title: Nuclear organization and dynamics of 7SK RNA in regulating gene expression.
abstract: Noncoding RNAs play important roles in various aspects of gene regulation. We have identified 7SK RNA to be enriched in nuclear speckles or interchromatin granule clusters (IGCs), a subnuclear domain enriched in pre-mRNA processing factors. 7SK RNA, in association with HEXIM 1 and 2, is involved in the inhibition of transcriptional elongation by RNA polymerase II. Inhibition occurs via sequestration of the active P-TEFb kinase complex (CDK 9 and Cyclin T1/T2a/b or K) that is involved in phosphorylating the C-terminal domain of RNA polymerase II. Our results demonstrate that knock-down of 7SK RNA, by specific antisense oligonucleotides, results in the mislocalization of nuclear speckle constituents in a transcription-dependent manner, and the transcriptional up-regulation of a RNA polymerase II transcribed reporter gene locus. Furthermore, 7SK RNA transiently associates with a stably integrated reporter gene locus upon transcriptional down-regulation and its presence correlates with the efficient displacement of P-TEFb constituents from the locus. Our results suggest that 7SK RNA plays a role in modulating the available level of P-TEFb upon transcriptional down-regulation by sequestering its constituents in nuclear speckles.
authors.affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
authors.forename: Kannanganattu V
authors.initials: KV
authors.lastname: Prasanth
authors.forename: Matthew
authors.initials: M
authors.lastname: Camiolo
authors.forename: Grace
authors.initials: G
authors.lastname: Chan
authors.forename: Vidisha
authors.initials: V
authors.lastname: Tripathi
authors.forename: Laurence
authors.initials: L
authors.lastname: Denis
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nakamura
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hübner
authors.forename: David L
authors.initials: DL
authors.lastname: Spector
mesh_terms: D056906:Cyclin T / Q000378:metabolism; D042863:Cyclin-Dependent Kinase 9 / Q000235:genetics / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D016376:Oligonucleotides, Antisense; D042925:Positive Transcriptional Elongation Factor B / Q000235:genetics / Q000378:metabolism*; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012342:RNA, Small Nuclear / Q000235:genetics* / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000235:genetics / Q000502:physiology; D015533:Transcriptional Activation
chemical_list: D056906:Cyclin T; C476123:HEXIM1 protein, human; C501428:HEXIM2 protein, human; D016376:Oligonucleotides, Antisense; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear; D014157:Transcription Factors; D042925:Positive Transcriptional Elongation Factor B; D042863:Cyclin-Dependent Kinase 9; D012319:RNA Polymerase II