title: BRD4 coordinates recruitment of pause release factor P-TEFb and the pausing complex NELF/DSIF to regulate transcription elongation of interferon-stimulated genes.
abstract: RNA polymerase II (Pol II) and the pausing complex, NELF and DSIF, are detected near the transcription start site (TSS) of many active and silent genes. Active transcription starts when the pause release factor P-TEFb is recruited to initiate productive elongation. However, the mechanism of P-TEFb recruitment and regulation of NELF/DSIF during transcription is not fully understood. We investigated this question in interferon (IFN)-stimulated transcription, focusing on BRD4, a BET family protein that interacts with P-TEFb. Besides P-TEFb, BRD4 binds to acetylated histones through the bromodomain. We found that BRD4 and P-TEFb, although not present prior to IFN treatment, were robustly recruited to IFN-stimulated genes (ISGs) after stimulation. Likewise, NELF and DSIF prior to stimulation were hardly detectable on ISGs, which were strongly recruited after IFN treatment. A shRNA-based knockdown assay of NELF revealed that it negatively regulates the passage of Pol II and DSIF across the ISGs during elongation, reducing total ISG transcript output. Analyses with a BRD4 small-molecule inhibitor showed that IFN-induced recruitment of P-TEFb and NELF/DSIF was under the control of BRD4. We suggest a model where BRD4 coordinates both positive and negative regulation of ISG elongation.
authors.affiliation: Program in Genomics of Differentiation, NICHD, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Mira C
authors.initials: MC
authors.lastname: Patel
authors.forename: Maxime
authors.initials: M
authors.lastname: Debrosse
authors.forename: Matthew
authors.initials: M
authors.lastname: Smith
authors.forename: Anup
authors.initials: A
authors.lastname: Dey
authors.forename: Walter
authors.initials: W
authors.lastname: Huynh
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Sarai
authors.forename: Tom D
authors.initials: TD
authors.lastname: Heightman
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Tamura
authors.forename: Keiko
authors.initials: K
authors.lastname: Ozato
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001381:Azepines / Q000494:pharmacology; D002460:Cell Line; D042863:Cyclin-Dependent Kinase 9 / Q000378:metabolism; D016899:Interferon-beta / Q000378:metabolism*; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D042925:Positive Transcriptional Elongation Factor B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012319:RNA Polymerase II; D034741:RNA, Small Interfering; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D014230:Triazoles / Q000494:pharmacology; D000092468:Bromodomain Containing Proteins
chemical_list: D001381:Azepines; D042863:Cyclin-Dependent Kinase 9; D016899:Interferon-beta; D009687:Nuclear Proteins; D042925:Positive Transcriptional Elongation Factor B; D012319:RNA Polymerase II; D034741:RNA, Small Interfering; D014157:Transcription Factors; D014230:Triazoles; C561695:(+)-JQ1 compound; C486694:Brd4 protein, mouse; D000092468:Bromodomain Containing Proteins; C582414:DSIF protein, mouse; C582413:NELF protein, mouse; C467972:Cdk9 protein, mouse