Details

Autor(en) / Beteiligte

• Zhao, Pei
• Liu, Qiao
• Miller, W. Allen
• Goss, Dixie J.

Titel

Eukaryotic translation initiation factor 4G (eIF4G) coordinates interactions with eIF4A, eIF4B, and eIF4E in binding and translation of the barley yellow dwarf virus 3′ cap-independent translation element (BTE)

Ist Teil von

• The Journal of biological chemistry, 2017-04, Vol.292 (14), p.5921-5931

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Barley yellow dwarf virus RNA, lacking a 5′ cap and a 3′ poly(A) tail, contains a cap-independent translation element (BTE) in the 3′-untranslated region that interacts with host translation initiation factor eIF4G. To determine how eIF4G recruits the mRNA, three eIF4G deletion mutants were constructed: (i) eIF4G601–1196, containing amino acids 601–1196, including the putative BTE-binding region, and binding domains for eIF4E, eIF4A, and eIF4B; (ii) eIF4G601–1488, which contains an additional C-terminal eIF4A-binding domain; and (iii) eIF4G742–1196, which lacks the eIF4E-binding site. eIF4G601–1196 binds BTE tightly and supports efficient translation. The helicase complex, consisting of eIF4A, eIF4B, and ATP, stimulated BTE binding with eIF4G601–1196 but not eIF4G601–1488, suggesting that the eIF4A binding domains may serve a regulatory role, with the C-terminal binding site having negative effects. eIF4E binding to eIF4G601–1196 induced a conformational change, significantly increasing the binding affinity to BTE. A comparison of the binding of eIF4G deletion mutants with BTEs containing mutations showed a general correlation between binding affinity and ability to facilitate translation. In summary, these results reveal a new role for the helicase complex in 3′ cap-independent translation element-mediated translation and show that the functional core domain of eIF4G plus an adjacent probable RNA-binding domain mediate translation initiation.