title: Centromere sliding on a mammalian chromosome.
abstract: The centromere directs the segregation of chromosomes during mitosis and meiosis. It is a distinct genetic locus whose identity is established through epigenetic mechanisms that depend on the deposition of centromere-specific centromere protein A (CENP-A) nucleosomes. This important chromatin domain has so far escaped comprehensive molecular analysis due to its typical association with highly repetitive satellite DNA. In previous work, we discovered that the centromere of horse chromosome 11 is completely devoid of satellite DNA; this peculiar feature makes it a unique model to dissect the molecular architecture of mammalian centromeres. Here, we exploited this native satellite-free centromere to determine the precise localization of its functional domains in five individuals: We hybridized DNA purified from chromatin immunoprecipitated with an anti CENP-A antibody to a high resolution array (ChIP-on-chip) of the region containing the primary constriction of horse chromosome 11. Strikingly, each individual exhibited a different arrangement of CENP-A binding domains. We then analysed the organization of each domain using a single nucleotide polymorphism (SNP)-based approach and single molecule analysis on chromatin fibres. Examination of the ten instances of chromosome 11 in the five individuals revealed seven distinct 'positional alleles', each one extending for about 80-160 kb, were found across a region of about 500 kb. Our results demonstrate that CENP-A binding domains are autonomous relative to the underlying DNA sequence and are characterized by positional instability causing the sliding of centromere position. We propose that this dynamic behaviour may be common in mammalian centromeres and may determine the establishment of epigenetic alleles.
authors.affiliation: Dipartimento di Farmacia e Biotecnologie (FABIT), Università di Bologna, Bologna, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Purgato
authors.forename: Elisa
authors.initials: E
authors.lastname: Belloni
authors.forename: Francesca M
authors.initials: FM
authors.lastname: Piras
authors.forename: Monica
authors.initials: M
authors.lastname: Zoli
authors.forename: Claudia
authors.initials: C
authors.lastname: Badiale
authors.forename: Federico
authors.initials: F
authors.lastname: Cerutti
authors.forename: Alice
authors.initials: A
authors.lastname: Mazzagatti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Perini
authors.forename: Giuliano
authors.initials: G
authors.lastname: Della Valle
authors.forename: Solomon G
authors.initials: SG
authors.lastname: Nergadze
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Sullivan
authors.forename: Elena
authors.initials: E
authors.lastname: Raimondi
authors.forename: Mariano
authors.initials: M
authors.lastname: Rocchi
authors.forename: Elena
authors.initials: E
authors.lastname: Giulotto
mesh_terms: D000483:Alleles; D000818:Animals; D001324:Autoantigens / Q000235:genetics; D002460:Cell Line; D002503:Centromere / Q000235:genetics*; D000076247:Centromere Protein A; D002843:Chromatin / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D033481:Chromosomes, Mammalian / Q000235:genetics*; D003001:Cloning, Molecular; D004276:DNA, Satellite; D044127:Epigenesis, Genetic; D005260:Female; D006736:Horses / Q000235:genetics*; D008297:Male; D008540:Meiosis; D046208:Microchip Analytical Procedures; D008938:Mitosis; D009707:Nucleosomes / Q000235:genetics; D020641:Polymorphism, Single Nucleotide
chemical_list: D001324:Autoantigens; D000076247:Centromere Protein A; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004276:DNA, Satellite; D009707:Nucleosomes