Premium
CRM 1‐Mediated Nucleocytoplasmic Export of Adrenergic Receptor mRNAs: Role in mRNA Stability and Agonist‐Mediated Down‐Regulation
Author(s) -
Machida Curtis A.
Publication year - 2006
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/fasebj.20.5.lb70-b
Subject(s) - messenger rna , nuclear export signal , agonist , receptor , downregulation and upregulation , chemistry , microbiology and biotechnology , transfection , cytoplasm , biology , gene , biochemistry , cell nucleus
The β 1 ‐adrenergic receptor (β 1 ‐AR) mRNAs are post‐transcriptionally regulated at the level of mRNA stability and undergo accelerated agonist‐mediated degradation. Treatment of cells with leptomycin B, an inhibitor of the nuclear export receptor CRM 1, results in a dramatic enhancement of β 1 ‐AR mRNA stability. To assess whether CRM 1 or other nuclear export receptors play direct roles in β 1 ‐AR mRNA down‐regulation, we used cell‐permeable peptides containing the leucine‐rich nuclear export signal (NES) recognized by CRM 1, to serve as inhibitors of CRM 1‐mediated nuclear export. When DDT 1 MF2 transfectants ectopically expressing β 1 ‐AR mRNAs were concurrently treated with isoproterenol and peptide inhibitors, only the co‐addition of the NES inhibitor reversed the isoproterenol‐induced reduction of β 1 ‐AR mRNA levels. Using UV‐crosslinking/immunoprecipitation analyses, we have verified the interaction of CRM 1 – HuR complexes with the β 1 ‐AR mRNA. CRM 1 is nearly absent in neonatal rat cortical neurons (RCNs), which express abundant β 1 ‐AR mRNAs but do not undergo agonist‐mediated β 1 ‐AR mRNA down‐regulation. Upon transfection with a CRM 1 expression recombinant, the neonatal RCNs exhibit agonist‐mediated β 1 ‐AR mRNA down‐regulation and decreased β 1 ‐AR transcript stability. We conclude that agonist‐mediated β 1 ‐AR mRNA down‐regulation and degradation utilize the CRM 1‐mediated nucleocytoplasmic export pathway for deposition of transcripts into the cytoplasm. Supported by NIH MH071317 and MH63137.