Structural Characterization of the Zinc Finger Domain of Cytoplasmic Polyadenylation Element-Binding Protein

Abstract

Cytoplasmic polyadenylation element-binding protein (CPEB) is an important factor in translational regulation of oogenesis, cellular senescence and synaptic plasticity. It does this by regulating a poly(A) tail elongation through interactions with a number of other proteins. The region of mRNA that CPEB binds to is a uracil rich region known as the cytoplasmic polyadenylation element (CPE). The carboxy terminal region of CPEB is composed of three regions that are required for CPE recognition and binding within the 3’ UTR of mRNA. It has two RNA binding domains and a zinc finger motif. The zinc finger region contains six cysteine and two histidine amino acids that are highly conserved throughout many species. The conserved residues suggest the presence of a zinc finger structure containing two zinc ions. The zinc finger region of CPEB does not seem to be homologous with any know zinc fingers. We are currently in the process of structural characterization using NMR techniques.