Date of Degree
Dixie J. Goss
Frida E. Kleiman
Biochemistry | Biophysics | Molecular Biology
Protein RNA Interaction, Virus RNA Translation
Barley Yellow Dwarf Virus (BYDV) lacks a 5’ (7-methyl guanosine) cap as well as a 3’poly A tail. Like many plant viruses, BYDV contains a cap independent translation element (CITE) in the 3’ untranslated region of the viral mRNA. BTE (Barley Yellow Dwarf Virus like cap-independent translation element) is one of the well characterized CITEs. BTE mediated translation primarily depends on eukaryotic initiation factor eIF4G. BTE binds to eIF4G; however, the details of BTE initiated translation are still unclear. Three eIF4G deletion mutants with different domain organization were used to investigate BTE interaction with eIF4G: eIF4G601-1196 is the eIF4G fragment containing amino acid residues from 601 to 1196, including binding domains for eIF4E, central eIF4A, eIF4B and the possible BTE binding region; eIF4G601-1488 is a longer fragment with one additional C-terminal eIF4A binding domain; eIF4G742-1196 is a shorter deletion mutant lacking the eIF4E binding sequence. eIF4G601-1196 binds BTE as efficiently as wild type eIF4G and supports translation. Translation initiation factor eIF4A and eIF4B with ATP (helicase complex) stimulate eIF4G601-1196 binding with BTE but not eIF4G601-1488, suggesting that the helicase complex function relies on the eIF4G central eIF4A binding domain, not the C-terminal eIF4A binding domain. This suggests that, similar to human eIF4G, the wheat eIF4A binding site may serve a regulatory role. eIF4E, upon binding with eIF4G mutants which have the eIF4E binding region, significantly increases the binding to BTE. This indicates that the smaller eIF4G mutant has a more flexible structure that can be positively influenced by eIF4E.
Zhao, Pei, "The Interaction Between Eukaryotic Translation Initiation Factor eIF4G and 3’ Cap Independent Translation Element of Barley Yellow Dwarf Virus Is Affected by Multiple Initiation Factors" (2016). CUNY Academic Works.