DNA accessibility of chromatosomes quantified by automated image analysis of AFM data

• Verfasst von: Würtz, Martin [VerfasserIn]
• Verfasst von: Aumiller, Dennis [VerfasserIn]
• Verfasst von: Gundelwein, Lina [VerfasserIn]
• Verfasst von: Jung, Philipp [VerfasserIn]
• Verfasst von: Schütz, Christian [VerfasserIn]
• Verfasst von: Lehmann, Kathrin [VerfasserIn]
• Verfasst von: Tóth, Katalin [VerfasserIn]
• Verfasst von: Rohr, Karl [VerfasserIn]
• Titel: DNA accessibility of chromatosomes quantified by automated image analysis of AFM data
• Verf.angabe: Martin Würtz, Dennis Aumiller, Lina Gundelwein, Philipp Jung, Christian Schütz, Kathrin Lehmann, Katalin Tóth & Karl Rohr
• E-Jahr: 2019
• Jahr: 04 September 2019
• Umfang: 12 S.
• Fussnoten: Gesehen am 03.12.2019
• Titel Quelle: Enthalten in: Scientific reports
• Ort Quelle: [London] : Macmillan Publishers Limited, part of Springer Nature, 2011
• Jahr Quelle: 2019
• Band/Heft Quelle: 9(2019) Artikel-Nummer 12788, 12 Seiten
• ISSN Quelle: 2045-2322
• DOI: doi:10.1038/s41598-019-49163-4
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1684113539
• K10plus-PPN:
  Universitätsbibliothek
• Lokale URL UB: Zum Volltext

Abstract

DNA compaction and accessibility in eukaryotes are governed by nucleosomes and orchestrated through interactions between DNA and DNA-binding proteins. Using QuantAFM, a method for automated image analysis of atomic force microscopy (AFM) data, we performed a detailed statistical analysis of structural properties of mono-nucleosomes. QuantAFM allows fast analysis of AFM images, including image preprocessing, object segmentation, and quantification of different structural parameters to assess DNA accessibility of nucleosomes. A comparison of nucleosomes reconstituted with and without linker histone H1 quantified H1’s already described ability of compacting the nucleosome. We further employed nucleosomes bearing two charge-modifying mutations at position R81 and R88 in histone H2A (H2A R81E/R88E) to characterize DNA accessibility under destabilizing conditions. Upon H2A mutation, even in presence of H1, the DNA opening angle at the entry/exit site was increased and the DNA wrapping length around the histone core was reduced. Interestingly, a distinct opening of the less bendable DNA side was observed upon H2A mutation, indicating an enhancement of the intrinsic asymmetry of the Widom-601 nucleosomes. This study validates AFM as a technique to investigate structural parameters of nucleosomes and highlights how the DNA sequence, together with nucleosome modifications, can influence the DNA accessibility.