title: Centromere location inArabidopsisis unaltered by extreme divergence in CENH3 protein sequence.
abstract: During cell division, spindle fibers attach to chromosomes at centromeres. The DNA sequence at regional centromeres is fast evolving with no conserved genetic signature for centromere identity. Instead CENH3, a centromere-specific histone H3 variant, is the epigenetic signature that specifies centromere location across both plant and animal kingdoms. Paradoxically, CENH3 is also adaptively evolving. An ongoing question is whether CENH3 evolution is driven by a functional relationship with the underlying DNA sequence. Here, we demonstrate that despite extensive protein sequence divergence, CENH3 histones from distant species assemble centromeres on the same underlying DNA sequence. We first characterized the organization and diversity of centromere repeats in wild-typeArabidopsis thalianaWe show thatA. thalianaCENH3-containing nucleosomes exhibit a strong preference for a unique subset of centromeric repeats. These sequences are largely missing from the genome assemblies and represent the youngest and most homogeneous class of repeats. Next, we tested the evolutionary specificity of this interaction in a background in which the nativeA. thalianaCENH3 is replaced with CENH3s from distant species. Strikingly, we find that CENH3 fromLepidium oleraceumandZea mays, although specifying epigenetically weaker centromeres that result in genome elimination upon outcrossing, show a binding pattern onA. thalianacentromere repeats that is indistinguishable from the native CENH3. Our results demonstrate positional stability of a highly diverged CENH3 on independently evolved repeats, suggesting that the sequence specificity of centromeres is determined by a mechanism independent of CENH3.
authors.affiliation: Plant Biology Department and Genome Center, University of California, Davis, California 95616, USA.
authors.forename: Shamoni
authors.identifier: 0000-0002-2880-7805
authors.initials: S
authors.lastname: Maheshwari
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466 Stadt Seeland, Germany.
authors.forename: Takayoshi
authors.identifier: 0000-0001-6370-3289
authors.initials: T
authors.lastname: Ishii
authors.affiliation: Department of Population Health and Reproduction, University of California, Davis, California 95616, USA.
authors.forename: C Titus
authors.identifier: 0000-0001-6001-2677
authors.initials: CT
authors.lastname: Brown
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466 Stadt Seeland, Germany.
authors.forename: Andreas
authors.identifier: 0000-0003-3419-239X
authors.initials: A
authors.lastname: Houben
authors.affiliation: Plant Biology Department and Genome Center, University of California, Davis, California 95616, USA.
authors.forename: Luca
authors.identifier: 0000-0003-2642-6619
authors.initials: L
authors.lastname: Comai
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002503:Centromere / Q000235:genetics*; D000076247:Centromere Protein A / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D009707:Nucleosomes / Q000378:metabolism; D011110:Polymorphism, Genetic
chemical_list: D029681:Arabidopsis Proteins; D000076247:Centromere Protein A; D009707:Nucleosomes