Oscillating kissing stem-loop interactions mediate 5' scanning-dependent translation by a viral 3'-cap-independent translation element.

Aurelie M. Rakotondrafara, Charlotta Polacek, Eva Harris, W. Allan Miller

Research output: Contribution to journalJournal articleResearchpeer-review

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.
Keyword: long-distance RNA interactions translation initiation kissing stem–loop; Luteovirus dengue virus
Original languageEnglish
JournalR N A
Volume12
Issue number10
Pages (from-to)1893-1906
ISSN1355-8382
DOIs
Publication statusPublished - 2006
Externally publishedYes

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