Recruitment of the 40S Ribosome Subunit to the 3'-Untranslated Region (UTR) of a Viral mRNA, via the eIF4 Complex, Facilitates Cap-independent Translation

Biblio

Publication Type:

Journal Article

Source:

J Biol Chem, Volume 290, Number 18, p.11268-81 (2015)

ISBN:

1083-351X (Electronic)<br/>0021-9258 (Linking)

Accession Number:

25792742

Abstract:

Barley yellow dwarf virus mRNA, which lacks both cap and poly(A) tail, has a translation element (3'-BTE) in its 3'-UTR essential for efficient translation initiation at the 5'-proximal AUG. This mechanism requires eukaryotic initiation factor 4G (eIF4G), subunit of heterodimer eIF4F (plant eIF4F lacks eIF4A), and 3'-BTE-5'-UTR interaction. Using fluorescence anisotropy, SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) analysis, and toeprinting, we found that (i) 40S subunits bind to BTE (Kd = 350 +/- 30 nm), (ii) the helicase complex eIF4F-eIF4A-eIF4B-ATP increases 40S subunit binding (Kd = 120 +/- 10 nm) to the conserved stem-loop I of the 3'-BTE by exposing more unpaired bases, and (iii) long distance base pairing transfers this complex to the 5'-end of the mRNA, where translation initiates. Although 3'-5' interactions have been recognized as important in mRNA translation, barley yellow dwarf virus employs a novel mechanism utilizing the 3'-UTR as the primary site of ribosome recruitment.

Notes:

Sharma, Sohani Das<br/>Kraft, Jelena J<br/>Miller, W Allen<br/>Goss, Dixie J<br/>G12 MD007599/MD/NIMHD NIH HHS/United States<br/>United States<br/>J Biol Chem. 2015 May 1;290(18):11268-81. doi: 10.1074/jbc.M115.645002. Epub 2015 Mar 19.