title: Real-time dynamics of RNA polymerase II clustering in live human cells.
abstract: Transcription is reported to be spatially compartmentalized in nuclear transcription factories with clusters of RNA polymerase II (Pol II). However, little is known about when these foci assemble or their relative stability. We developed a quantitative single-cell approach to characterize protein spatiotemporal organization, with single-molecule sensitivity in live eukaryotic cells. We observed that Pol II clusters form transiently, with an average lifetime of 5.1 (± 0.4) seconds, which refutes the notion that they are statically assembled substructures. Stimuli affecting transcription yielded orders-of-magnitude changes in the dynamics of Pol II clusters, which implies that clustering is regulated and plays a role in the cell's ability to effect rapid response to external signals. Our results suggest that transient crowding of enzymes may aid in rate-limiting steps of gene regulation.
authors.affiliation: Functional Imaging of Transcription, CNRS UMR8197, Ecole Normale Supérieure, Institut de Biologie de l'ENS, IBENS, Paris, 75005 France.
authors.forename: Ibrahim I
authors.initials: II
authors.lastname: Cisse
authors.forename: Ignacio
authors.initials: I
authors.lastname: Izeddin
authors.forename: Sebastien Z
authors.initials: SZ
authors.lastname: Causse
authors.forename: Lydia
authors.initials: L
authors.lastname: Boudarene
authors.forename: Adrien
authors.initials: A
authors.lastname: Senecal
authors.forename: Leila
authors.initials: L
authors.lastname: Muresan
authors.forename: Claire
authors.initials: C
authors.lastname: Dugast-Darzacq
authors.forename: Bassam
authors.initials: B
authors.lastname: Hajj
authors.forename: Maxime
authors.initials: M
authors.lastname: Dahan
authors.forename: Xavier
authors.initials: X
authors.lastname: Darzacq
mesh_terms: D045744:Cell Line, Tumor; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D010880:Piperidines / Q000494:pharmacology; D012319:RNA Polymerase II / Q000378:metabolism*; D059010:Single-Cell Analysis / Q000379:methods; D013997:Time Factors; D061805:Transcription Elongation, Genetic / Q000187:drug effects; D014158:Transcription, Genetic
chemical_list: D005419:Flavonoids; D010880:Piperidines; C077990:alvocidib; D012319:RNA Polymerase II