Skip Internal Navigation
Members of the Section on Nutrient Control of Gene Expression, headed by Alan Hinnebusch, study mechanisms of transcriptional and translational gene regulation. Recently, they provided evidence that the essential function of the beta subunit of the 5-subunit guanine nucleotide exchange factor eIF2B is to promote binding of the substrate, GDP–bound translation initiation factor 2 (eIF2), for the recycling of eIF2. They also demonstrated that interaction of the poly(A) binding protein (PABP) with eIF4G is dispensable for translation in the presence of the N-terminal RNA–binding domain in eIF4G, implying that mRNA circularization via cap-poly(A) interaction is not fundamentally important in vivo but rather represents only one of several interactions that stabilize eIF4G binding to mRNA. Furthermore, genome-wide analysis revealed that eIF4G is dispensable for the translation of most mRNAs, functioning primarily to boost translation rates several fold. It also plays a modest role in adjusting relative translational efficiencies of mRNAs across the genome.