title: Actin-dependent intranuclear repositioning of an active gene locus in vivo.
abstract: Although bulk chromatin is thought to have limited mobility within the interphase eukaryotic nucleus, directed long-distance chromosome movements are not unknown. Cajal bodies (CBs) are nuclear suborganelles that nonrandomly associate with small nuclear RNA (snRNA) and histone gene loci in human cells during interphase. However, the mechanism responsible for this association is uncertain. In this study, we present an experimental system to probe the dynamic interplay of CBs with a U2 snRNA target gene locus during transcriptional activation in living cells. Simultaneous four-dimensional tracking of CBs and U2 genes reveals that target loci are recruited toward relatively stably positioned CBs by long-range chromosomal motion. In the presence of a dominant-negative mutant of beta-actin, the repositioning of activated U2 genes is markedly inhibited. This supports a model in which nuclear actin is required for these rapid, long-range chromosomal movements.
authors: Department of Cell Biology, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA. mirek.dundr@rosalindfranklin.edu
authors: Miroslav
authors: M
authors: Dundr
authors: Jason K
authors: JK
authors: Ospina
authors: Myong-Hee
authors: MH
authors: Sung
authors: Sam
authors: S
authors: John
authors: Madhvi
authors: M
authors: Upender
authors: Thomas
authors: T
authors: Ried
authors: Gordon L
authors: GL
authors: Hager
authors: A Gregory
authors: AG
authors: Matera
mesh_terms: D000199:Actins / Q000378:metabolism / Q000502:physiology*; D002875:Chromosomes / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D020541:Coiled Bodies / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000032:analysis; D012342:RNA, Small Nuclear / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000032:analysis; D015533:Transcriptional Activation
chemical_list: D000199:Actins; D008164:Luminescent Proteins; D012342:RNA, Small Nuclear; D011993:Recombinant Fusion Proteins; C405484:U2 small nuclear RNA