title: 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).
abstract: 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.
authors.affiliation: From the Biochemistry and Chemistry Graduate Programs, Graduate Center, and.|the Department of Chemistry and Biochemistry, Hunter College, City University of New York, New York, New York 10065 and.
authors.forename: Pei
authors.initials: P
authors.lastname: Zhao
authors.affiliation: From the Biochemistry and Chemistry Graduate Programs, Graduate Center, and.|the Department of Chemistry and Biochemistry, Hunter College, City University of New York, New York, New York 10065 and.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Liu
authors.affiliation: the Plant Pathology & Microbiology and.|Biochemistry, Biophysics & Molecular Biology Departments, Iowa State University, Ames, Iowa 50011.
authors.forename: W Allen
authors.initials: WA
authors.lastname: Miller
authors.affiliation: From the Biochemistry and Chemistry Graduate Programs, Graduate Center, and dgoss@hunter.cuny.edu.|the Department of Chemistry and Biochemistry, Hunter College, City University of New York, New York, New York 10065 and.
authors.forename: Dixie J
authors.initials: DJ
authors.lastname: Goss
mesh_terms: D039601:Eukaryotic Initiation Factor-4A / Q000235:genetics / Q000378:metabolism*; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000378:metabolism*; D039603:Eukaryotic Initiation Factor-4G / Q000235:genetics / Q000378:metabolism*; D039642:Eukaryotic Initiation Factors / Q000235:genetics / Q000378:metabolism*; D017793:Luteovirus / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000502:physiology*; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D039561:Eukaryotic Initiation Factor-4E; D039603:Eukaryotic Initiation Factor-4G; D039642:Eukaryotic Initiation Factors; D012367:RNA, Viral; D014764:Viral Proteins; C031799:eIF-4B; D039601:Eukaryotic Initiation Factor-4A; D020365:RNA Helicases
keywords: RNA virus; RNA-protein interaction; protein synthesis; translation initiation factor; translation regulation