specific mechanisms by which cohesin and associated proteins regulate transcription. We report here a link between cohesin components and trithorax group (trxG) function, thus implicating these proteins in transcription activation and/or elongation. We show that the Drosophila Rad21 protein is encoded by verthandi (vtd), a member of the trxG gene family that is also involved in regulating the hedgehog (hh) gene. In addition, mutations in the associated protein Nipped-B show similar trxG activity i.e., like vtd, they act as dominant suppressors of Pc and hh(Mrt) without impairing cell division. Our results provide a framework to further investigate how cohesin and associated components might regulate transcription.
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Affiliation(s)
- Graham Hallson
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - Monika Syrzycka
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - Samantha A. Beck
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - James A. Kennison
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2785
| | - Dale Dorsett
- Department of Biochemistry and Molecular Biology, School of Medicine, St. Louis University, St. Louis, MO 63104; and
| | - Scott L. Page
- Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia
| | - Sally M. Hunter
- Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia
| | - Rebecca Keall
- Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia
| | - William D. Warren
- Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia
| | - Hugh W. Brock
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Donald A. R. Sinclair
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
| | - Barry M. Honda
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A 1S6
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180
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McNairn AJ, Gerton JL. The chromosome glue gets a little stickier. Trends Genet 2008; 24:382-9. [PMID: 18602182 DOI: 10.1016/j.tig.2008.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 06/05/2008] [Accepted: 06/05/2008] [Indexed: 12/25/2022]
Abstract
Since their discovery, the cohesin proteins have been intensely studied in multiple model systems to determine the mechanism of chromosome cohesion. Recent studies have demonstrated that cohesin is much more than a molecular glue that holds chromosomes together in mitosis. Indeed, cohesin performs critical roles in gene regulation, possibly through the formation of higher-order chromatin structure. Moreover, this newly appreciated role is necessary for proper development in metazoan species, with mutations in the cohesin pathway resulting in human developmental disorders.
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Affiliation(s)
- Adrian J McNairn
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
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181
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Abstract
The cohesin complex is best known for its role in sister chromatid cohesion. Over the past few years, it has become apparent that cohesin also regulates gene expression, but the mechanisms by which it does so are unknown. Recently, three groups mapped numerous cohesin-binding sites in mammalian chromosomes and found substantial overlap with the CCCTC-binding factor (CTCF).1-3 CTCF is an insulator protein that blocks enhancer-promoter interactions, and the investigators found that cohesin also contributes to this activity. Thus, these studies demonstrate at least one mechanism by which cohesin can control gene expression.
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Affiliation(s)
- Maria Gause
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Missouri 63104, USA.
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182
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Haering CH, Farcas AM, Arumugam P, Metson J, Nasmyth K. The cohesin ring concatenates sister DNA molecules. Nature 2008; 454:297-301. [PMID: 18596691 DOI: 10.1038/nature07098] [Citation(s) in RCA: 380] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 05/15/2008] [Indexed: 12/31/2022]
Abstract
Sister chromatid cohesion, which is essential for mitosis, is mediated by a multi-subunit protein complex called cohesin. Cohesin's Scc1, Smc1 and Smc3 subunits form a tripartite ring structure, and it has been proposed that cohesin holds sister DNA molecules together by trapping them inside its ring. To test this, we used site-specific crosslinking to create chemical connections at the three interfaces between the three constituent polypeptides of the ring, thereby creating covalently closed cohesin rings. As predicted by the ring entrapment model, this procedure produced dimeric DNA-cohesin structures that are resistant to protein denaturation. We conclude that cohesin rings concatenate individual sister minichromosome DNA molecules.
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Affiliation(s)
- Christian H Haering
- University of Oxford, Department of Biochemistry, South Parks Road, Oxford OX1 3QU, UK
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183
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Cohesin branches out. Nat Rev Mol Cell Biol 2008. [DOI: 10.1038/nrm2371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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184
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Abstract
During cell division the cohesin complex mediates the pairing of sister chromatids. Emerging evidence shows that cohesin also has roles in interphase cells. New studies, including that of Gullerova and Proudfoot (2008) in this issue, reveal how cohesin is targeted to specific sites on chromosomes and implicate cohesin in the regulation of gene expression.
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Affiliation(s)
- Daniel Peric-Hupkes
- Division of Molecular Biology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
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185
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186
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Pauli A, Althoff F, Oliveira RA, Heidmann S, Schuldiner O, Lehner CF, Dickson BJ, Nasmyth K. Cell-type-specific TEV protease cleavage reveals cohesin functions in Drosophila neurons. Dev Cell 2008; 14:239-51. [PMID: 18267092 PMCID: PMC2258333 DOI: 10.1016/j.devcel.2007.12.009] [Citation(s) in RCA: 227] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 12/07/2007] [Accepted: 12/12/2007] [Indexed: 12/22/2022]
Abstract
Cohesin is a highly conserved multisubunit complex that holds sister chromatids together in mitotic cells. At the metaphase to anaphase transition, proteolytic cleavage of the alpha kleisin subunit (Rad21) by separase causes cohesin's dissociation from chromosomes and triggers sister-chromatid disjunction. To investigate cohesin's function in postmitotic cells, where it is widely expressed, we have created fruit flies whose Rad21 can be cleaved by TEV protease. Cleavage causes precocious separation of sister chromatids and massive chromosome missegregation in proliferating cells, but not disaggregation of polytene chromosomes in salivary glands. Crucially, cleavage in postmitotic neurons is lethal. In mushroom-body neurons, it causes defects in axon pruning, whereas in cholinergic neurons it causes highly abnormal larval locomotion. These data demonstrate essential roles for cohesin in nondividing cells and also introduce a powerful tool by which to investigate protein function in metazoa.
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Affiliation(s)
- Andrea Pauli
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | | | - Stefan Heidmann
- Department of Genetics, University of Bayreuth, 95440 Bayreuth, Germany
| | - Oren Schuldiner
- Stanford University, Department of Biological Sciences, Stanford, CA 94305, USA
| | | | | | - Kim Nasmyth
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
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187
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Abstract
The cohesin protein complex holds sister chromatids together to ensure proper chromosome segregation at mitosis in dividing cells. New experiments by two laboratories (reviewed in this issue of Developmental Cell) using different techniques reveal that cohesin also plays critical roles in morphogenesis of nondividing neurons. Other recent studies argue that these roles involve regulation of gene transcription.
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Affiliation(s)
- Dale Dorsett
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1100 South Grand Boulevard, Saint Louis, MO 63104, USA.
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