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Abstract
DNA sequencing has revolutionized medicine over recent decades. However, analysis of large structural variation and repetitive DNA, a hallmark of human genomes, has been limited by short-read technology, with read lengths of 100-300 bp. Long-read sequencing (LRS) permits routine sequencing of human DNA fragments tens to hundreds of kilobase pairs in size, using both real-time sequencing by synthesis and nanopore-based direct electronic sequencing. LRS permits analysis of large structural variation and haplotypic phasing in human genomes and has enabled the discovery and characterization of rare pathogenic structural variants and repeat expansions. It has also recently enabled the assembly of a complete, gapless human genome that includes previously intractable regions, such as highly repetitive centromeres and homologous acrocentric short arms. With the addition of protocols for targeted enrichment, direct epigenetic DNA modification detection, and long-range chromatin profiling, LRS promises to launch a new era of understanding of genetic diversity and pathogenic mutations in human populations.
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Affiliation(s)
- Peter E Warburton
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; ,
- Center for Advanced Genomics Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Robert P Sebra
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; ,
- Center for Advanced Genomics Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Icahn Genomics Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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2
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Tenney AP, Di Gioia SA, Webb BD, Chan WM, de Boer E, Garnai SJ, Barry BJ, Ray T, Kosicki M, Robson CD, Zhang Z, Collins TE, Gelber A, Pratt BM, Fujiwara Y, Varshney A, Lek M, Warburton PE, Van Ryzin C, Lehky TJ, Zalewski C, King KA, Brewer CC, Thurm A, Snow J, Facio FM, Narisu N, Bonnycastle LL, Swift A, Chines PS, Bell JL, Mohan S, Whitman MC, Staffieri SE, Elder JE, Demer JL, Torres A, Rachid E, Al-Haddad C, Boustany RM, Mackey DA, Brady AF, Fenollar-Cortés M, Fradin M, Kleefstra T, Padberg GW, Raskin S, Sato MT, Orkin SH, Parker SCJ, Hadlock TA, Vissers LELM, van Bokhoven H, Jabs EW, Collins FS, Pennacchio LA, Manoli I, Engle EC. Noncoding variants alter GATA2 expression in rhombomere 4 motor neurons and cause dominant hereditary congenital facial paresis. Nat Genet 2023; 55:1149-1163. [PMID: 37386251 PMCID: PMC10335940 DOI: 10.1038/s41588-023-01424-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/10/2023] [Indexed: 07/01/2023]
Abstract
Hereditary congenital facial paresis type 1 (HCFP1) is an autosomal dominant disorder of absent or limited facial movement that maps to chromosome 3q21-q22 and is hypothesized to result from facial branchial motor neuron (FBMN) maldevelopment. In the present study, we report that HCFP1 results from heterozygous duplications within a neuron-specific GATA2 regulatory region that includes two enhancers and one silencer, and from noncoding single-nucleotide variants (SNVs) within the silencer. Some SNVs impair binding of NR2F1 to the silencer in vitro and in vivo and attenuate in vivo enhancer reporter expression in FBMNs. Gata2 and its effector Gata3 are essential for inner-ear efferent neuron (IEE) but not FBMN development. A humanized HCFP1 mouse model extends Gata2 expression, favors the formation of IEEs over FBMNs and is rescued by conditional loss of Gata3. These findings highlight the importance of temporal gene regulation in development and of noncoding variation in rare mendelian disease.
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Affiliation(s)
- Alan P Tenney
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Silvio Alessandro Di Gioia
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
- Regeneron Pharmaceuticals, Tarrytown, NY, USA
| | - Bryn D Webb
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Wai-Man Chan
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Elke de Boer
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Sarah J Garnai
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Harvard-MIT Health Sciences and Technology, Harvard Medical School, Boston, MA, USA
| | - Brenda J Barry
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Tammy Ray
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael Kosicki
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Caroline D Robson
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Zhongyang Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Thomas E Collins
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alon Gelber
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Brandon M Pratt
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Yuko Fujiwara
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, MA, USA
| | - Arushi Varshney
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Monkol Lek
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Peter E Warburton
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Center for Advanced Genomics Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Carol Van Ryzin
- Metabolic Medicine Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Tanya J Lehky
- EMG Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Christopher Zalewski
- Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, USA
| | - Kelly A King
- Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, USA
| | - Carmen C Brewer
- Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, USA
| | - Audrey Thurm
- Neurodevelopmental and Behavioral Phenotyping Service, National Institute of Mental Health, NIH, Bethesda, MD, USA
| | - Joseph Snow
- Office of the Clinical Director, National Institute of Mental Health, NIH, Bethesda, MD, USA
| | - Flavia M Facio
- Center for Precision Health Research, National Human Genome Research Institute, NIH, Bethesda, MD, USA
- Invitae Corporation, San Francisco, CA, USA
| | - Narisu Narisu
- Center for Precision Health Research, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Lori L Bonnycastle
- Center for Precision Health Research, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Amy Swift
- Center for Precision Health Research, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Peter S Chines
- Center for Precision Health Research, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Jessica L Bell
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Suresh Mohan
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Mary C Whitman
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sandra E Staffieri
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, and University of Melbourne, Melbourne, Victoria, Australia
- Department of Ophthalmology, Royal Children's Hospital, Parkville, Victoria, Australia
| | - James E Elder
- Department of Ophthalmology, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Joseph L Demer
- Stein Eye Institute and Departments of Ophthalmology, Neurology, and Bioengineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Alcy Torres
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Pediatrics, Boston Medical Center, Boston University Aram V. Chobanian & Edward Avedisian School of Medicine, Boston, MA, USA
| | - Elza Rachid
- Department of Ophthalmology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Christiane Al-Haddad
- Department of Ophthalmology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Rose-Mary Boustany
- Pediatrics & Adolescent Medicine/Biochemistry & Molecular Genetics, American University of Beirut Medical Center, Beirut, Lebanon
| | - David A Mackey
- Lions Eye Institute, University of Western Australia, Perth, Australia
| | - Angela F Brady
- North West Thames Regional Genetics Service, Northwick Park Hospital, Harrow, UK
| | - María Fenollar-Cortés
- Unidad de Genética Clínica, Instituto de Medicina del Laboratorio. IdISSC, Hospital Clínico San Carlos, Madrid, Spain
| | - Melanie Fradin
- Service de Génétique Clinique, CHU Rennes, Centre Labellisé Anomalies du Développement, Rennes, France
| | - Tjitske Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Center of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, Venray, the Netherlands
| | - George W Padberg
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Salmo Raskin
- Centro de Aconselhamento e Laboratório Genetika, Curitiba, Paraná, Brazil
| | - Mario Teruo Sato
- Department of Ophthalmology & Otorhinolaryngology, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Stuart H Orkin
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, MA, USA
| | - Stephen C J Parker
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Tessa A Hadlock
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Lisenka E L M Vissers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ethylin Wang Jabs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Francis S Collins
- Center for Precision Health Research, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Len A Pennacchio
- Environmental Genomics & System Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Irini Manoli
- Metabolic Medicine Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Elizabeth C Engle
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, USA.
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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Hasson D, Panchenko T, Salimian KJ, Salman MU, Sekulic N, Alonso A, Warburton PE, Black BE. The octamer is the major form of CENP-A nucleosomes at human centromeres. Nat Struct Mol Biol 2013; 20:687-95. [PMID: 23644596 PMCID: PMC3760417 DOI: 10.1038/nsmb.2562] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 03/07/2013] [Indexed: 12/27/2022]
Abstract
The centromere is the chromosomal locus that ensures fidelity in genome transmission at cell division. Centromere protein A (CENP-A) is a histone H3 variant that specifies centromere location independently of DNA sequence. Conflicting evidence has emerged regarding the histone composition and stoichiometry of CENP-A nucleosomes. Here we show that the predominant form of the CENP-A particle at human centromeres is an octameric nucleosome. CENP-A nucleosomes are very highly phased on α-satellite 171 bp monomers at normal centromeres, and also display strong positioning at neocentromeres. At either type of functional centromere, CENP-A nucleosomes exhibit similar DNA wrapping behavior as octameric CENP-A nucleosomes reconstituted with recombinant components, having looser DNA termini than those on their conventional counterparts containing canonical H3. Thus, the fundamental unit of the chromatin that epigenetically specifies centromere location in mammals is an octameric nucleosome with loose termini.
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Affiliation(s)
- Dan Hasson
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Panchenko T, Salimian KJ, Hasson D, Salman MU, Warburton PE, Black BE. CENP-A at Human Centromeres and Neocentromeres Forms Octameric Nucleosomes with Loose Superhelical Termini. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.3211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Hemmat M, Wang BT, Warburton PE, Yang X, Boyar FZ, El Naggar M, Anguiano A. Neocentric X-chromosome in a girl with Turner-like syndrome. Mol Cytogenet 2012; 5:29. [PMID: 22682421 PMCID: PMC3477003 DOI: 10.1186/1755-8166-5-29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 04/11/2012] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Neocentromeres are rare human chromosomal aberrations in which a new centromere has formed in a previously non-centromeric location. We report the finding of a structurally abnormal X chromosome with a neocentromere in a 15-year-old girl with clinical features suggestive of Turner syndrome, including short stature and primary amenorrhea. RESULT G-banded chromosome analysis revealed a mosaic female karyotype involving two abnormal cell lines. One cell line (84% of analyzed metaphases) had a structurally abnormal X chromosome (duplication of the long arm and deletion of the short arm) and a normal X chromosome. The other cell line (16% of cells) exhibited monosomy X. C-banding studies were negative for the abnormal X chromosome. FISH analysis revealed lack of hybridization of the abnormal X chromosome with both the X centromere-specific probe and the "all human centromeres" probe, a pattern consistent with lack of the X chromosome endogenous centromere. A FISH study using an XIST gene probe revealed the presence of two XIST genes, one on each long arm of the iso(Xq), required for inactivation of the abnormal X chromosome. R-banding also demonstrated inactivation of the abnormal X chromosome. An assay for centromeric protein C (CENP-C) was positive on both the normal and the abnormal X chromosomes. The position of CENP-C in the abnormal X chromosome defined a neocentromere, which explains its mitotic stability. The karyotype is thus designated as 46,X,neo(X)(qter- > q12::q12- > q21.2- > neo- > q21.2- > qter)[42]/45,X[8], which is consistent with stigmata of Turner syndrome. The mother of this patient has a normal karyotype; however, the father was not available for study. CONCLUSION To our knowledge, this is the first case of mosaic Turner syndrome involving an analphoid iso(Xq) chromosome with a proven neocentromere among 90 previously described cases with a proven neocentromere.
