Single Hepatitis-B virus core capsid binding to individual nuclear pore complexes in HeLa cells
YORIKO LILL 1, MARKUS A. LILL 2, BIRTHE FAHRENKROG 3, KYRILL SCHWARZ-HERION 3, SARA PAULILLO 3, Ueli Aebi 3 and Bert Hecht 1*
1 Institute of Physics, University of Basel
2 Biographics Laboratory 3R and Department of Molecular Pharmacy, University of Basel
3 M.E. Müller Institute, Biozentrum, University of Basel
* To whom correspondence should be addressed. E-mail: bert.hecht{at}nano-optics.ch.
Submitted on April 24, 2006
Revised on June 29, 2006
Accepted on 12 July 2006
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Abstract |
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We investigate the interaction of Hepatitis B virus capsids lacking a nuclear localization signal with nuclear pore complexes (NPCs) in permeabilized HeLa cells. Confocal and wide-field optical images of the nuclear envelope show well-spaced individual NPCs. Specific interactions of capsids with single NPCs are characterized by extended residence times of capsids in the focal volume which are characterized by fluorescence correlation spectroscopy. In addition, single-capsid-tracking experiments using fast wide-field fluorescence microscopy at 50 frames/s allow us to directly observe specific binding via a dual-color co-localization of capsids and NPCs. We find that binding occurs with high probability on the nuclear-pore ring moiety, at 44 ± 9 nm radial distance from the central axis.
Key Words:
Nuclear pore complex, capsids, dual-color experiments, fluorescence correlation spectroscopy, single particle tracking, specific interaction
