Frozen-hydrated chromatin from metaphase chromosomes has an interdigitated multilayer structure
| Autor: | Roberto Melero, Andrea Chicano, Eva Crosas, Joan-Ramon Daban, Benjamin D. Engel, Joaquín Otón |
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| Přispěvatelé: | Ministerio de Economía y Competitividad (España), European Commission |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Metaphase chromosome structure
Chromatin higher-order structure Biology Molecular physics Chromosomes General Biochemistry Genetics and Molecular Biology 03 medical and health sciences 0302 clinical medicine Monolayer Nucleosome Molecular Biology Metaphase 030304 developmental biology Cryo-electron tomography 0303 health sciences General Immunology and Microbiology Small-angle X-ray scattering Scattering DNA packaging General Neuroscience Chromosome Articles Chromatin Nucleosomes 030217 neurology & neurosurgery |
| Zdroj: | EMBO Journal Digital.CSIC. Repositorio Institucional del CSIC instname Digital.CSIC: Repositorio Institucional del CSIC Consejo Superior de Investigaciones Científicas (CSIC) |
| Popis: | Cryo‐electron tomography and small‐angle X‐ray scattering were used to investigate the chromatin folding in metaphase chromosomes. The tomographic 3D reconstructions show that frozen‐hydrated chromatin emanated from chromosomes is planar and forms multilayered plates. The layer thickness was measured accounting for the contrast transfer function fringes at the plate edges, yielding a width of ~ 7.5 nm, which is compatible with the dimensions of a monolayer of nucleosomes slightly tilted with respect to the layer surface. Individual nucleosomes are visible decorating distorted plates, but typical plates are very dense and nucleosomes are not identifiable as individual units, indicating that they are tightly packed. Two layers in contact are ~ 13 nm thick, which is thinner than the sum of two independent layers, suggesting that nucleosomes in the layers interdigitate. X‐ray scattering of whole chromosomes shows a main scattering peak at ~ 6 nm, which can be correlated with the distance between layers and between interdigitating nucleosomes interacting through their faces. These observations support a model where compact chromosomes are composed of many chromatin layers stacked along the chromosome axis. This work was supported in part by MINECO research grant BFU2010-18939, European Union (EU) and Horizon 2020 through grant West-Life (EINFRA-2015-1, Proposal: 675858), and a by a UAB-PIF predoctoral fellowship to AC. Cryo-ET experiments at Max-Planck-Institute of Biochemistry (Martinsried) and image processing at National Center of Biotechnology (Madrid) were funded by Instruct (PID250, PID2115), part of the European Strategy Forum on Research Infrastructures (ESFRI) and supported by national member subscriptions. |
| Databáze: | OpenAIRE |
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