The Human Elongation Factor 1 A-2 Gene (EEF1A2): Complete Sequence and Characterization of Gene Structure and Promoter Activity

Abstract

The eukaryotic elongation factor 1 A (eEF1A, formerly EF1α) is a key factor in protein synthesis, where it promotes the transfer of aminoacylated tRNAs to the A site of the ribosome. Two differentially expressed isoforms of eEF1A, designated eEF1A-1 and eEF1A-2, are found in mammals. Here we report the isolation and sequencing of the gene (HGMW-approved symbol EEF1A2) coding for the human eEF1A-2 isoform. Furthermore, we characterize the gene structure and the activity of the promoter. Isolation of overlapping clones from human libraries revealed that the human eEF1A-2 gene spans approximately 10 kb and consists of eight exons. The intron–exon boundaries of human EEF1A2 and EEF1A1 are conserved, yet the gene of the eEF1A-2 isoform is larger than the eEF1A-1 gene because of enlarged introns. Primer extension analysis identified the predominant transcription start site 166 bp upstream of the AUG codon. The start site maps to an adenine located within a consensus initiator element. Sequencing of a 2-kb 5′-flanking promoter region revealed no TATA element. However, several putative cis-regulatory elements were discovered. The 5′-promoter activity was characterized by transient transfection experiments. Progressive deletions of the upstream promoter region defined a minimal promoter region, ranging from −16 to +92, that is sufficient to drive transcription.