ATP-dependent looping of DNA by ISWI

Giuseppe Lia, Marco Indrieri, Tom Owen-Hughes, Laura Finzi, Alessandro Podesta, Paolo Milani, David Dunlap

    Research output: Contribution to journalArticlepeer-review

    11 Citations (Scopus)


    Snf2 related chromatin remodelling, enzymes possess an ATPase subunit similar to that of the SF-H helicases which hydrolyzes ATP to track along DNA, Translocation and any resulting torque in the DNA could drive chromatin remodeling. To determine whether the ISWI protein can translocate and generate torque, tethered particle motion experiments and atomic force microscopy have been performed using recombinant ISWI expressed in E. coli. In the absence of ATP, ISWT bound to and wrapped DNA thereby shortening the overall contour length measured in atomic force micrographs. Although naked DNA only weakly stimulates ATP hydrolysis by ISWI, both atomic force microscopy and tethered particle motion data indicate that the protein generated loops in the presence of ATP. The duration of the looped state of the DNA measured using tethered particle motion was ATP-dependent. Finally, ISWI relaxed positively supercoiled plasmids visualized by atomic force microscopy. While other chromatin remodeling ATPases catalyze either DNA wrapping or looping, both are catalyzed by ISWI. (C) 2008 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

    Original languageEnglish
    Pages (from-to)280-286
    Number of pages7
    JournalJournal of Biophotonics
    Issue number4
    Publication statusPublished - Sept 2008


    • tethered particle motion
    • ISWI
    • chromatin remodeling
    • atomic force microscopy
    • DNA looping
    • DNA supercoiling
    • RSC
    • SWI/SNF
    • ROLES


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