Park EH, et al. (2011) Multiple elements in the eIF4G1 N-terminus promote assembly of eIF4G1*PABP mRNPs in vivo. EMBO J 30(2):302-16
Abstract: eIF4G is the scaffold subunit of the eIF4F complex, whose binding domains for eIF4E and poly(A)-binding protein (PABP) are thought to enhance formation of activated eIF4F*mRNA*PABP complexes competent to recruit 43S pre-initiation complexes. We found that the RNA-binding region (RNA1) in the N-terminal domain (NTD) of yeast eIF4G1 can functionally substitute for the PABP-binding segment to rescue the function of an eIF4G1-459 mutant impaired for eIF4E binding. Assaying RNA-dependent PABP-eIF4G association in cell extracts suggests that RNA1, the PABP-binding domain, and two conserved elements (Box1 and Box2) between these segments have overlapping functions in forming native eIF4G*mRNA*PABP complexes. In vitro experiments confirm the role of RNA1 in stabilizing eIF4G-mRNA association, and further indicate that RNA1 and Box1 promote PABP binding, in addition to RNA binding, by the eIF4G1 NTD. Our findings indicate that PABP-eIF4G association is only one of several interactions that stabilize eIF4F*mRNA complexes, and emphasize that closed-loop mRNP formation via PABP-eIF4G interaction is non-essential in vivo. Interestingly, two other RNA-binding regions in eIF4G1 have critical functions downstream of eIF4F*mRNA assembly.
|Status: Published||Type: Journal Article||PubMed ID: 21139564|
Topics addressed in this paper
Number of different genes curated to this paper: 3
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