Cis and trans-acting elements involved in the activation of Arabidopsis thaliana Al gene encoding the translation elongation factor EF-lα

Abstract

In A. thallana the translation elongation factor EF-1α is encoded by a small multigenic family of four members (A1-A4). The A1 gene promoter has been dissected and examined in a translent expression system using the GUS reporter gene. Deletion analysis has shown that several elements are involved In the activation process. One cls-acting domain, the TEF 1 box, has been accurately mapped 100 bp upstream of the transcription initiation site. This domain is the target for trans-acting factors identified in nuclear extracts prepared from A. thallana. Homologles are found between the TEF 1 box and sequences present at the same location within the A2, A3 and A4 promoters. This observation, together with those obtained from gel retardation assays performed using DNA fragments from the A4 promoter, suggest that the activation process mediated by the TEF 1 element is conserved among the A. thallana EF-1α genes. Analysis of nearly full length cDNA clones has shown that in addition to a single intron located within the coding region, the Al gene contains a second intron located within the 5′ non coding region. Such an intron is also present within the A2, A3 and A4 genes. This 5′ intervening sequence appears to be essential to obtain a maximum GUS activity driven by the A1 gene promoter. © 1991 Oxford Uiversity Press.