title: Inhibition of NF-kappaB stabilizes gadd45alpha mRNA.
abstract: Growth arrest- and DNA damage-inducible protein alpha (gadd45alpha) is an important regulator for cell cycle, genomic stability, and cell apoptosis. In the present report, we demonstrated that NF-kappaB inhibition due to Ikkbeta deficiency enhanced the stability of gadd45alpha mNRA. Using embryo fibroblast cells derived from wild type (wt) or Ikkbeta gene knockout (Ikkbeta(-/-)) mice, reverse transcription-polymerase chain reaction revealed a three- to fourfold increase of gadd45alpha mRNA in Ikkbeta(-/-) cells compared with wt cells. The deficiency in Ikkbeta substantially decreased basal NF-kappaB activity and increased accumulation of reactive oxygen species (ROS). However, such deficiency had no effect on the basal expression or activity of Akt, FoxO3a, p53, and c-myc that regulate the transcription of gadd45alpha gene positively or negatively. Analysis of gadd45alpha mRNA stability showed a ROS-dependent increase in the half-life of gadd45alpha mRNA in Ikkbeta(-/-) cells. Immunoprecipitation experiments indicated an increased binding of a RNA stabilizing protein, nucleolin, to gadd45alpha mRNA in Ikkbeta(-/-) cells. The binding of nucleolin to gadd45alpha mRNA could be prevented by the antioxidant, N-acetyl-cysteine. Thus, these data are the first to suggest that inhibition of Ikkbeta-NF-kappaB signaling up-regulates the expression of gadd45alpha mNRA through a post-transcriptional, rather than a transcriptional, mechanism.
authors.affiliation: Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai 200031, PR China.
authors.forename: Xue
authors.initials: X
authors.lastname: Zheng
authors.forename: Yadong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yu-Quan
authors.initials: YQ
authors.lastname: Chen
authors.forename: Vince
authors.initials: V
authors.lastname: Castranova
authors.forename: Xianglin
authors.initials: X
authors.lastname: Shi
authors.forename: Fei
authors.initials: F
authors.lastname: Chen
mesh_terms: D000818:Animals; D004249:DNA Damage; D003609:Dactinomycin / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D017930:Genes, Reporter; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051550:I-kappa B Kinase; D015151:Immunoblotting; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010750:Phosphoproteins / Q000096:biosynthesis / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism; D017382:Reactive Oxygen Species; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D019076:Transgenes; D015854:Up-Regulation; D000097642:GADD45 Proteins; D000097796:Nucleolin
chemical_list: D003609:Dactinomycin; D006861:Hydrogen Peroxide; D051550:I-kappa B Kinase; D047908:Intracellular Signaling Peptides and Proteins; D008156:Luciferases; D016328:NF-kappa B; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D017382:Reactive Oxygen Species; D000097642:GADD45 Proteins; D000097796:Nucleolin; C496564:Chuk protein, mouse; C496562:Ikbkb protein, mouse; C496566:Ikbke protein, mouse