Please use this identifier to cite or link to this item:
Scopus Web of Science® Altmetric
Type: Journal article
Title: Single molecule analysis of DNA wrapping and looping by a circular 14mer wheel of the bacteriophage 186 CI repressor
Author: Wang, H.
Dodd, I.
Dunlap, D.
Shearwin, K.
Finzi, L.
Citation: Nucleic Acids Research, 2013; 41(11):5746-5756
Publisher: Oxford Univ Press
Issue Date: 2013
ISSN: 0305-1048
Statement of
Haowei Wang, Ian B. Dodd, David D. Dunlap, Keith E. Shearwin, and Laura Finzi
Abstract: The lytic–lysogenic decision in bacteriophage 186 is governed by the 186 CI repressor protein in a unique way. The 186 CI is proposed to form a wheel-like oligomer that can mediate either wrapped or looped nucleoprotein complexes to provide the cooperative and competitive interactions needed for regulation. Although consistent with structural, biochemical and gene expression data, many aspects of this model are based on inference. Here, we use atomic force microscopy (AFM) to reveal the various predicted wrapped and looped species, and new ones, for CI regulation of lytic and lysogenic transcription. Automated AFM analysis showed CI particles of the predicted dimensions on the DNA, with CI multimerization favoured by DNA binding. Measurement of the length of the wrapped DNA segments indicated that CI may move on the DNA, wrapping or releasing DNA on either side of the wheel. Tethered particle motion experiments were consistent with wrapping and looping of DNA by CI in solution, where in contrast to λ repressor, the looped species were exceptionally stable. The CI regulatory system provides an intriguing comparison with that of nucleosomes, which share the ability to wrap and release similar sized segments of DNA.
Keywords: Myoviridae; Repressor Proteins; DNA; Microscopy, Atomic Force; Models, Molecular; Viral Regulatory and Accessory Proteins
Rights: © The Author(s) 2013. Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact
RMID: 0020130268
DOI: 10.1093/nar/gkt298
Grant ID:
Appears in Collections:Molecular and Biomedical Science publications

Files in This Item:
File Description SizeFormat 
hdl_79811.pdfPublished version5.56 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.