title: The DEAD-box RNA helicase DDX1 interacts with RelA and enhances nuclear factor kappaB-mediated transcription.
abstract: DEAD-box RNA helicases constitute the largest family of RNA helicases and are involved in many aspects of RNA metabolism. In this study, we identified RelA (p65), a subunit of nuclear factor-kappaB (NF-kappaB), as a cellular co-factor of DEAD-box RNA helicase DDX1, through mammalian two hybrid system and co-immunoprecipitation assay. Additionally, confocal microscopy and chromatin immunoprecipitation assays confirmed this interaction. In NF-kappaB dependent reporter gene assay, DDX1 acted as a co-activator to enhance NF-kappaB-mediated transcription activation. The functional domains involved were mapped to the carboxy terminal transactivation domain of RelA and the amino terminal ATPase/helicase domain of DDX1. The DDX1 trans-dominant negative mutant lacking ATP-dependent RNA helicase activity lost it transcriptional inducer activity. Moreover, depletion of endogenous DDX1 by specific small interfering RNAs significantly reduced NF-kappaB-dependent transcription. Taken together, the results suggest that DDX1 may play an important role in NF-kappaB-mediated transactivation, and revelation of this regulatory pathway may help to explore the novel mechanisms for regulating NF-kappaB transcriptional activity.
authors.affiliation: State Key Laboratory of Virology and Modern Virology Research Centre, College of Life Sciences, Wuhan University, Wuhan 430072, PR China.
authors.forename: Musarat
authors.initials: M
authors.lastname: Ishaq
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Wu
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Mu
authors.forename: Ji'an
authors.initials: J
authors.lastname: Pan
authors.forename: Jiajie
authors.initials: J
authors.lastname: Hu
authors.forename: Tao
authors.initials: T
authors.lastname: Hu
authors.forename: Qiong
authors.initials: Q
authors.lastname: Fu
authors.forename: Deyin
authors.initials: D
authors.lastname: Guo
mesh_terms: D002460:Cell Line; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D014158:Transcription, Genetic / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D016328:NF-kappa B; D021122:Protein Subunits; D053487:DEAD-box RNA Helicases