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Affiliation(s)
- Morteza Hemmat
- Cytogenetics Dept, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Boris T Wang
- Cytogenetics Dept, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Peter E Warburton
- Deparment of Genetics and Genomic Sciences, Mount Sinai School of Medicine, NY, USA
| | - Xiaojing Yang
- Cytogenetics Dept, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Fatih Z Boyar
- Cytogenetics Dept, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Mohammed El Naggar
- Cytogenetics Dept, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Arturo Anguiano
- Cytogenetics Dept, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA.,Quest Diagnostics Nichols Institute, 33608 Ortega Highway, San Juan Capistrano, CA, 92690, USA
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Jobanputra V, Burke A, Kwame AY, Shanmugham A, Shirazi M, Brown S, Warburton PE, Levy B, Warburton D. Duplication of the ZIC2 gene is not associated with holoprosencephaly. Am J Med Genet A 2011; 158A:103-8. [PMID: 22105922 DOI: 10.1002/ajmg.a.34375] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 10/17/2011] [Indexed: 11/12/2022]
Abstract
Cytogenetic testing using genomic microarrays presents a clinical challenge when data regarding the phenotypic consequences of the genomic alteration are not available. We describe a chromosome 13q32.3 duplication discovered by microarray testing in a fetus with a prenatally detected apparently balanced de novo translocation 46,XY,t(2;13)(q37;q32). Microarray analysis on the fetal DNA showed duplications of 384 and 564 kb at the breakpoint regions on chromosomes 2q37.3 and 13q32.3, respectively. There were no disease-associated genes in the duplicated region on chromosome 2q37. The duplicated region on chromosome 13q contains the ZIC2 gene. Haploinsufficiency of ZIC2 is known to cause holoprosencephaly and other brain malformations. Studies in the mouse models have suggested that over expression of ZIC2 may also lead to brain malformations. Fetal MRI of the brain was normal and the family elected to continue the pregnancy. An apparently normal baby was born at term. At 3 months of age a physical exam showed no abnormalities and no developmental delay. This report shows that duplication of ZIC2 is not necessarily associated with brain malformations. We also describe the phenotype from four additional patients with duplications of the region of chromosome 13 containing ZIC2 and three previously described patients with supernumerary marker chromosomes derived from distal chromosome 13. None of the eight patients had holoprosencephaly or brain malformations, indicating that duplication of ZIC2 is not associated with brain anomalies. This information will be useful for counseling in other occurrences of this duplication identified by microarray.
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Affiliation(s)
- Vaidehi Jobanputra
- Department of Pathology, Columbia University Medical Center, New York, New York, USA.
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Hasson D, Alonso A, Cheung F, Tepperberg JH, Papenhausen PR, Engelen JJM, Warburton PE. Formation of novel CENP-A domains on tandem repetitive DNA and across chromosome breakpoints on human chromosome 8q21 neocentromeres. Chromosoma 2011; 120:621-32. [PMID: 21826412 DOI: 10.1007/s00412-011-0337-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 07/21/2011] [Accepted: 07/25/2011] [Indexed: 01/02/2023]
Abstract
Endogenous human centromeres form on megabase-sized arrays of tandemly repeated alpha satellite DNA. Human neocentromeres form epigenetically at ectopic sites devoid of alpha satellite DNA and permit analysis of centromeric DNA and chromatin organization. In this study, we present molecular cytogenetic and CENP-A chromatin immunoprecipitation (ChIP) on CHIP analyses of two neocentromeres that have formed in chromosome band 8q21 each with a unique DNA and CENP-A chromatin configuration. The first neocentromere was found on a neodicentric chromosome 8 with an inactivated endogenous centromere, where the centromeric activity and CENP-A domain were repositioned to band 8q21 on a large tandemly repeated DNA. This is the first example of a neocentromere forming on repetitive DNA, as all other mapped neocentromeres have formed on single copy DNA. Quantitative fluorescent in situ hybridization (FISH) analysis showed a 60% reduction in the alpha satellite array size at the inactive centromere compared to the active centromere on the normal chromosome 8. This neodicentric chromosome may provide insight into centromere inactivation and the role of tandem DNA in centromere structure. The second neocentromere was found on a neocentric ring chromosome that contained the 8q21 tandemly repeated DNA, although the neocentromere was localized to a different genomic region. Interestingly, this neocentromere is composed of two distinct CENP-A domains in bands 8q21 and 8q24, which are brought into closer proximity on the ring chromosome. This neocentromere suggests that chromosomal rearrangement and DNA breakage may be involved in neocentromere formation. These novel examples provide insight into the formation and structure of human neocentromeres.
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Affiliation(s)
- Dan Hasson
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, Icahn Medical Institute, NY 10029, USA
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8
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Burnside RD, Ibrahim J, Flora C, Schwartz S, Tepperberg JH, Papenhausen PR, Warburton PE. Interstitial deletion of proximal 8q including part of the centromere from unbalanced segregation of a paternal deletion/marker karyotype with neocentromere formation at 8p22. Cytogenet Genome Res 2011; 132:227-32. [PMID: 21212645 DOI: 10.1159/000322815] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The 'McClintock mechanism' of chromosome breakage and centromere misdivision, in which a deleted chromosome with its concomitant excised marker or ring chromosome is formed, has been described in approximately one dozen reports. We report a case of a girl with short stature, developmental delay, and dysmorphic features. METHODS Analysis was performed on the proband and father using cytogenetic chromosome analysis and the Affymetrix 6.0 SNP microarray. Fluorescence in situ hybridization (FISH) using a chromosome 8 alpha-satellite probe and immunofluorescence with antibodies to CENP-C were used to examine the centromere positions in these chromosomes. RESULTS An abnormal chromosome 8 with a cytogenetically visible deletion was further defined by SNP array as a 10.6-Mb deletion from 8q11.1→q12.1. FISH with a chromosome 8 alpha-satellite probe demonstrated that the deletion removed a significant portion of the pericentromeric alpha-satellite repeat sequences and proximal q arm. The deleted chromosome 8 appeared to have a constriction at 8p22, suggesting the formation of a neocentromere, even though alpha-satellite sequences still appeared at the normal location. Chromosome analysis of the phenotypically normal father revealed the same deleted chromosome 8, as well as an apparently balancing mosaic marker chromosome 8. FISH studies revealed that the majority of the chromosome 8 alpha-satellite DNA resided in the marker chromosome. Immunofluorescence studies with antibodies to CENP-C, a kinetochore protein, proved the presence of a neocentromere at 8p22. The excision of the marker from the deleted chromosome 8 likely necessitated the formation of a new kinetochore at the 8p22 neocentromere to stabilize the chromosome during mitosis. CONCLUSION This case clearly illustrates the utilization of classic cytogenetics, FISH, and array technologies to better characterize chromosomal abnormalities and provide information on recurrence risks. It also represents a rare case where a neocentromere can form even in the presence of existing alpha-satellite DNA.
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Affiliation(s)
- R D Burnside
- Laboratory Corporation of America, Research Triangle Park, NC 27709, USA.
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9
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Scott SA, Cohen N, Brandt T, Warburton PE, Edelmann L. Large inverted repeats within Xp11.2 are present at the breakpoints of isodicentric X chromosomes in Turner syndrome. Hum Mol Genet 2010; 19:3383-93. [PMID: 20570968 PMCID: PMC2916707 DOI: 10.1093/hmg/ddq250] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 06/03/2010] [Accepted: 06/14/2010] [Indexed: 02/01/2023] Open
Abstract
Turner syndrome (TS) results from whole or partial monosomy X and is mediated by haploinsufficiency of genes that normally escape X-inactivation. Although a 45,X karyotype is observed in half of all TS cases, the most frequent variant TS karyotype includes the isodicentric X chromosome alone [46,X,idic(X)(p11)] or as a mosaic [46,X,idic(X)(p11)/45,X]. Given the mechanism of idic(X)(p11) rearrangement is poorly understood and breakpoint sequence information is unknown, this study sought to investigate the molecular mechanism of idic(X)(p11) formation by determining their precise breakpoint intervals. Karyotype analysis and fluorescence in situ hybridization mapping of eight idic(X)(p11) cell lines and three unbalanced Xp11.2 translocation lines identified the majority of breakpoints within a 5 Mb region, from approximately 53 to 58 Mb, in Xp11.1-p11.22, clustering into four regions. To further refine the breakpoints, a high-resolution oligonucleotide microarray (average of approximately 350 bp) was designed and array-based comparative genomic hybridization (aCGH) was performed on all 11 idic(X)(p11) and Xp11.2 translocation lines. aCGH analyses identified all breakpoint regions, including an idic(X)(p11) line with two potential breakpoints, one breakpoint shared between two idic(X)(p11) lines and two Xp translocations that shared breakpoints with idic(X)(p11) lines. Four of the breakpoint regions included large inverted repeats composed of repetitive gene clusters and segmental duplications, which corresponded to regions of copy-number variation. These data indicate that the rearrangement sites on Xp11.2 that lead to isodicentric chromosome formation and translocations are probably not random and suggest that the complex repetitive architecture of this region predisposes it to rearrangements, some of which are recurrent.
