The mRNA Closed-loop Model: The Function of PABP and PABP-interacting Proteins in mRNA Translation

Translational control is an important means by whichcells govern gene expression. It provides a rapid responseto growth and proliferation stimuli and plays a role incontrolling feedback mechanisms in the cell. In systemswith little or no transcriptional control (e.g., reticulocytesand oocytes), translation is the predominant mode of regulation of gene expression (for review, see Mathews et al.2000). Initiation, the rate-limiting step of translation, isoften the target of translational control. All nuclear-transcribed eukaryotic mRNAs possess a 5′ cap (m7GpppN,where m is a methyl group and N is any nucleotide), andmost possess a 3′ poly(A) tail. The focus of this paper isthe role of the poly(A) tail and the poly(A)-binding protein (PABP) in translation initiation. Such an analysis requires a brief introduction of translation initiation and itscontrol...