Dynamics of passive and active particles in the cell nucleus

Hameed, F.M.; Rao, Madan; Shivashankar, G.V.

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/5570

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DC Field	Value	Language
dc.contributor.author	Hameed, F.M.	-
dc.contributor.author	Rao, Madan	-
dc.contributor.author	Shivashankar, G.V.	-
dc.date.accessioned	2013-04-26T11:48:00Z	-
dc.date.available	2013-04-26T11:48:00Z	-
dc.date.issued	2012-10	-
dc.identifier.citation	PLoS ONE, 2012, Vol.7, pe45843	en
dc.identifier.issn	1932-6203	-
dc.identifier.issn	1932-6203(Online)	-
dc.identifier.uri	http://hdl.handle.net/2289/5570	-
dc.description	Open Access.	en
dc.description.abstract	Inspite of being embedded in a dense meshwork of nuclear chromatin, gene loci and large nuclear components are highly dynamic at C. To understand this apparent unfettered movement in an overdense environment, we study the dynamics of a passive micron size bead in live cell nuclei at two different temperatures ( and C) with and without external force. In the absence of a force, the beads are caged over large time scales. On application of a threshold uniaxial force (about 10 pN), the passive beads appear to hop between cages; this large scale movement is absent upon ATP-depletion, inhibition of chromatin remodeling enzymes and RNAi of lamin B1 proteins. Our results suggest that the nucleus behaves like an active solid with a finite yield stress when probed at a micron scale. Spatial analysis of histone fluorescence anisotropy (a measure of local chromatin compaction, defined as the volume fraction of tightly bound chromatin) shows that the bead movement correlates with regions of low chromatin compaction. This suggests that the physical mechanism of the observed yielding is the active opening of free-volume in the nuclear solid via chromatin remodeling. Enriched transcription sites at C also show caging in the absence of the applied force and directed movement beyond a yield stress, in striking contrast with the large scale movement of transcription loci at C in the absence of a force. This suggests that at physiological temperatures, the loci behave as active particles which remodel the nuclear mesh and reduce the local yield stress.	en
dc.language.iso	en	en
dc.publisher	Public Library of Science	en
dc.relation.uri	http://dx.doi.org/10.1371/journal.pone.0045843	en
dc.relation.uri	http://adsabs.harvard.edu/abs/2012PLoSO...745843H	en
dc.rights	2012 Public Library of Science	en
dc.title	Dynamics of passive and active particles in the cell nucleus	en
dc.type	Article	en
Appears in Collections:	Research Papers (TP)

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