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Affiliation(s)
| | | | | | | | - Lisa Edelmann
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine of New York University, New York 10029, USA
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10
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Alonso A, Hasson D, Cheung F, Warburton PE. A paucity of heterochromatin at functional human neocentromeres. Epigenetics Chromatin 2010; 3:6. [PMID: 20210998 PMCID: PMC2845132 DOI: 10.1186/1756-8935-3-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 03/08/2010] [Indexed: 12/29/2022] Open
Abstract
Background Centromeres are responsible for the proper segregation of replicated chromatids during cell division. Neocentromeres are fully functional ectopic human centromeres that form on low-copy DNA sequences and permit analysis of centromere structure in relation to the underlying DNA sequence. Such structural analysis is not possible at endogenous centromeres because of the large amounts of repetitive alpha satellite DNA present. Results High-resolution chromatin immunoprecipitation (ChIP) on CHIP (microarray) analysis of three independent neocentromeres from chromosome 13q revealed that each neocentromere contained ~100 kb of centromere protein (CENP)-A in a two-domain organization. Additional CENP-A domains were observed in the vicinity of neocentromeres, coinciding with CpG islands at the 5' end of genes. Analysis of histone H3 dimethylated at lysine 4 (H3K4me2) revealed small domains at each neocentromere. However, these domains of H3K4me2 were also found in the equivalent non-neocentric chromosomes. A surprisingly minimal (~15 kb) heterochromatin domain was observed at one of the neocentromeres, which formed in an unusual transposon-free region distal to the CENP-A domains. Another neocentromere showed a distinct absence of nearby significant domains of heterochromatin. A subtle defect in centromere cohesion detected at these neocentromeres may be due to the paucity of heterochromatin domains. Conclusions This high-resolution mapping suggests that H3K4me2 does not seem sufficiently abundant to play a structural role at neocentromeres, as proposed for endogenous centromeres. Large domains of heterochromatin also do not appear necessary for centromere function. Thus, this study provides important insight into the structural requirements of human centromere function.
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Affiliation(s)
- Alicia Alonso
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, NY 10029, USA
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Warburton PE, Hasson D, Guillem F, Lescale C, Jin X, Abrusan G. Analysis of the largest tandemly repeated DNA families in the human genome. BMC Genomics 2008; 9:533. [PMID: 18992157 PMCID: PMC2588610 DOI: 10.1186/1471-2164-9-533] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 11/07/2008] [Indexed: 01/26/2023] Open
Abstract
Background Tandemly Repeated DNA represents a large portion of the human genome, and accounts for a significant amount of copy number variation. Here we present a genome wide analysis of the largest tandem repeats found in the human genome sequence. Results Using Tandem Repeats Finder (TRF), tandem repeat arrays greater than 10 kb in total size were identified, and classified into simple sequence e.g. GAATG, classical satellites e.g. alpha satellite DNA, and locus specific VNTR arrays. Analysis of these large sequenced regions revealed that several "simple sequence" arrays actually showed complex domain and/or higher order repeat organization. Using additional methods, we further identified a total of 96 additional arrays with tandem repeat units greater than 2 kb (the detection limit of TRF), 53 of which contained genes or repeated exons. The overall size of an array of tandem 12 kb repeats which spanned a gap on chromosome 8 was found to be 600 kb to 1.7 Mbp in size, representing one of the largest non-centromeric arrays characterized. Several novel megasatellite tandem DNA families were observed that are characterized by repeating patterns of interspersed transposable elements that have expanded presumably by unequal crossing over. One of these families is found on 11 different chromosomes in >25 arrays, and represents one of the largest most widespread megasatellite DNA families. Conclusion This study represents the most comprehensive genome wide analysis of large tandem repeats in the human genome, and will serve as an important resource towards understanding the organization and copy number variation of these complex DNA families.
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Affiliation(s)
- Peter E Warburton
- Deptartment of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Giordano J, Ge Y, Gelfand Y, Abrusán G, Benson G, Warburton PE. Evolutionary history of mammalian transposons determined by genome-wide defragmentation. PLoS Comput Biol 2008; 3:e137. [PMID: 17630829 PMCID: PMC1914374 DOI: 10.1371/journal.pcbi.0030137] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Accepted: 05/31/2007] [Indexed: 01/30/2023] Open
Abstract
The constant bombardment of mammalian genomes by transposable elements (TEs) has resulted in TEs comprising at least 45% of the human genome. Because of their great age and abundance, TEs are important in comparative phylogenomics. However, estimates of TE age were previously based on divergence from derived consensus sequences or phylogenetic analysis, which can be unreliable, especially for older more diverged elements. Therefore, a novel genome-wide analysis of TE organization and fragmentation was performed to estimate TE age independently of sequence composition and divergence or the assumption of a constant molecular clock. Analysis of TEs in the human genome revealed ∼600,000 examples where TEs have transposed into and fragmented other TEs, covering >40% of all TEs or ∼542 Mbp of genomic sequence. The relative age of these TEs over evolutionary time is implicit in their organization, because newer TEs have necessarily transposed into older TEs that were already present. A matrix of the number of times that each TE has transposed into every other TE was constructed, and a novel objective function was developed that derived the chronological order and relative ages of human TEs spanning >100 million years. This method has been used to infer the relative ages across all four major TE classes, including the oldest, most diverged elements. Analysis of DNA transposons over the history of the human genome has revealed the early activity of some MER2 transposons, and the relatively recent activity of MER1 transposons during primate lineages. The TEs from six additional mammalian genomes were defragmented and analyzed. Pairwise comparison of the independent chronological orders of TEs in these mammalian genomes revealed species phylogeny, the fact that transposons shared between genomes are older than species-specific transposons, and a subset of TEs that were potentially active during periods of speciation. Transposable elements (TEs) are interspersed repetitive DNA families that are capable of copying themselves from place to place; they have literally infested our genome over evolutionary time, and now comprise as much as 45% of our total DNA. Because of their great age and abundance, TEs are important in evolutionary genomics. However, estimates of their age based on DNA sequence composition have been unreliable, especially for older more diverged elements. Therefore, a novel method to estimate the age of TEs was developed based on the fact that as TEs spread throughout the genome, they inserted into and fragmented older TEs that were already present. Therefore, the age of TEs can be revealed by how often they have been fragmented over evolutionary time. We performed a genome-wide defragmention of TEs, and developed a novel objective function to derive the chronological order of TEs spanning >100 million years. This method has been used to infer the relative ages of TEs from seven sequenced mammalian genomes across all four major TE classes, including the oldest, most diverged elements. This age estimate is independent of TE sequence composition or divergence and does not rely on the assumption of a constant molecular clock. This study provides a novel analysis of the evolutionary history of some of the most abundant and ancient repetitive DNA elements in mammalian genomes, which is important for understanding the dynamic forces that shape our genomes during evolution.
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Affiliation(s)
- Joti Giordano
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Yongchao Ge
- Department of Neurology, Mount Sinai School of Medicine, New York, New York, United States of America
- Center for Translational Systems Biology, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Yevgeniy Gelfand
- Laboratory for Biocomputing and Informatics, Boston University, Boston, Massachusetts, United States of America
| | - György Abrusán
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Gary Benson
- Departments of Computer Science and Biology, Boston University, Boston, Massachusetts, United States of America
| | - Peter E Warburton
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
- * To whom correspondence should be addressed. E-mail:
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Yu S, Barbouth D, Benke PJ, Warburton PE, Fan YS. Characterization of a neocentric supernumerary marker chromosome originating from the Xp distal region by FISH, CENP-C staining, and array CGH. Cytogenet Genome Res 2007; 116:141-5. [PMID: 17268194 DOI: 10.1159/000097434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 06/12/2006] [Indexed: 11/19/2022] Open
Abstract
A small supernumerary marker chromosome (SMC) was observed in a girl with severe developmental delay. Her dysmorphism included prominent forehead, hypertelorism, down-slanting palpebral fissures, low-set/large ears, and flat nasal bridge with anteverted nares. This case also presented hypotonia, hypermobility of joints, congenital heart defect, umbilical hernia, failure to thrive, and seizures. The SMC originated from the distal region of Xp as identified by FISH with multiple DNA probes. Staining with antibodies to Centromere Protein C (CENP-C) demonstrated a neocentromere, while FISH with an alpha-satellite DNA probe showed no hybridization to the SMC. A karyotype was described as 47,XX,+neo(X)(pter-->p22.31::p22.31-->pter), indicating a partial tetrasomy of Xp22.31-->pter. This karyotype represents a functional trisomy for Xp22.31-->pter and a functional tetrasomy for the pseudoautosomal region given that there is no X-inactivation center in the marker chromosome. The SMC was further characterized by microarray-based comparative genomic hybridization (array CGH) as a duplicated DNA fragment of approximately 13 megabase pairs containing about 100 genes. We have described here a new neocentromere with discussion of its clinical significance.
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Affiliation(s)
- S Yu
- Dr. John T. Macdonald Foundation Center for Medical Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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15
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Alonso A, Fritz B, Hasson D, Abrusan G, Cheung F, Yoda K, Radlwimmer B, Ladurner AG, Warburton PE. Co-localization of CENP-C and CENP-H to discontinuous domains of CENP-A chromatin at human neocentromeres. Genome Biol 2007; 8:R148. [PMID: 17651496 PMCID: PMC2323242 DOI: 10.1186/gb-2007-8-7-r148] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 06/28/2007] [Accepted: 07/25/2007] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Mammalian centromere formation is dependent on chromatin that contains centromere protein (CENP)-A, which is the centromere-specific histone H3 variant. Human neocentromeres have acquired CENP-A chromatin epigenetically in ectopic chromosomal locations on low-copy complex DNA. Neocentromeres permit detailed investigation of centromeric chromatin organization that is not possible in the highly repetitive alpha satellite DNA present at endogenous centromeres. RESULTS We have examined the distribution of CENP-A, as well as two additional centromeric chromatin-associated proteins (CENP-C and CENP-H), across neocentromeric DNA using chromatin immunoprecipitation (ChIP) on CHIP assays on custom genomic microarrays at three different resolutions. Analysis of two neocentromeres using a contiguous bacterial artificial chromosome (BAC) microarray spanning bands 13q31.3 to 13q33.1 shows that both CENP-C and CENP-H co-localize to the CENP-A chromatin domain. Using a higher resolution polymerase chain reaction (PCR)-amplicon microarray spanning the neocentromere, we find that the CENP-A chromatin is discontinuous, consisting of a major domain of about 87.8 kilobases (kb) and a minor domain of about 13.2 kb, separated by an approximately 158 kb region devoid of CENPs. Both CENP-A domains exhibit co-localization of CENP-C and CENP-H, defining a distinct inner kinetochore chromatin structure that is consistent with higher order chromatin looping models at centromeres. The PCR microarray data suggested varying density of CENP-A nucleosomes across the major domain, which was confirmed using a higher resolution oligo-based microarray. CONCLUSION Centromeric chromatin consists of several CENP-A subdomains with highly discontinuous CENP-A chromatin at both the level of individual nucleosomes and at higher order chromatin levels, raising questions regarding the overall structure of centromeric chromatin.
