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Elife. 2014 Jun 12;3. doi: 10.7554/eLife.02230.

Single-molecule tracking in live cells reveals distinct target-search strategies of transcription factors in the nucleus.

Author information

1
Functional Imaging of Transcription, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Inserm U1024, and CNRS UMR 8197, Paris, France.
2
Laboratoire de Physique Théorique de la Matière Condensée, CNRS UMR 7600, Université Pierre et Marie Curie, Paris, France.
3
Cell Biology of Transcription, Institut de Biologie de l'École Normale Supérieure (IBENS) CNRS UMR 8197, Paris, France.
4
Laboratoire Kastler Brossel, CNRS UMR 8552, Departement de Physique et Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Paris, France.

Abstract

Gene regulation relies on transcription factors (TFs) exploring the nucleus searching their targets. So far, most studies have focused on how fast TFs diffuse, underestimating the role of nuclear architecture. We implemented a single-molecule tracking assay to determine TFs dynamics. We found that c-Myc is a global explorer of the nucleus. In contrast, the positive transcription elongation factor P-TEFb is a local explorer that oversamples its environment. Consequently, each c-Myc molecule is equally available for all nuclear sites while P-TEFb reaches its targets in a position-dependent manner. Our observations are consistent with a model in which the exploration geometry of TFs is restrained by their interactions with nuclear structures and not by exclusion. The geometry-controlled kinetics of TFs target-search illustrates the influence of nuclear architecture on gene regulation, and has strong implications on how proteins react in the nucleus and how their function can be regulated in space and time.

KEYWORDS:

biophysics; cell biology; human; nuclear organization; single-molecule tracking; structural biology; target search; transcription regulation

PMID:
24925319
PMCID:
PMC4095940
DOI:
10.7554/eLife.02230
[Indexed for MEDLINE]
Free PMC Article

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