Open and closed domains in the mouse genome are configured as 10‐nm chromatin fibres |
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| Authors: | Ugljesa Djuric Ren Li Kashif Ahmed Michael Hart James Ellis David P Bazett‐Jones |
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| Institution: | 1. Program in Developmental and Stem Cell Biology, Hospital for Sick Children, , Toronto, Ontario, Canada, M5G 1L7;2. Department of Molecular Genetics, University of Toronto, , Toronto, Ontario, Canada, M5S 1A8;3. Program in Genetics and Genome Biology, Hospital for Sick Children, TMDT, MaRS Centre 101 College St Room 15‐307, , Toronto, Ontario, Canada, MSG 1L7;4. Department of Biological Sciences, Simon Fraser University, , Burnaby, British Columbia, Canada, V5A 1S6;5. Department of Biochemistry, University of Toronto, , Toronto, Ontario, Canada, M5S 1A8 |
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| Abstract: | The mammalian genome is compacted to fit within the confines of the cell nucleus. DNA is wrapped around nucleosomes, forming the classic ‘beads‐on‐a‐string’ 10‐nm chromatin fibre. Ten‐nanometre chromatin fibres are thought to condense into 30‐nm fibres. This structural reorganization is widely assumed to correspond to transitions between active and repressed chromatin, thereby representing a chief regulatory event. Here, by combining electron spectroscopic imaging with tomography, three‐dimensional images are generated, revealing that both open and closed chromatin domains in mouse somatic cells comprise 10‐nm fibres. These findings indicate that the 30‐nm chromatin model does not reflect the true regulatory structure in vivo. |
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| Keywords: | chromatin fibre nuclear organization electron tomography |
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