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Affiliation(s)
- Alicia Alonso
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, New York 10029, USA
| | - Björn Fritz
- Gene Expression Unit, Meyerhofstrasse, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
- Abbott Germany, Max-Planck-Ring, 65205 Wiesbaden, Germany
| | - Dan Hasson
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, New York 10029, USA
| | - György Abrusan
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, New York 10029, USA
| | - Fanny Cheung
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, New York 10029, USA
| | - Kinya Yoda
- Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Bernhard Radlwimmer
- Deutsches Krebsforschungszentrum (DKFZ), Im Neuenheimer Feld, 69120 Heidelberg, Germany
| | - Andreas G Ladurner
- Gene Expression Unit, Meyerhofstrasse, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Peter E Warburton
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, New York 10029, USA
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Cardone MF, Alonso A, Pazienza M, Ventura M, Montemurro G, Carbone L, de Jong PJ, Stanyon R, D'Addabbo P, Archidiacono N, She X, Eichler EE, Warburton PE, Rocchi M. Independent centromere formation in a capricious, gene-free domain of chromosome 13q21 in Old World monkeys and pigs. Genome Biol 2006; 7:R91. [PMID: 17040560 PMCID: PMC1794570 DOI: 10.1186/gb-2006-7-10-r91] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 07/31/2006] [Accepted: 10/13/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Evolutionary centromere repositioning and human analphoid neocentromeres occurring in clinical cases are, very likely, two stages of the same phenomenon whose properties still remain substantially obscure. Chromosome 13 is the chromosome with the highest number of neocentromeres. We reconstructed the mammalian evolutionary history of this chromosome and characterized two human neocentromeres at 13q21, in search of information that could improve our understanding of the relationship between evolutionarily new centromeres, inactivated centromeres, and clinical neocentromeres. RESULTS Chromosome 13 evolution was studied, using FISH experiments, across several diverse superordinal phylogenetic clades spanning >100 million years of evolution. The analysis revealed exceptional conservation among primates (hominoids, Old World monkeys, and New World monkeys), Carnivora (cat), Perissodactyla (horse), and Cetartiodactyla (pig). In contrast, the centromeres in both Old World monkeys and pig have apparently repositioned independently to a central location (13q21). We compared these results to the positions of two human 13q21 neocentromeres using chromatin immunoprecipitation and genomic microarrays. CONCLUSION We show that a gene-desert region at 13q21 of approximately 3.9 Mb in size possesses an inherent potential to form evolutionarily new centromeres over, at least, approximately 95 million years of mammalian evolution. The striking absence of genes may represent an important property, making the region tolerant to the extensive pericentromeric reshuffling during subsequent evolution. Comparison of the pericentromeric organization of chromosome 13 in four Old World monkey species revealed many differences in sequence organization. The region contains clusters of duplicons showing peculiar features.
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Affiliation(s)
| | - Alicia Alonso
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, USA
| | - Michele Pazienza
- Department of Genetics and Microbiology, University of Bari, Bari, Italy
| | - Mario Ventura
- Department of Genetics and Microbiology, University of Bari, Bari, Italy
| | | | - Lucia Carbone
- Department of Genetics and Microbiology, University of Bari, Bari, Italy
| | - Pieter J de Jong
- Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
| | - Roscoe Stanyon
- Department of Animal Biology and Genetics 'Leo Pardi', University of Florence, Florence, Italy
| | - Pietro D'Addabbo
- Department of Genetics and Microbiology, University of Bari, Bari, Italy
| | | | - Xinwei She
- Howard Hughes Medical Institute, Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195, USA
| | - Evan E Eichler
- Howard Hughes Medical Institute, Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195, USA
| | - Peter E Warburton
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, USA
| | - Mariano Rocchi
- Department of Genetics and Microbiology, University of Bari, Bari, Italy
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Abstract
Neocentromeres are rare human chromosomal aberrations where a new centromere has formed in a previously non-centromeric location. The emergence of new centromeres on a chromosome that already contains an endogenous centromere would be a highly deleterious event which would lead to dicentricity and mitotic instability. Nonetheless, neocentromere formation appears to provide a mechanism for the acquisition of a new centromere. Neocentromeres are most often observed on chromosomal arm fragments that have separated from an endogenous centromere, and therefore actually lead to mitotic stability of what would have been an acentric fragment. Neocentromeres have recently also been observed on apparently unrearranged chromosomes where the endogenous centromere has been inactivated. Furthermore, the process of centromere repositioning during primate chromosomal evolution may depend on the acquisition and subsequent fixation of neocentromeres. This remarkable plasticity in the position of centromeres has important implications for human cytogenetics and chromosome evolution, and provides an opportunity to further our understanding of the process of centromere formation and structure.
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Affiliation(s)
- Peter E Warburton
- Dept. of Human Genetics, Box 1498, Mount Sinai School of Medicine, 1425 Madison Ave, East Bldg 14-52A, New York, NY 10029, USA.
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Warburton PE, Giordano J, Cheung F, Gelfand Y, Benson G. Inverted repeat structure of the human genome: the X-chromosome contains a preponderance of large, highly homologous inverted repeats that contain testes genes. Genome Res 2004; 14:1861-9. [PMID: 15466286 PMCID: PMC524409 DOI: 10.1101/gr.2542904] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We have performed the first genome-wide analysis of the Inverted Repeat (IR) structure in the human genome, using a novel and efficient software package called Inverted Repeats Finder (IRF). After masking of known repetitive elements, IRF detected 22,624 human IRs characterized by arm size from 25 bp to >100 kb with at least 75% identity, and spacer length up to 100 kb. This analysis required 6 h on a desktop PC. In all, 166 IRs had arm lengths >8 kb. From this set, IRs were excluded if they were in unfinished/unassembled regions of the genome, or clustered with other closely related IRs, yielding a set of 96 large IRs. Of these, 24 (25%) occurred on the X-chromosome, although it represents only approximately 5% of the genome. Of the X-chromosome IRs, 83.3% were >/=99% identical, compared with 28.8% of autosomal IRs. Eleven IRs from Chromosome X, one from Chromosome 11, and seven already described from Chromosome Y contain genes predominantly expressed in testis. PCR analysis of eight of these IRs correctly amplified the corresponding region in the human genome, and six were also confirmed in gorilla or chimpanzee genomes. Similarity dot-plots revealed that 22 IRs contained further secondary homologous structures partially categorized into three distinct patterns. The prevalence of large highly homologous IRs containing testes genes on the X- and Y-chromosomes suggests a possible role in male germ-line gene expression and/or maintaining sequence integrity by gene conversion.
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Affiliation(s)
- Peter E Warburton
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Alonso A, Mahmood R, Li S, Cheung F, Yoda K, Warburton PE. Genomic microarray analysis reveals distinct locations for the CENP-A binding domains in three human chromosome 13q32 neocentromeres. Hum Mol Genet 2003; 12:2711-21. [PMID: 12928482 DOI: 10.1093/hmg/ddg282] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human neocentromeres are fully functional centromeres that provide mitotic stability to rearranged chromosomes that have separated from endogenous centromeres. A disproportionate number of neocentromeres has been observed in certain regions such as chromosome 3q (n=6), 15q (n=9) and 13q32 (n=7), suggesting that these regions contain DNA sequences with a high propensity for neocentromere formation. Therefore, we have addressed the role of primary DNA sequence in neocentromere formation by asking whether multiple independent neocentromeres that were cytologically localized to chromosome 13q32 are in fact localized to the same underlying genomic DNA. Analysis of four independent 13q32 neocentromeres using simultaneous FISH with ordered YAC probes and immunofluorescence with antibodies to CENP-C have localized three neocentromeres to a distal approximately 7 Mb domain in chromosome 13q32, and one to an overlapping proximal domain of approximately 7 Mb. DNA was obtained from three of these neocentromeres by CENP-A chromatin immunoprecipitation (ChIP) and used to screen ordered BACs using both a slot-blotted BAC pool approach and a genomic microarray that contiguously spans 13q31.3-13q33.1. The CENP-A binding domains from each of these neocentromeres was identified to distinct genomic locations of approximately 130, 215 and 275 kb within an approximately 6.5 Mb region. Thus, the lack of coincidence of these neocentromeres to the same underlying DNA sequence refutes the idea of a DNA sequence based neocentromere 'hotspot' in 13q32 and further supports the sequence-independent epigenetic formation of human neocentromeres. The screening of genomic microarrays with ChIP DNA provides a powerful method to identify mammalian DNA sequences associated with particular functional chromatin states.
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MESH Headings
- Autoantigens/chemistry
- Cell Line
- Centromere/ultrastructure
- Centromere Protein A
- Chromatin/metabolism
- Chromosomal Proteins, Non-Histone/chemistry
- Chromosomes, Artificial, Bacterial
- Chromosomes, Artificial, Yeast
- Chromosomes, Human, Pair 13
- DNA/chemistry
- HeLa Cells
- Humans
- In Situ Hybridization, Fluorescence
- Microscopy, Fluorescence
- Models, Genetic
- Nucleic Acid Hybridization
- Oligonucleotide Array Sequence Analysis/methods
- Polymerase Chain Reaction
- Precipitin Tests
- Protein Structure, Tertiary
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Affiliation(s)
- Alicia Alonso
- Department of Human Genetics, Box 1498, Mount Sinai School of Medicine, 1425 Madison Ave, East Bldg 14-52A, New York, NY 10029, USA
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Abstract
The availability of almost the complete human genome as cloned BAC libraries represents a valuable resource for functional genomic analysis, which, however, has been somewhat limited by the ability to modify and transfer this DNA into mammalian cells intact. Here we report a novel comprehensive Escherichia coli-based vector system for the modification, propagation and delivery of large human genomic BAC clones into mammalian cells. The GET recombination inducible homologous recombination system was used in the BAC host strain E.coli DH10B to precisely insert an EGFPneo cassette into the vector portion of a approximately 200 kb human BAC clone, providing a relatively simple method to directly convert available BAC clones into suitable vectors for mammalian cells. GET recombination was also used for the targeted deletion of the asd gene from the E.coli chromosome, resulting in defective cell wall synthesis and diaminopimelic acid auxotrophy. Transfer of the Yersinia pseudotuberculosis invasin gene into E.coli DH10B asd(-) rendered it competent to invade HeLa cells and deliver DNA, as judged by transient expression of green fluorescent protein and stable neomycin-resistant colonies. The efficiency of DNA transfer and survival of HeLa cells has been optimized for incubation time and multiplicity of infection of invasive E.coli with HeLa cells. This combination of E.coli-based homologous recombination and invasion technologies using BAC host strain E.coli DH10B will greatly improve the utility of the available BAC libraries from the human and other genomes for gene expression and functional genomic studies.
