Characterisation of a cDNA Encoding Chick Eukaryotic Translation Initiation Factor-2β

A full length cDNA for the β subunit of chick (Gallus gallus) eukaryotic translation initiation factor-2 is described. This cDNA was isolated by screening a chick cDNA library with a probe derived via differential display of developing chick heart tissue. Up-regulated expression of eIF-2β mRNA was confirmed by reverse Northern dot blot analysis. eIF-2β, together with eIF-2α and eIF-2γ, comprise subunits of a complex that promotes the binding of methionyl-tRNA to ribosomes during the initiation of protein translation. The nucleotide sequence of the chick eIF-2β cDNA predicts a protein of 334 amino acids that has 95%, 93%, 56% and 37% sequence identity with rabbit, human, drosophila and yeast eIF-2β, respectively. The deduced eIF-2p protein contains a number of functional motifs and domains consistent with the putative function of this protein; these include a potential C2-C2 zinc-finger binding domain, three polylysine regions, and three acidic regions.