Modulation of immediate early gene expression by tristetraprolin in the differentiation of 3T3-L1 cells.
Tristetraprolin (TTP) is a zinc-finger-containing AU-rich elements (ARE)-binding protein. AREs presented in the 3'untranslated region (UTR) of mRNAs from many proto-oncogenes, cytokines, and growth factors may be targets for regulation of messenger RNA stability. In this study, we observed that many immediate early genes (IEGs) were induced during the early differentiation of 3T3-L1 preadipocytes and their ARE-containing transcripts were degraded rapidly. Immunoprecipitation followed by RT-PCR analysis showed that two of IEG mRNAs, COX-2 (cyclooxygenase-2) and MKP-1 (mitogen-activated protein kinase phosphatase), were the target of TTP. Biotinylated MKP-1 AREs also could bring down TTP and the other ARE-binding protein HuR. RNA EMSA and competition assays showed that each of three AREs located in 3'UTR of MKP-1 mRNA has differential binding affinity to TTP. Sequence analysis of 3'UTR of IEG mRNAs suggested that TTP may prefer binding to UUAUUUAUU sequence. Taken together, our results implied that TTP may target specific ARE-containing IEGs' mRNAs such as COX-2 and MKP-1 mRNAs to modulate their expression post-transcriptionally.
Lin
Nien-Yi
NY
Department and Graduate Institute of Veterinary Medicine, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan.
Lin
Chung-Tien
CT
Chang
Ching-Jin
CJ
D041721:3T3-L1 Cells; D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D054638:Dual Specificity Phosphatase 1 / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D017781:Genes, Immediate-Early / Q000235:genetics*; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D051816:Tristetraprolin / Q000378:metabolism*
D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D051816:Tristetraprolin; C497553:Zfp36 protein, mouse; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse