Structure of the RNA Specialized Translation Initiation Element that Recruits eIF3 to the 5'-UTR of c-Jun.
Walker, M.J., Shortridge, M.D., Albin, D.D., Cominsky, L.Y., Varani, G.(2020) J Mol Biol 432: 1841-1855
- PubMed: 31953146 
- DOI: https://doi.org/10.1016/j.jmb.2020.01.001
- Primary Citation of Related Structures:  
6MXQ, 6NOA - PubMed Abstract: 
Specialized translation initiation is a novel form of regulation of protein synthesis, whereby RNA structures within the 5'-UTR regulate translation rates of specific mRNAs. Similar to internal ribosome entry sites (IRESs), specialized translation initiation requires the recruitment of eukaryotic initiation factor 3 (eIF3), but also requires cap recognition by eIF3d, a new 5'-m 7 GTP recognizing protein. How these RNA structures mediate eIF3 recruitment to affect translation of specific mRNAs remains unclear. Here, we report the nuclear magnetic resonance (NMR) structure of a stem-loop within the c-JUN 5' UTR recognized by eIF3 and essential for specialized translation initiation of this well-known oncogene. The structure exhibits similarity to eIF3 recognizing motifs found in hepatitis C virus (HCV)-like IRESs, suggesting mechanistic similarities. This work establishes the RNA structural features involved in c-JUN specialized translation initiation and provides a basis to search for small molecule inhibitors of aberrant expression of the proto-oncogenic c-JUN.
Organizational Affiliation: 
Department of Chemistry, University of Washington, Seattle, WA, USA 98195.