Oscillating kissing stem–loop interactions mediate 5′ scanning-dependent translation by a viral 3′-cap-independent translation element
Year: 2006
Type: article
Abstract: The 3'-untranslated regions (UTRs) of a group of novel uncapped viral RNAs allow efficient translation initiation at the 5'-proximal AUG. A well-characterized model is the Barley yellow dwarf virus class of cap-independent translation elements (BTE). It facilitates translation by forming kissing stem-loops between the BTE in the 3'-UTR and a BTE-complementary loop in the 5'-UTR. Here we investigate the mechanisms of the long-distance interaction and ribosome entry on the RNA. Upstream AUGs or 5'-extensions of the 5'-UTR inhibit translation, indicating that, unlike internal ribosome entry sites in many viral RNAs, the BTE relies on 5'-end-dependent ribosome scanning. Cap-independent translation occurs when the kissing sites are moved to different regions in either UTR, including outside of the BTE. The BTE can even confer cap-independent translation when fused to the 3'-UTR of a reporter RNA harboring dengue virus sequences that cause base-pairing between the 3'- and 5'-ends. Thus, the BTE serves as a functional sensor to detect sequences capable of long-distance base-pairing. We propose that the kissing interaction is repeatedly disrupted by the scanning ribosome and re-formed in an oscillating process that regulates ribosome entry on the RNA.
Source: RNA
DOI: 10.1261/rna.115606
Institutions: Iowa State University, University of California, Berkeley
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2100998316