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Affiliation(s)
- Kumaran Narayanan
- Department of Human Genetics, Box 1498, Mount Sinai School of Medicine, 1425 Madison Avenue, East Building 14-52A, New York, NY 10029, USA
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Knegt AC, Li S, Engelen JJM, Bijlsma EK, Warburton PE. Prenatal diagnosis of a karyotypically normal pregnancy in a mother with a supernumerary neocentric 13q21 -->13q22 chromosome and balancing reciprocal deletion. Prenat Diagn 2003; 23:215-20. [PMID: 12627422 DOI: 10.1002/pd.559] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An adult female patient with a history of miscarriages was found to be carrying a stable supernumerary chromosome. The patient also carried a reciprocal paracentric deletion in chromosome 13q21/22. Microdissection and reverse fluorescence in situ hybridization FISH revealed that this supernumerary chromosome was derived from region 13q21 --> 13q22. The presence of a neocentromere on this supernumerary chromosome was confirmed by the absence of detectable alpha satellite DNA using FISH and the presence of centromere proteins CENP-C and CENP-A using immunofluorescence. The absence of telomere sequences suggests that the marker is a ring chromosome (r(13)). FISH using ordered BACs from the chromosome region 13q21 --> 13q31 permitted the precise positioning of the r(13) chromosome and the corresponding deletion to chromosome bands 13q21.32 --> 13q22.2. BAC 280J7 from within the r(13) was used as a FISH probe for the prenatal analysis of amniocytes at 16 weeks of gestation, which revealed a normal karyotype for the fetus. This r(13) chromosome represents the first description of chromosome 13 of the rarer class of neocentric chromosomes that are derived from interstitial deletions. It represents the first example of prenatal diagnosis in a phenotypically normal female that was ascertained to carry a neocentric marker. The presence of such a neocentric marker/deletion karyotype in a parent presents unique possible karyotypic outcomes for conceptions and unusual challenges for genetic counseling.
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Affiliation(s)
- A C Knegt
- Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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Assumpção JG, Berkofsky-Fessler W, Viguetti Campos N, Trevas Maciel-Guerra A, Li S, Melaragno MI, Palandi de Mello M, Warburton PE. Identification of a neocentromere in a rearranged Y chromosome with no detectable DYZ3 centromeric sequence. Am J Med Genet 2002; 113:263-7. [PMID: 12439894 DOI: 10.1002/ajmg.10701] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An 18-year-old woman was evaluated because of primary amenorrhea and hypogonadism. Chromosome analysis from peripheral blood lymphocytes revealed a nonmosaic 46,X,+mar constitution. The marker was shown to be a rearranged Y chromosome consisting of an inverted duplication of the long arm: rea(Y)(qter-q11::q11-qter). Deletion mapping analysis with Y-specific STS showed that the marker lacked Yp and Y-centromeric (DYZ3) sequences, but it was positive for Yq sequences tested. Fluorescence in situ hybridization analysis with Y and X chromosome centromeric and pancentromeric probes showed no hybridization signals. The marker chromosome is present in 100% of the cells; therefore, it is mitotically stable despite the absence of DYZ3 centromeric sequence. Hybridization with CENP-A and CENP-C specific antibodies localized a neocentromere close to the breakpoint.
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Affiliation(s)
- Juliana Godoy Assumpção
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil
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24
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Abstract
Karyotypes from independent amniocenteses reflected a rare, unstable, functionally dicentric Robertsonian translocation chromosome in most cells in male Twin B who grew more slowly than the chromosomally normal female sib (Twin A). Twin B's balanced de novo Robertsonian translocation dic(13;14)(p11.1;p11.1), present in 81% of cells, underwent recurrent centromeric fission in 6 out of 30 independent colonies that explains a balanced 46,XY,-13,+fis(13)(p11.1),-14,+fis(14)(p11.1) karyotype. Aneuploidy for chromosomes 13q or 14q was present in 5% of cells. Instability of the Robertsonian translocation was evident because nine of the 30 colonies (30%) grown from single amniocytes had metaphase cells with more than one chromosome complement. Although uniparental disomy was excluded and a targeted ultrasound was normal, the couple was advised of the uncertain but real risk of abnormalities in Twin B and the risk to Twin A of terminating Twin B. The pregnancy proceeded and at 31 weeks gestation Twin A was in the 33rd percentile for size and Twin B in the 1st percentile. At 32 weeks, chromosome analysis revealed a balanced 45,XY,dic(13;14)(p11.1;p11.1) karyotype in all of Twin B's newborn cord blood cells with no evidence of fission or aneuploidy. Selection against unbalanced mitotic products of the unstable, functionally dicentric chromosome in early fetal development is proposed to result in Twin B's highly discordant small birth size.
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Affiliation(s)
- R V Lebo
- Center for Human Genetics and Department of Pediatrics, Boston University School of Medicine, Boston, MA, USA.
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25
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Li S, Malafiej P, Levy B, Mahmood R, Field M, Hughes T, Lockhart LH, Wu Z, Huang M, Hirschhorn K, Velagaleti GVN, Daniel A, Warburton PE. Chromosome 13q neocentromeres: molecular cytogenetic characterization of three additional cases and clinical spectrum. Am J Med Genet 2002; 110:258-67. [PMID: 12116235 DOI: 10.1002/ajmg.10454] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We report three new cases of chromosome 13 derived marker chromosomes, found in unrelated patients with dysmorphisms and/or developmental delay. Molecular cytogenetic analysis was performed using fluorescence in situ hybridization (FISH) with chromosome-specific painting probes, alpha satellite probes, and physically mapped probes from chromosome 13q, as well as comparative genomic hybridization (CGH). This analysis demonstrated that these markers consisted of inversion duplications of distal portions of chromosome 13q that have separated from the endogenous chromosome 13 centromere and contain no detectable alpha satellite DNA. The presence of a functional neocentromere on these marker chromosomes was confirmed by immunofluorescence with antibodies to centromere protein-C (CENP-C). The cytogenetic location of a neocentromere in band 13q32 was confirmed by simultaneous FISH with physically mapped YACs from 13q32 and immunofluorescence with anti-CENP-C. The addition of these three new cases brings the total number of described inv dup 13q neocentic chromosomes to 11, representing 21% (11/52) of the current overall total of 52 described cases of human neocentric chromosomes. This higher than expected frequency suggests that chromosome 13q may have an increased propensity for neocentromere formation. The clinical spectrum of all 11 cases is presented, representing a unique collection of polysomy for different portions of chromosome 13q without aneuploidies for additional chromosomal regions. The complexity and variability of the phenotypes seen in these patients does not support a simple reductionist view of phenotype/genotype correlation with polysomy for certain chromosomal regions.
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Affiliation(s)
- Shulan Li
- Department of Human Genetics Mount Sinai School of Medicine, New York, New York 10029, USA
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26
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Abstract
Recent advances in chromosome engineering and the potential for downstream applications in gene therapy were presented at the Artificial Chromosome Session of Genome Medicine: Gene Therapy for the Millennium in Rome, Italy in September 2001. This session concentrated primarily on the structure and function of human centromeres and the ongoing challenge of equipping human artificial chromosomes (HACs) with centromeres to ensure their mitotic stability. Advances in the 'bottom up' construction of HACs included the transfer into HT1080 cells of circular PACs containing alpha satellite DNA, and the correction of HPRT deficiency in cells using HACs. Advances in the 'top down' construction of HACs using telomere associated chromosome fragmentation in DT40 cells included the formation of HACs that are less than a megabase in size and transfer of HACs through the mouse germline. Significant progress has also been made in the use of human minichromosomes for stable trans-gene expression. While many obstacles remain towards the use of HACs for gene therapy, this session provided an optimistic outlook for future success.
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Affiliation(s)
- B R Grimes
- Department of Genetics, School of Medicine, Case Western Reserve University and University Hospital of Cleveland, Cleveland, OH 44106, USA
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27
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Yoon JT, Palazzo AF, Xiao D, Delohery TM, Warburton PE, Bruce JN, Thompson WJ, Sperl G, Whitehead C, Fetter J, Pamukcu R, Gundersen GG, Weinstein IB. CP248, a derivative of exisulind, causes growth inhibition, mitotic arrest, and abnormalities in microtubule polymerization in glioma cells. Mol Cancer Ther 2002; 1:393-404. [PMID: 12477052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
Exisulind (sulindac sulfone) and two potent derivatives, CP248 and CP461, have been shown previously to cause growth inhibition and apoptosis in several types of human carcinoma cell lines. These and related compounds have not been previously studied with respect to glioma cell lines. In the present study, we found that these three compounds caused marked growth inhibition in four rat glioma and eight human glioma cell lines, with IC50 values of 150, 1, and 0.075 microm, respectively. When studied at these concentrations exisulind and CP461 had no significant effect on the cell cycle profile of glioma cells, but CP248 caused marked arrest in mitosis. Detailed studies of CP248 in the 9L rat gliosarcoma cell line indicated that treatment with 0.075 microM CP248 caused abnormalities in the spindle apparatus and activation of the spindle assembly check point. In interphase glioma cells, CP248 stabilized microtubules (MTs) at low concentrations (0.075 microM) and depolymerized MTs at higher concentrations (0.2-0.4 microM). In NIH 3T3 fibroblasts, 0.1 microM CP248 caused extensive MT depolymerization. CP248 also caused MT depolymerization when added to assembled MTs in vitro, which indicated that it can directly affect MTs, perhaps because it shares certain structural similarities with Colcemid. In glioma cells, the effects of CP248 on MTs were independent of the previously reported effects of this compound on activation of protein kinase G. Therefore, CP248 is a novel MT-active agent that may be useful in the treatment of glioblastoma, and possibly other types of cancer, because of its dual effects on protein kinase G and MTs.
