Translational control of beta2-adrenergic receptor mRNA by T-cell-restricted intracellular antigen-related protein.
Cellular expression of the beta(2)-adrenergic receptor (beta(2)-AR) is suppressed at the translational level by 3'-untranslated region (UTR) sequences. To test the possible role of 3'-UTR-binding proteins in translational suppression of beta(2)-AR mRNA, we expressed the full-length 3'-UTR or the adenylate/uridylate-rich (A+U-rich element (ARE)) RNA from the 3'-UTR sequences of beta(2)-AR in cell lines that endogenously express this receptor. Reversal of beta(2)-adrenergic receptor translational repression by retroviral expression of 3'-UTR sequences suggested that ARE RNA-binding proteins are involved in translational suppression of beta(2)-adrenergic receptor expression. Using a 20-nucleotide ARE RNA from the receptor 3'-UTR as an affinity ligand, we purified the proteins that bind to these sequences. T-cell-restricted intracellular antigen-related protein (TIAR) was one of the strongly bound proteins identified by this method. UV-catalyzed cross-linking experiments using in vitro transcribed 3'-UTR RNA and glutathione S-transferase-TIAR demonstrated multiple binding sites for this protein on beta(2)-AR 3'-UTR sequences. The distal 340-nucleotide region of the 3'-UTR was identified as a target RNA motif for TIAR binding by both RNA gel shift analysis and immunoprecipitation experiments. Overexpression of TIAR resulted in suppression of receptor protein synthesis and a significant shift in endogenously expressed beta(2)-AR mRNA toward low molecular weight fractions in sucrose gradient polysome fractionation. Taken together, our results provide the first evidence for translational control of beta(2)-AR mRNA by TIAR.
Kandasamy
Karthikeyan
K
Department of Medicine and Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina 29425-2221, USA.
Joseph
Kusumam
K
Subramaniam
Kothandharaman
K
Raymond
John R
JR
Tholanikunnel
Baby G
BG
D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000502:physiology*; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D020413:3' Untranslated Regions; D017931:DNA Primers; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D018343:Receptors, Adrenergic, beta-2; C076751:TIAL1 protein, human