The seed-specific oleosin promoter of Brassica juncea : Cloning, characterization and identification of the novel and divergent antisense open reading frame^†

The highly seed-specific promoter of the oleosin gene in Brassica juncea has been cloned by PCR. Analysis of the 940 bp promoter region has identified the following cis-acting elements: the untranslated leader sequence; two AT-rich regions; two GC-rich regions; one RY box; three 7 bp repeats in two directions; four sequences very similar to the abscisic acid responsive element (ABRE); one element common to the ∆⁹-stearoyl desaturase and two putative transcription initiation sites with associated upstream TATA boxes. Interestingly, a novel antisense open reading frame (ORF2) has been detected far upstream of the promoter. This ORF shares significant homology to divergent genes, including some of unrelated species. The significance of various cis elements and of the novel ORF for specific regulation of the oleosin gene expression and its utility in the transgenic plant research are discussed.