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Affiliation(s)
- Jung-Taek Yoon
- Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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28
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Levy B, Jalal SM, Dunn TM, Warburton PE, Tonk VS, Hirschhorn K, Lockhart LH, Hughes T, Velagaleti GVN. Unique case of mosaicism involving two morphologically similar marker chromosomes of different centric origin in a patient with developmental delay. Am J Med Genet 2002; 108:198-204. [PMID: 11891685 DOI: 10.1002/ajmg.10263] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A five-year-old Caucasian male presented with developmental delay, minor dysmorphic features, and hyperactivity. Cytogenetic analysis showed the presence of a marker chromosome in the majority of cells analyzed. Fluorescence in situ hybridization (FISH) analyses using several alpha satellite probes, including D13Z1/D21Z1, did not reveal any signal on the marker chromosome. Subsequent multicolor FISH (M-FISH) indicated the marker to be derived from chromosome 13, and FISH with a chromosome 13 paint confirmed this finding. The absence of D13Z1/D21Z1 signal on the marker suggested that it was analphoid in nature. Comparative genomic hybridization (CGH) was utilized to further characterize the region of chromosome 13 from which the marker originated, and unexpectedly revealed a gain of chromosomal material at both the centromeric regions of chromosomes 3 and 13. In view of the CGH results, extensive FISH studies with D3Z1 and D13Z1/D21Z1 were performed and revealed the presence of four cell lines comprising one normal cell line (50.5%), a cell line with a chromosome 3 derived marker (19%), a cell line containing a marker derived from chromosome 13 (20%), and a cell line with both markers (10.5%). As the two markers appeared morphologically similar by GTG banding, all 47,XY metaphases in the initial analysis were thought to comprise only a single marker. This is the first report, to our knowledge, of the presence of a chromosome 3 and a chromosome 13 marker in mosaic condition in a congenital disorder. In light of our experience, we urge caution in interpreting karyotypes with marker chromosomes. Our case illustrates the limitations of fluorescent DNA probes and sampling errors.
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Affiliation(s)
- Brynn Levy
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York, USA
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29
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Abstract
Human centromere formation involves the assembly of the mitotic kinetochore onto chromosomal locations that contain the interphase prekinetochore. Immunofluorescent analysis of two functionally converse human centromere variants, neocentromeres and inactive centromeres, has been used to evaluate the functional significance of over 24 CENTROMERE proteins, providing important insight into the epigenetics of centromere formation and kinetochore assembly.
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Affiliation(s)
- P E Warburton
- Dept of Human Genetics, PO Box 1498, Mount Sinai School of Medicine, East Building 14-52A, 1425 Madison Ave, New York, NY 10029, USA.
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30
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Abstract
We describe a novel rearranged human Y chromosome consisting of an inverted duplication of the long arm heterochromatin and a small amount of euchromatin: rea(Y)(qter-q11.2::q11.2-qter). The normal centromere has been deleted and a neocentromere containing CENP-A, -C, -E and Mad2 but not CENP-B has formed close to the breakpoint. A 2.7 Mb yeast artificial chromosome contig spanning the breakpoint was constructed and the breakpoint was localised to a region of <120 kb close to the DAZ gene cluster. Combined immunofluorescence and fluorescence in situ hybridisation showed that the centromeric protein-binding domain of the neocentromere was located near the breakpoint and within the DAZ cluster.
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Affiliation(s)
- G Floridia
- Department of Biochemistry, University of Oxford, UK
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31
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Sugata N, Li S, Earnshaw WC, Yen TJ, Yoda K, Masumoto H, Munekata E, Warburton PE, Todokoro K. Human CENP-H multimers colocalize with CENP-A and CENP-C at active centromere--kinetochore complexes. Hum Mol Genet 2000; 9:2919-26. [PMID: 11092768 DOI: 10.1093/hmg/9.19.2919] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Centromere and kinetochore proteins have a pivotal role in centromere structure, kinetochore formation and sister chromatid separation. However, the molecular architecture and the precise dynamic function of the centromere-kinetochore complex during mitosis remain poorly understood. Here we report the isolation and characterization of human CENP-H. Confocal microscopic analyses of HeLa cells with anti-human CENP-H-specific antibody demonstrated that CENP-H colocalizes with inner kinetochore plate proteins CENP-A and CENP-C in both interphase and metaphase. CENP-H was present outside centromeric heterochromatin, where CENP-B is localized, and inside the kinetochore corona, where CENP-E is localized during prometaphase. Furthermore, CENP-H was detected at neocentromeres, but not at inactive centromeres in stable dicentric chromosomes. In vitro binding assays of human CENP-H with centromere-kinetochore proteins suggest that the CENP-H binds to itself and MCAK, but not to CENP-A, CENP-B or CENP-C. CENP-H multimers were observed in cells in which both FLAG-tagged CENP-H and hemagglutinin-tagged CENP-H were expressed. These results suggest that CENP-H multimers localize constitutively to the inner kinetochore plate and play an important fundamental role in organization and function of the active human centromere-kinetochore complex.
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Affiliation(s)
- N Sugata
- Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN), 3-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
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32
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Warburton PE, Dolled M, Mahmood R, Alonso A, Li S, Naritomi K, Tohma T, Nagai T, Hasegawa T, Ohashi H, Govaerts LC, Eussen BH, Van Hemel JO, Lozzio C, Schwartz S, Dowhanick-Morrissette JJ, Spinner NB, Rivera H, Crolla JA, Yu C, Warburton D. Molecular cytogenetic analysis of eight inversion duplications of human chromosome 13q that each contain a neocentromere. Am J Hum Genet 2000; 66:1794-806. [PMID: 10777715 PMCID: PMC1378043 DOI: 10.1086/302924] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2000] [Accepted: 03/13/2000] [Indexed: 11/03/2022] Open
Abstract
Neocentromeres are fully functional centromeres that have arisen in previously noncentromeric chromosomal locations on rearranged chromosomes. The formation of neocentromeres results in the mitotic stability of chromosomal fragments that do not contain endogenous centromeres and that would normally be lost. Here we describe a unique collection of eight independent patient-derived cell lines, each of which contains a neocentromere on a supernumerary inversion duplication of a portion of human chromosome 13q. Findings in these patients reveal insight into the clinical manifestations associated with polysomy for portions of chromosome 13q. The results of FISH and immunofluorescent analysis of the neocentromeres in these chromosomes confirm the lack of alpha-satellite DNA and the presence of CENtromere proteins (CENP)-C, -E, and hMAD2. The positions of the inversion breakpoints in these chromosomes have been placed onto the physical map of chromosome 13, by means of FISH mapping with cosmid probes. These cell lines define, within chromosome 13q, at least three distinct locations where neocentromeres have formed, with five independent neocentromeres in band 13q32, two in band 13q21, and one in band 13q31. The results of examination of the set of 40 neocentromere-containing chromosomes that have thus far been described, including the 8 neocentromere-containing chromosomes from chromosome 13q that are described in the present study, suggest that chromosome 13q has an increased propensity for neocentromere formation, relative to some other human chromosomes. These neocentromeres will provide the means for testing hypotheses about sequence requirements for human centromere formation.
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Affiliation(s)
- P E Warburton
- Department of Human Genetics, Mount Sinai School of Medicine, New York, NY, 10029, USA.
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33
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Abstract
Mammalian artificial chromosomes (MACs) hold the promise of providing autonomous vectors for gene therapy in dividing cells. They would not require insertion into the genome and could include sufficient genomic sequences that surround the therapeutic gene to ensure proper tissue-specific and temporal regulation. Several groups have reported successful formation of MACs in human cells using transfection strategies that included alpha satellite DNA, the primary DNA found at normal human centromeres. These results, although extremely encouraging, have limitations such as unpredictable chromosome formation and success thus far in only one transformed human cell line. Examination of other cells where alpha satellite DNA has integrated into ectopic chromosomal locations, as well as naturally occurring dicentric and neocentromere-containing cell lines, suggests that alpha satellite DNA may not be necessary or sufficient for centromere formation. Overall, these results suggest that epigenetic modifications of centromeric DNA are required for efficient centromere formation. Models for this centromere-specific epigenetic modification include a specialized chromatin structure and differential replication timing of centromeric DNA. Thus, further investigation of these centromere-specific epigenetic modifications may suggest strategies for increasing the efficiency of generating human artificial chromosomes for use as gene therapy vectors.
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Affiliation(s)
- P E Warburton
- Department of Human Genetics, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, New York, 10029, USA
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34
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Tyler-Smith C, Gimelli G, Giglio S, Floridia G, Pandya A, Terzoli G, Warburton PE, Earnshaw WC, Zuffardi O. Transmission of a fully functional human neocentromere through three generations. Am J Hum Genet 1999; 64:1440-4. [PMID: 10205277 PMCID: PMC1377882 DOI: 10.1086/302380] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
An unusual Y chromosome with a primary constriction inside the long-arm heterochromatin was found in the amniocytes of a 38-year-old woman. The same Y chromosome was found in her husband and brother-in-law, thus proving that it was already present in the father. FISH with alphoid DNA showed hybridization signals at the usual position of the Y centromere but not at the primary constriction. Centromere proteins (CENP)-A, CENP-C, and CENP-E could not be detected at the site of the canonic centromere but were present at the new constriction, whereas CENP-B was not detected on this Y chromosome. Experiments with 82 Y-specific loci distributed throughout the chromosome confirmed that no gross deletion or rearrangement had taken place, and that the Y chromosome belonged to a haplogroup whose members have a mean alphoid array of 770 kb (range 430-1,600 kb), whereas that of this case was approximately 250 kb. Thus, this Y chromosome appeared to be deleted for part of the alphoid DNA. It seems likely that this deletion was responsible for the silencing of the normal centromere and that the activation of the neocentromere prevented the loss of this chromosome. Alternatively, neocentromere activation could have occurred first and stimulated inactivation of the normal centromere by partial deletion. Whatever the mechanism, the presence of this chromosome in three generations demonstrates that it functions sufficiently well in mitosis for male sex determination and fertility and that neocentromeres can be transmitted normally at meiosis.
