title: Regulation of the fruit-specific PEP carboxylase SlPPC2 promoter at early stages of tomato fruit development.
abstract: The SlPPC2 phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) gene from tomato (Solanum lycopersicum) is differentially and specifically expressed in expanding tissues of developing tomato fruit. We recently showed that a 1966 bp DNA fragment located upstream of the ATG codon of the SlPPC2 gene (GenBank AJ313434) confers appropriate fruit-specificity in transgenic tomato. In this study, we further investigated the regulation of the SlPPC2 promoter gene by analysing the SlPPC2 cis-regulating region fused to either the firefly luciferase (LUC) or the β-glucuronidase (GUS) reporter gene, using stable genetic transformation and biolistic transient expression assays in the fruit. Biolistic analyses of 5' SlPPC2 promoter deletions fused to LUC in fruits at the 8(th) day after anthesis revealed that positive regulatory regions are mostly located in the distal region of the promoter. In addition, a 5' UTR leader intron present in the 1966 bp fragment contributes to the proper temporal regulation of LUC activity during fruit development. Interestingly, the SlPPC2 promoter responds to hormones (ethylene) and metabolites (sugars) regulating fruit growth and metabolism. When tested by transient expression assays, the chimeric promoter:LUC fusion constructs allowed gene expression in both fruit and leaf, suggesting that integration into the chromatin is required for fruit-specificity. These results clearly demonstrate that SlPPC2 gene is under tight transcriptional regulation in the developing fruit and that its promoter can be employed to drive transgene expression specifically during the cell expansion stage of tomato fruit. Taken together, the SlPPC2 promoter offers great potential as a candidate for driving transgene expression specifically in developing tomato fruit from various tomato cultivars.
authors.affiliation: Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, Institut National de la Recherche Agronomique, Villenave d'Ornon, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Guillet
authors.forename: Mourad A M
authors.initials: MA
authors.lastname: Aboul-Soud
authors.forename: Aline
authors.initials: A
authors.lastname: Le Menn
authors.forename: Nicolas
authors.initials: N
authors.lastname: Viron
authors.forename: Anne
authors.initials: A
authors.lastname: Pribat
authors.forename: Véronique
authors.initials: V
authors.lastname: Germain
authors.forename: Daniel
authors.initials: D
authors.lastname: Just
authors.forename: Pierre
authors.initials: P
authors.lastname: Baldet
authors.forename: Patrick
authors.initials: P
authors.lastname: Rousselle
authors.forename: Martine
authors.initials: M
authors.lastname: Lemaire-Chamley
authors.forename: Christophe
authors.initials: C
authors.lastname: Rothan
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D017930:Genes, Reporter; D007438:Introns; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development*; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic
chemical_list: D017931:DNA Primers; D010940:Plant Proteins