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Nitric oxide‐p38 MAPK signaling stabilizes mRNA through AU‐rich element‐dependent and ‐independent mechanisms
Author(s) -
Wang Shuibang,
Zhang Jianhua,
Zhang Yi,
Kern Steven,
Danner Robert L.
Publication year - 2008
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0907641
Subject(s) - biology , untranslated region , microbiology and biotechnology , au rich element , messenger rna , three prime untranslated region , luciferase , transfection , mapk/erk pathway , rna binding protein , reporter gene , gene expression , gene , signal transduction , biochemistry
Regulation of mRNA stability by p38 MAPK has been linked to adenosine‐uridine‐rich elements (AURE) within the 3′‐untranslated region (3′UTR) of mRNA. Using microarrays, we previously found that AURE‐containing mRNA is over‐represented among transcripts up‐regulated by NO • , an activator of p38 MAPK. Here, we investigated NO • ‐induced mRNA stabilization of specific AURE‐containing genes to determine the sequence specificity and protein‐binding interactions associated with this effect. IL‐8, TNF‐α, and p21/Waf1 3′UTRs were inserted into a luciferase (LUC) reporter gene system and found to decrease LUC activity and mRNA half‐life in transfected THP‐1 cells. The inhibitory effect of these 3′UTRs on LUC expression inversely correlated with the number of AUUUA motifs. Sequence truncation of the IL‐8 3′UTR revealed that two segments, one with AURE sites and another without, contributed to mRNA destabilization. NO • activation of p38 MAPK increased LUC activity and mRNA half‐life for reporter constructs that contained either of these IL‐8 3′UTR segments. AURE‐dependent and ‐independent NO • effects were blocked by p38 MAPK inhibition, and AURE‐dependent effects were also blocked by site‐directed mutagenesis of AUUUA sites. Two proteins, HuR and heterogeneous nuclear ribonucleoprotein A0, were identified, which bound to the AURE‐containing region of exogenous and endogenous IL‐8 mRNA in a NO • ‐p38 MAPK‐dependent manner. These results demonstrate that NO • ‐p38 MAPK signaling can stabilize mRNA via AURE‐dependent and ‐independent mechanisms.