Seed-specific expression of sesame microsomal oleic acid desaturase is controlled by combinatorial properties between negative cis-regulatory elements in the SeFAD2 promoter and enhancers in the 5′-UTR intron

Abstract

The regulation of genes involved in primary lipid metabolism in plants is much less well understood than that in many other pathways in plant biology. In the investigation reported here, we have characterized transcriptional regulatory mechanisms controlling seed-specific FAD2 expression in sesame (Sesamum indicum). FAD2 codes for extra-plastidial FAD2 desaturase, which catalyzes the conversion of oleic acid to linoleic acid. Promoter analysis of the sesame FAD2 gene (SeFAD2) using the beta-glucuronidase (GUS) reporter system demonstrated that the - 660 to - 180 promoter region functions as a negative cis-element in the seed-specific expression of the SeFAD2 gene. Sesame and Arabidopsis FAD2 genes harbor one large intron within their 5'-untranslated region. These introns conferred up to 100-fold enhancement of GUS expression in transgenic Arabidopsis tissues as compared with intron-less controls. Prerequisite cis-elements for the SeFAD2 intron-mediated enhancement of gene expression and the promoter-like activity of SeFAD2 intron were identified. SeFAD2 transcripts were induced by abscisic acid (ABA) in developing sesame seeds, and the - 660 to - 548 and - 179 to - 53 regions in the SeFAD2 promoter were implicated in ABA-responsive signaling. Theses observations indicate that an intron-mediated regulatory mechanism is involved in controlling not only the seed-specific expression of the SeFAD2 gene but also the expression of plant FAD2 genes, which are essential for the synthesis of polyunsaturated fatty acids.

Trans-regulation of the expression of the transcription factor MtHAP2-1 by a uORF controls root nodule development

“…5B-D, lanes 1,2). The higher GUS expression level observed with the 35S:5ЈLS-AS-GUS compared with the 35S:GUS construct is probably due to intronmediated enhancement, a phenomenon that has been reported to confer up to 100-fold enhancement of gene expression (Kim et al 2006). No effect on GUS expression was detected when uORF1 was coexpressed with 35S:GUS-3ЈUTR (data not shown) or when uORF2 or uORF3 were used for coinfiltration, thus indicating a clear specificity for uORF1 action on the MtHAP2-1 5ЈLS (Supplemental Fig.…”

Genome Wide Analysis of Fatty Acid Desaturation and Its Response to Temperature

“…gz package. Polymorphisms are marked relative to the start of transcription in Col-0 (Kim et al, 2006).…”

Efficiency for increasing seed oil content using WRINKLED1 and DGAT1 under the control of two seed-specific promoters, FAE1 and Napin

“…Tissue-specific promoters, such as leaf-, phloem-, root-, fruit-, pollen-, flowerand green tissue-specific promoters, have also been used for such purposes (van Tunen et al 1988;Pear et al 1989;Yamamoto et al 1991;Rogers et al 2001;Husebye et al 2002;Gowik et al 2004;Bakhsh et al 2011). In particular, several seed-specific promoters, including Napin, USP, FAE1, oleosin, and SeFAD2 have been widely used to modify seed oil composition and content (Josefsson et al 1987;Rossak et al 2001;Suh et al 2002;Schmid et al 2005;Kim et al 2006;. In this study, the activities of the two seed-specific promoters, AtFAE1 from Arabidopsis Fatty Acid Elongase 1 gene and the BnNapin from Brassica napus seed storage protein gene, were compared by the expression of AtWRI1 and AtDGAT1 genes under the control of those promoters in Arabidopsis.…”