A role for eIF4E on mRNA turnover in procesing bodies

FERRERO PAOLA; LAYANA CARLA; RIVERA POMAR ROLANDO

Tucumán

Congreso; 45th annual meeting- SAIB; 2009

SAIB

A role for eIF4E on mRNA turnover in processing bodies. Ferrero PV, Layana C, Rivera Pomar R. Centro Regional de Estudios Genómicos, UNLP y departamento de Ciencias Básicas y Experimentales, UNNOBA. New  functions for the eukaryotic translation initiation factor eF4E have been recently described in mRNA metabolism, namely nuclear export and ribonucleoprotein complex (RNP) remodelling. RNPs remodelling occurs when mRNAs are translocated from active polysomes to citoplasmic processing bodies (PBs). To elucidate the pathway of RNP remodelling involving eIF4E we have studied the fuctional consequences of the interaction between eIF4E, mRNAs and PBs components in vivo. Drosophila melanogaster eIF4E isoform 1 is present in PBs. We have generated eIF4E mutants on key tryptophan (W) residues by replacing them with alanine (A). W100 and W147 are required for mRNA 5´ cap binding, and W117 is required for protein-protein interactions. We transfected S2 cells with wilde type and mutant eIF4E-1 of variants to evaluate the requeriment for PBs localization. Only the mutation of W117 produced relocalization of eIF4E. Similar resultas were obtainde by mutation of the equivalent W in the mouse eIF4E. Therefore, protein-protein interactions rather than cap binding are required for PBS localization. To determinate whether eIF4E- interaction is required for PBs assembly we mutated the eIF4E-binding sites of eIF4E-Like and me31b, both present in PBs. We will present for the remodelling pathway.