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Affiliation(s)
- C Tyler-Smith
- CRC Chromosome Molecular Biology Group, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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35
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Warburton PE, Cooke CA, Bourassa S, Vafa O, Sullivan BA, Stetten G, Gimelli G, Warburton D, Tyler-Smith C, Sullivan KF, Poirier GG, Earnshaw WC. Immunolocalization of CENP-A suggests a distinct nucleosome structure at the inner kinetochore plate of active centromeres. Curr Biol 1997; 7:901-4. [PMID: 9382805 DOI: 10.1016/s0960-9822(06)00382-4] [Citation(s) in RCA: 261] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The trilaminar kinetochore directs the segregation of chromosomes in mitosis and meiosis. Despite its importance, the molecular architecture of this structure remains poorly understood [1]. The best known component of the kinetochore plates is CENP-C, a protein that is required for kinetochore assembly [2], but whose molecular role in kinetochore structure and function is unknown. Here we have raised for the first time monospecific antisera to CENP-A [3], a 17 kD centromere-specific histone variant that is 62% identical to the carboxy-terminal domain of histone H3 [4,5] and that resembles the yeast centromeric component CSE4 [6]. We have found by simultaneous immunofluorescence with centromere antigens of known ultrastructural location that CENP-A is concentrated in the region of the inner kinetochore plate at active centromeres. Because CENP-A was previously shown to co-purify with nucleosomes [7], our data suggest a specific nucleosomal substructure for the kinetochore. In human cells, these kinetochore-specific nucleosomes are enriched in alpha-satellite DNA [8]. However, the association of CENP-A with neocentromeres lacking detectable alpha-satellite DNA, and the lack of CENP-A association with alpha-satellite-rich inactive centromeres of dicentric chromosomes together suggest that CENP-A association with kinetochores is unlikely to be determined solely by DNA sequence recognition. We speculate that CENP-A binding could be a consequence of epigenetic tagging of mammalian centromeres.
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Affiliation(s)
- P E Warburton
- Institute of Cell and Molecular Biology, University of Edinburgh, UK
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36
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Warburton PE, Cooke HJ. Hamster chromosomes containing amplified human alpha-satellite DNA show delayed sister chromatid separation in the absence of de novo kinetochore formation. Chromosoma 1997; 106:149-59. [PMID: 9233988 DOI: 10.1007/s004120050234] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The centromeres of human chromosomes contain large amounts of the tandemly repeated alpha-satellite DNA family. Previous studies have shown that integration of alpha-satellite DNA into ectopic locations in mammalian chromosomes can result in the de novo formation of several features of centromeric function. Here we further examine the possible centromeric properties of alpha-satellite DNA by introducing it into hamster chromosomes. A large amplified region of ectopic alpha-satellite DNA was shown to direct binding of anticentromere antibodies (ACAs) and centromere protein B (CENP-B). The chromosome containing these ectopic arrays showed a high frequency of formation of anaphase bridges. Owing to the favourable morphology of these chromosomes, we were able to determine that this bridging was due to delayed sister chromatid disjunction at the location of the ectopic alpha-satellite, and not due to de novo formation of a fully functional kinetochore. A separate hamster cell line containing large tandemly repeated amplicons including the DHFR gene also displayed similar behaviour during anaphase. These results may support a role for alpha-satellite DNA in sister chromatid cohesion at centromeres. However, other repetitive DNA in favourable configurations appears to be capable of mimicking this behaviour during anaphase.
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Affiliation(s)
- P E Warburton
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, EH4 2XU, UK.
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37
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38
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Abstract
The highly conserved centromere-associated protein CENP-B is a common feature of mammalian centromeres. Binding sites for CENP-B, so-called 'CENP-B boxes', are present in the otherwise unrelated centromeric satellite DNAs of humans, Mus musculus, Mus caroli, ferrets, giant pandas, tree shrews and gerbils, suggesting a role for CENP-B in centromere function. However, CENP-B and its binding sites are not detected at the centromeres of mammalian Y chromosomes and few, if any, binding sites seem present on African green monkey chromosomes. There is extensive sequence similarity between CENP-B and transposase proteins encoded by the pogo superfamily of transposable elements, which includes the human Tigger elements. Intriguingly, Tigger 2 has an almost perfect match to the CENP-B-binding site within its terminal inverted repeat. Comparison of the amino acid sequence of CENP-B with related proteins raises the possibility that CENP-B might share the ability to cause single-stranded DNA breaks. Such nicks could promote recombination, as has been suggested for the Charcot-Marie-Tooth disease duplication where a recombination hotspot exists close to a mariner-like element. We suggest that by promoting nicks adjacent to CENP-B boxes, CENP-B might facilitate the evolution and maintenance of satellite sequence arrays, rather than have a direct role in centromere function.
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Affiliation(s)
- D Kipling
- MRC Human Genetics Unit, Western General Hospital, Edinburgh
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39
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Abstract
DNA topoisomerase II (topo II) is involved in chromosome structure and function, although its exact location and role in mitosis are somewhat controversial. This is due in part to the varied reports of its localization on mitotic chromosomes, which has been described at different times as uniformly distributed, axial on the chromosome arms and predominantly centromeric. These disparate results are probably due to several factors, including use of different preparation and fixation techniques, species differences and changes in distribution during the cell cycle. Recently, several papers have re-investigated the distribution of topo II on chromosomes as a function of cell cycle and species(1-3). The new studies suggest that Topo II has a dynamic pattern of distribution on the chromosomes, in general becoming axial as chromosomes condense during prophase and then concentrating at centromeres during metaphase. These experiments suggest a novel role for topo II in centromere structure and function.
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Affiliation(s)
- P E Warburton
- Institute of Cell and Molecular Biology, University of Edinburgh, UK
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40
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O'Keefe CL, Warburton PE, Matera AG. Oligonucleotide probes for alpha satellite DNA variants can distinguish homologous chromosomes by FISH. Hum Mol Genet 1996; 5:1793-9. [PMID: 8923008 DOI: 10.1093/hmg/5.11.1793] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Chromosomal heteromorphisms have been used extensively to mark individual chromosomes. However, classical banding techniques used to identify these structural variants are imprecise and difficult to quantify. Different chromosomes 17 from the human population are characterized by distinct haplotypes of alpha satellite DNA. We have used these sequence variants to construct oligonuoleotide probes for fluorescence in situ hybridization (FISH). These oligomers are the first reported FISH probes that can discriminate between cytogenetically indistinguishable chromosome homologues. They have been used to follow the transmission of a single chromosome 17 through a pedigree, similar to a typical polymorphic marker. Furthermore, extended chromatin fiber techniques reveal the presence of discrete domains of different sequence variants within individual centromeres. Extension of this strategy to create a battery of other variant-specific oligoprobes should provide a powerful diagnostic tool for parent of origin effects in the study of aneuploidy, imprinting and cancer cytogenetics.
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Affiliation(s)
- C L O'Keefe
- Department of Genetics, Case Western Reserve University and University Hospitals of Cleveland, OH 44106-4955, USA
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41
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Goldberg IG, Sawhney H, Pluta AF, Warburton PE, Earnshaw WC. Surprising deficiency of CENP-B binding sites in African green monkey alpha-satellite DNA: implications for CENP-B function at centromeres. Mol Cell Biol 1996; 16:5156-68. [PMID: 8756673 PMCID: PMC231516 DOI: 10.1128/mcb.16.9.5156] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Centromeres of mammalian chromosomes are rich in repetitive DNAs that are packaged into specialized nucleoprotein structures called heterochromatin. In humans, the major centromeric repetitive DNA, alpha-satellite DNA, has been extensively sequenced and shown to contain binding sites for CENP-B, an 80-kDa centromeric autoantigen. The present report reveals that African green monkey (AGM) cells, which contain extensive alpha-satellite arrays at centromeres, appear to lack the well-characterized CENP-B binding site (the CENP-B box). We show that AGM cells express a functional CENP-B homolog that binds to the CENP-B box and is recognized by several independent anti-CENP-B antibodies. However, three independent assays fail to reveal CENP-B binding sites in AGM DNA. Methods used include a gel mobility shift competition assay using purified AGM alpha-satellite, a novel kinetic electrophoretic mobility shift assay competition protocol using bulk genomic DNA, and bulk sequencing of 76 AGM alpha-satellite monomers. Immunofluorescence studies reveal the presence of significant levels of CENP-B antigen dispersed diffusely throughout the nuclei of interphase cells. These experiments reveal a paradox. CENP-B is highly conserved among mammals, yet its DNA binding site is conserved in human and mouse genomes but not in the AGM genome. One interpretation of these findings is that the role of CENP-B may be in the maintenance and/or organization of centromeric satellite DNA arrays rather than a more direct involvement in centromere structure.
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Affiliation(s)
- I G Goldberg
- Department of Cell Biology and Anatomy, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
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Warburton PE, Haaf T, Gosden J, Lawson D, Willard HF. Characterization of a chromosome-specific chimpanzee alpha satellite subset: evolutionary relationship to subsets on human chromosomes. Genomics 1996; 33:220-8. [PMID: 8660971 DOI: 10.1006/geno.1996.0187] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Alpha satellite DNA is a tandemly repeated DNA family found at the centromeres of all primate chromosomes examined. The fundamental repeat units of alpha satellite DNA are diverged 169- and 172-bp monomers, often found to be organized in chromosome-specific higher-order repeat units. The chromosomes of human (Homo sapiens (HSA)), chimpanzee (Pan troglodytes (PTR) and Pan paniscus), and gorilla (Gorilla gorilla) share a remarkable similarity and synteny. It is of interest to ask if alpha satellite arrays at centromeres of homologous chromosomes between these species are closely related (evolving in an orthologous manner) or if the evolutionary processes that homogenize and spread these arrays within and between chromosomes result in nonorthologous evolution of arrays. By using PCR primers specific for human chromosome 17-specific alpha satellite DNA, we have amplified, cloned, and characterized a chromosome-specific subset from the PTR chimpanzee genome. Hybridization both on Southern blots and in situ as well as sequence analysis show that this subset is most closely related, as expected, to sequences on HSA 17. However, in situ hybridization reveals that this subset is not found on the homologous chromosome in chimpanzee (PTR 19), but instead on PTR 12, which is homologous to HSA 2p.
