The 3' untranslated region of manganese superoxide dismutase RNA contains a translational enhancer element.
A redox-sensitive protein that binds to the 3' untranslated region (UTR) of manganese superoxide dismutase (MnSOD) RNA has been described previously [Fazzone, H., Wangner, A., and Clerch, L. B. (1993) J. Clin. Invest. 92, 1278-1281; Chung, D. J., and Clerch, L. B. (1997) Am. J. Physiol. 16, L714-L719]. In the present study, cross-competition gel retardation and RNase H assays were used to identify a 41-base region located 111 bases downstream of the stop codon as the 3' UTR cis element involved in protein binding. The base sequence of this region is approximately 75% conserved among the 3' UTRs of rat, mouse, cow, and human MnSOD mRNAs at approximately the same distance downstream of the stop codon. The role of this protein-binding region in RNA translation was assessed in an in vitro rabbit reticulocyte lysate system. Translation of MnSOD RNA from which the 3' UTR element was deleted decreased 60% compared with translation of MnSOD RNA containing the 3' UTR cis element. In the presence of a specific competitor oligoribonucleotide that inhibits MnSOD RNA protein-binding activity, translation of MnSOD RNA containing the 3' UTR was decreased by 65%. Thus, both the cis element and RNA protein-binding activity were required for more efficient translation of the MnSOD. An analysis of ribosomal profiles suggests the MnSOD RNA-binding protein participates in the formation of the translation initiation complex. When MnSOD RNA-binding activity was inhibited, initiation complex formation was decreased by 50%. From the data obtained in this study, we propose that the 3' UTR cis element of MnSOD through its interaction with MnSOD RNA-binding protein may function as a translational enhancer.
Chung
D J
DJ
Lung Biology Laboratory, Department of Physiology and Biophysics, Georgetown University School of Medicine, Washington, D.C. 20007, USA.
Wright
A E
AE
Clerch
L B
LB
D020413:3' Untranslated Regions / Q000235:genetics* / Q000502:physiology; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002458:Cell Fractionation; D004742:Enhancer Elements, Genetic; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010442:Peptide Chain Initiation, Translational / Q000235:genetics; D010449:Peptide Mapping; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000378:metabolism / Q000502:physiology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D012156:Reticulocytes / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism
D020413:3' Untranslated Regions; D016601:RNA-Binding Proteins; D012313:RNA; D013482:Superoxide Dismutase