Take our Survey

Reference: Shibuya T, et al. (2006) Mutational analysis of human eIF4AIII identifies regions necessary for exon junction complex formation and nonsense-mediated mRNA decay. RNA 12(3):360-74

Reference Help

Abstract


The exon junction complex (EJC) is deposited on mRNAs by the process of pre-mRNA splicing and is a key effector of downstream mRNA metabolism. We previously demonstrated that human eIF4AIII, which is essential for nonsense-mediated mRNA decay (NMD), constitutes at least part of the RNA-binding platform anchoring other EJC components to the spliced mRNA. To determine the regions of eIF4AIII that are functionally important for EJC formation, for binding to other EJC components, and for NMD, we now report results of an extensive mutational analysis of human eIF4AIII. Using GFP-, GST- or Flag-fusions of eIF4AIII versions containing site-specific mutations or truncations, we analyzed subcellular localizations, protein-protein interactions, and EJC formation in vivo and in vitro. We also tested whether mutant proteins could rescue NMD inhibition resulting from RNAi depletion of endogenous eIF4AIII. Motifs Ia and VI, which are conserved among the eIF4A family of RNA helicases (DEAD-box proteins), are crucial for EJC formation and NMD, as is one eIF4AIII-specific region. An additional eIF4AIII-specific motif forms part of the binding site for MLN51, another EJC core component. Mutations in the canonical Walker A and B motifs that eliminate RNA-dependent ATP hydrolysis by eIF4AIII in vitro are of no detectable consequence for EJC formation and NMD activation. Implications of these findings are discussed in the context of other recent results and a new structural model for human eIF4AIII based on the known crystal structure of Saccharomyces cerevisiae eIF4AI.

Reference Type
Journal Article | Research Support, Non-U.S. Gov't | Research Support, N.I.H., Extramural | In Vitro
Authors
Shibuya T, Tange TO, Stroupe ME, Moore MJ
Primary Lit For
Additional Lit For
Review For

Interaction Annotations


Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Type Assay Annotation Action Modification Phenotype Source Reference

Gene Ontology Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Gene Gene Ontology Term Qualifier Aspect Method Evidence Source Assigned On Annotation Extension Reference

Phenotype Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.

Gene Phenotype Experiment Type Mutant Information Strain Background Chemical Details Reference

Regulation Annotations


Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.

Regulator Target Experiment Assay Construct Conditions Strain Background Reference