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Affiliation(s)
- P E Warburton
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, United Kingdom
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Warburton PE, Willard HF. Interhomologue sequence variation of alpha satellite DNA from human chromosome 17: evidence for concerted evolution along haplotypic lineages. J Mol Evol 1995; 41:1006-15. [PMID: 8587099 DOI: 10.1007/bf00173182] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Alpha satellite DNA is a family of tandemly repeated DNA found at the centromeres of all primate chromosomes. Different human chromosomes 17 in the population are characterized by distinct alpha satellite haplotypes, distinguished by the presence of variant repeat forms that have precise monomeric deletions. Pair-wise comparisons of sequence diversity between variant repeat units from each haplotype show that they are closely related in sequence. Direct sequencing of PCR-amplified alpha satellite reveals heterogeneous positions between the repeat units on a chromosome as two bands at the same position on a sequencing ladder. No variation was detected in the sequence and location of these heterogeneous positions between chromosomes 17 from the same haplotype, but distinct patterns of variation were detected between chromosomes from different haplotypes. Subsequent sequence analysis of individual repeats from each haplotype confirmed the presence of extensive haplotype-specific sequence variation. Phylogenetic inference yielded a tree that suggests these chromosome 17 repeat units evolve principally along haplotypic lineages. These studies allow insight into the relative rates and/or timing of genetic turnover processes that lead to the homogenization of tandem DNA families.
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Affiliation(s)
- P E Warburton
- Department of Genetics, Stanford University, CA 94305, USA
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Abstract
The structure of the alpha satellite DNA higher-order repeat (HOR) unit from a subset shared by human chromosomes 13 and 21 (D13Z1 and D21Z1) has been examined in detail. By using a panel of hybrids possessing either a chromosome 13 or a chromosome 21, different HOR unit genotypes on chromosomes 13 and 21 have been distinguished. We have also determined the basis for a variant HOR unit structure found on approximately 8% of chromosomes 13 but not at all on chromosomes 21. Genomic restriction maps of the HOR units found on the two chromosome 13 genotypes and on the chromosome 21 genotype are constructed and compared. The nucleotide sequence of a predominant 1.9-kilobasepair HOR unit from the D13Z1/D21Z1 subset has been determined. The DNA sequences of different alpha satellite monomers comprising the HOR are compared, and the data are used to develop a model, based on unequal crossing-over, for the evolution of the current HOR unit found at the centromeres of both these chromosomes.
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MESH Headings
- Animals
- Base Sequence
- Biological Evolution
- Chromosomes, Human, Pair 13
- Chromosomes, Human, Pair 21
- Cloning, Molecular
- DNA, Satellite/genetics
- Deoxyribonucleases, Type II Site-Specific
- Genotype
- Humans
- Hybrid Cells
- Mice
- Models, Genetic
- Molecular Sequence Data
- Polymorphism, Genetic
- Repetitive Sequences, Nucleic Acid
- Restriction Mapping
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- G M Greig
- Department of Genetics, Stanford University, California 94305
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Warburton PE, Waye JS, Willard HF. Nonrandom localization of recombination events in human alpha satellite repeat unit variants: implications for higher-order structural characteristics within centromeric heterochromatin. Mol Cell Biol 1993; 13:6520-9. [PMID: 8413251 PMCID: PMC364711 DOI: 10.1128/mcb.13.10.6520-6529.1993] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Tandemly repeated DNA families appear to undergo concerted evolution, such that repeat units within a species have a higher degree of sequence similarity than repeat units from even closely related species. While intraspecies homogenization of repeat units can be explained satisfactorily by repeated rounds of genetic exchange processes such as unequal crossing over and/or gene conversion, the parameters controlling these processes remain largely unknown. Alpha satellite DNA is a noncoding tandemly repeated DNA family found at the centromeres of all human and primate chromosomes. We have used sequence analysis to investigate the molecular basis of 13 variant alpha satellite repeat units, allowing comparison of multiple independent recombination events in closely related DNA sequences. The distribution of these events within the 171-bp monomer is nonrandom and clusters in a distinct 20- to 25-bp region, suggesting possible effects of primary sequence and/or chromatin structure. The position of these recombination events may be associated with the location within the higher-order repeat unit of the binding site for the centromere-specific protein CENP-B. These studies have implications for the molecular nature of genetic recombination, mechanisms of concerted evolution, and higher-order structure of centromeric heterochromatin.
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Affiliation(s)
- P E Warburton
- Department of Genetics, Stanford University, California 94305
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Warburton PE, Willard HF. PCR amplification of tandemly repeated DNA: analysis of intra- and interchromosomal sequence variation and homologous unequal crossing-over in human alpha satellite DNA. Nucleic Acids Res 1992; 20:6033-42. [PMID: 1461735 PMCID: PMC334470 DOI: 10.1093/nar/20.22.6033] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Tandemly repeated DNA can comprise several percent of total genomic DNA in complex organisms and, in some instances, may play a role in chromosome structure or function. Alpha satellite DNA is the major family of tandemly repeated DNA found at the centromeres of all human and primate chromosomes. Each centromere is characterized by a large contiguous array of up to several thousand kb which can contain several thousand highly homogeneous repeat units. By using a novel application of the polymerase chain reaction (repPCR), we are able to amplify a representative sampling of multiple repetitive units simultaneously, allowing rapid analysis of chromosomal subsets. Direct sequence analysis of repPCR amplified alpha satellite from chromosomes 17 and X reveals positions of sequence heterogeneity as two bands at a single nucleotide position on a sequencing ladder. The use of TdT in the sequencing reactions greatly reduces the background associated with polymerase pauses and stops, allowing visualization of heterogeneous bases found in as little as 10% of the repeat units. Confirmation of these heterogeneous positions was obtained by comparison to the sequence of multiple individual cloned copies obtained both by PCR and non-PCR based methods. PCR amplification of alpha satellite can also reveal multiple repeat units which differ in size. Analysis of repPCR products from chromosome 17 and X allows rapid determination of the molecular basis of these repeat unit length variants, which appear to be a result of unequal crossing-over. The application of repPCR to the study of tandemly repeated DNA should allow in-depth analysis of intra- and interchromosomal variation and unequal crossing-over, thus providing insight into the biology and genetics of these large families of DNA.
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Affiliation(s)
- P E Warburton
- Department of Genetics, Stanford University, CA 94305
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Haaf T, Warburton PE, Willard HF. Integration of human alpha-satellite DNA into simian chromosomes: centromere protein binding and disruption of normal chromosome segregation. Cell 1992; 70:681-96. [PMID: 1505032 DOI: 10.1016/0092-8674(92)90436-g] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Centromeres of mammalian and other complex eukaryotic chromosomes are dominated by one or more classes of satellite DNA. To test the hypothesis that alpha-satellite DNA, the major centromeric satellite of primate chromosomes, is involved in centromere structure and/or function, human alpha-satellite DNA was introduced into African green monkey (AGM) cells. Centromere protein binding was apparent at the sites of integrated human alpha-satellite DNA. In the presence of an AGM centromere on the same chromosome, human alpha-satellite was associated with bridges between the separating sets of chromatids at anaphase and an increased number of lagging chromosomes at metaphase, both features consistent with the integrated alpha-satellite disrupting normal chromosome segregation. These experiments suggest that alpha-satellite DNA provides the primary sequence information for centromere protein binding and for at least some functional aspect(s) of a mammalian centromere, playing a role either in kinetochore formation or in sister chromatid apposition.
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Affiliation(s)
- T Haaf
- Department of Genetics, Stanford University School of Medicine, California 94305
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Warburton PE, Greig GM, Haaf T, Willard HF. PCR amplification of chromosome-specific alpha satellite DNA: definition of centromeric STS markers and polymorphic analysis. Genomics 1991; 11:324-33. [PMID: 1685138 DOI: 10.1016/0888-7543(91)90139-6] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Alpha satellite DNA is a tandemly repetitive DNA family found at the centromere of every human chromosome. Chromosome-specific subsets have been isolated for over half the chromosomes and have prove useful as markers for both genetic and physical mapping. We have developed specific oligonucleotide primer sets for polymerase chain reaction (PCR) amplification of alpha satellite DNA from chromosomes 3, 7, 13/21, 17, X, and Y. For each set of primers, PCR products amplified from human genomic DNA are specific for the centromere of the target chromosome(s), as shown by somatic cell hybrid mapping and by fluorescence in situ hybridization. These six subsets represent several evolutionarily related alpha satellite subfamilies, suggesting that specific primer pairs can be designed for most or all chromosomal subsets in the genome. The PCR products from chromosome 17 directly reveal the polymorphic nature of this subset, and a new DraI polymorphism is described. The PCR products from chromosome 13 are also polymorphic, allowing in informative cases genetic analysis of this centromeric subset distinguished from the highly homologous chromosome 21 subset. These primer sets should allow placement of individual centromeres on the proposed STS map of the human genome and may be useful for somatic cell hybrid characterization and for making in situ probes. In addition, the ability to amplify chromosome-specific repetitive DNA families directly will contribute to the structural and functional analysis of these abundant classes of DNA.
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Affiliation(s)
- P E Warburton
- Department of Genetics, Stanford University, California 94305
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Warburton PE, Willard HF. Genomic analysis of sequence variation in tandemly repeated DNA. Evidence for localized homogeneous sequence domains within arrays of alpha-satellite DNA. J Mol Biol 1990; 216:3-16. [PMID: 2122000 DOI: 10.1016/s0022-2836(05)80056-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
As a model to examine the local distribution of sequence variation within large arrays of tandemly repeated DNA in complex genomes, the long-range organization of alpha-satellite DNA from human chromosome 17 was investigated. Three individual chromosomes, representing different alpha-satellite haplotypes, were segregated into mouse and human somatic cell hybrids and their arrays sized by pulse-field gel electrophoresis. An inventory of the higher-order repeat units found in multiple separate regions of these megabase arrays was obtained using cosmid mapping and two-dimensional gel electrophoresis, a technique that combines the large-scale resolution of pulsed-field gel electrophoresis with the small-scale resolution of conventional gel electrophoresis. These analyses show that alpha-satellite arrays are characterized by the presence of localized homogeneous domains containing only one distinct type of repeat unit. These domains, which consist of sequence variants and/or higher-order repeat length variants, can be up to at least several hundred thousands of bases in length. Both abundant and rare variant repeat units can be localized in these distinct domains, which may correspond to transition states in the evolution of tandem multicopy DNA families. This description of the organization of large arrays of tandem repeats provides insight into mechanisms involved in their homogenization.
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Affiliation(s)
- P E Warburton
- Department of Medical Genetics, University of Toronto, Ontario, Canada
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