Molecular cloning and characterization of the Arabidopsis thaliana α-subunit of elongation factor 1B

Using a PCR-based approach,,ve have isolated two Arabidopsis thaliana cDNA clones (alpha 1 and alpha 2) encoding the alpha-subunit of translation elongation factor 1B (eEF1B alpha). They encode open reading frames of 228 and 224 amino acids respectively, with extensive homology to eEF1B alpha subunits from different organisms, particularly in the C-terminal half of the protein, They both lack a conserved phosphorylation site that has been implicated in regulating nucleotide exchange activity, Using a plasmid shuffling experiment, me demonstrated that both al and alpha 2 clones are able to complement a mutant yeast strain deficient for the eEF1Ba subunit, This provides evidence that Arabidopsis encodes at least two functional isoforms of this subunit, termed eEF1B alpha 1 and eEF1B alpha 2. A third cDNA clone was isolated that appeared to result from an alternative splicing event of the eEF1B alpha 1 gene. (C) 1999 Federation of European Biochemical Societies.