THE FIRST INTRON OF THE ARABIDOPSIS-THALIANA GENE CODING FOR ELONGATION-FACTOR 1-BETA CONTAINS AN ENHANCER-LIKE ELEMENT

Genomic and cDNA clones coding for elongation factor-1 beta (eEF-1 bet a) from Arabidopsis thaliana (At) were isolated and characterized. eEF -1 beta was found to be encoded by a single-copy At gene. Chimeric gen es fusing the promoter and the 5' untranslated region of the At eEF-1 beta gene to the gus reporter gene were constructed and used to study the expression of this gene in transgenic tobacco plants. Interestingl y, it was found that the first intron of this gene is required for hig h levels of expression. Experiments using chimeric promoters showed th at an enhancer-like element is present in the first intron of At eEF-1 beta. Gel-shift assays were used to demonstrate that this intron is s pecifically bound by putative transcription factors present in nuclear protein extracts.