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Post‐transcriptional regulation of the AT1 receptor mRNA: identification and functional characterization of the mRNA binding motif
Author(s) -
Nickenig Georg,
Michaelsen Frank,
Müller Cornelius,
Vogel Thomas,
Strehlow Kerstin,
Böhm Michael
Publication year - 2001
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.00-0842fje
Subject(s) - messenger rna , motif (music) , chemistry , microbiology and biotechnology , computational biology , biology , gene , biochemistry , physics , acoustics
The expression of the angiotensin AT1 receptor is regulated predominately via post‐transcriptional mechanisms. Angiotensin II reduces the AT1 receptor mRNA half‐life from approximately 6 to 2 h, as assessed by experiments under transcriptional blockade and by in vitro mRNA decay assays in vascular smooth muscle cells (VSMC). UV light‐treated mRNA‐protein cross‐link assays revealed that the AT1 receptor mRNA interacts with at least six polysomal proteins at its 3′‐end. Multiple mutational studies demonstrated that several binding proteins associated with the AT1 receptor mRNA at bases 2175‐2195. Stimulation of VSMC with angiotensin II significantly enhanced the binding of 50 and 60 kDa proteins to the 3′‐untranslated region of the AT1 receptor mRNA. Transfection decoy assays with AT1 receptor mRNA transcript bases 1864‐2213, 2175‐2213, and 2175‐2195 led to a significantly increased basal expression of AT1 receptor mRNA and inhibited angiotensin II‐induced AT1 receptor mRNA down‐regulation. In vitro decay assays revealed that competition of binding of polysomal proteins to bases 2175‐2195 stabilizes the AT1 receptor mRNA. Polysomal proteins thus bind to the 3′‐untranslated region of the AT1 receptor mRNA at the nucleotide sequence 2175‐2195. This protein‐mRNA interaction is decisively involved in the destabilization of the AT1 receptor mRNA by angiotensin II.