A cis-element in the 3'-untranslated region of IkappaB-zeta mRNA governs its stimulus-specific expression.
IkappaB-zeta, an essential transcriptional regulator in inflammatory reactions, is induced by microbial substances that stimulate Toll-like receptors and interleukin (IL)-1beta but not by tumor necrosis factor (TNF)-alpha, via specific mRNA stabilization. Here, we attempted to identify a cis-element in IkappaB-zeta mRNA that confers the specific induction. To evaluate the activities of various fragments in the post-transcriptional regulation, we constructed unique reporter plasmids, in which a fragment was inserted downstream of a destabilized luciferase cDNA transcribed by the SV40 early enhancer/promoter. In NIH3T3 cells, a reporter plasmid harboring IkappaB-zeta mRNA exhibited elevated luciferase activity following stimulation with lipopolysaccharide or IL-1beta, but not TNF-alpha, indicating the stimulus-specificity. We found that a 165-nucleotide fragment in the 3'-untranslated region conferred the specific induction. Stimulus-specific induction of IkappaB-zeta was observed by transfection of full-length IkappaB-zeta mRNA, but not of a mRNA without the fragment. Thus, this sequence is essential for the stimulus-specific induction of IkappaB-zeta via a post-transcriptional regulatory mechanism.
Watanabe
Satoshi
S
Department of Molecular and Cellular Biochemistry, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
Takeshige
Koichiro
K
Muta
Tatsushi
T
D020413:3' Untranslated Regions / Q000235:genetics*; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics; D051379:Mice; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation
D020413:3' Untranslated Regions; D048868:Adaptor Proteins, Signal Transducing; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; C485947:Nfkbiz protein, mouse; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D008156:Luciferases