Tissue-dependent variation in the expression of elongation factor-1 alpha isoforms: isolation and characterisation of a cDNA encoding a novel variant of human elongation-factor 1 alpha.

A novel isoform of human elongation factor-1 alpha (EF-1 alpha 2) has been characterised. It shows a high similarity to other EF-1 alpha proteins, especially to a rat EF-1 alpha variant and it has all the characteristics of a functional EF-1 alpha protein. The pattern of expression of both EF-1 alpha 2 and EF-1 alpha was analysed in different human tissues. This showed that the two proteins were differentially expressed, EF-1 alpha 2 was expressed in brain, heart, skeletal muscle and in the transformed cell lines AMA and K14, but was undetectable in other tissues and in both primary and transformed human fibroblasts. EF-1 alpha was expressed in brain, placenta, lung, liver, kidney, pancreas and in all the cell lines that we have analysed but barely detectable in heart and skeletal muscle.