title: Structure of the genomic DNA encoding cucumber ascorbate oxidase and its expression in transgenic plants.
abstract: Genomic DNA (Aso1) encoding the ascorbate oxidase (ASO) of cucumber (Cucumis sativas) was cloned and sequenced. From a comparison of the sequences of Aso1 and its cDNA [Ohkawa et al. Proc. Natl. Acad. Sci. USA 86 (1989) 1239-1243], it was concluded that Aso1 consisted of four exons and three introns. In the 5'-flanking region, sequence motif resembling a TATA box and a CAAT box, were found 124 and 218 bp upstream, respectively, from the start codon. Sites of initiation of transcription, determined by primer extension, were the A and G residues located 90 and 93 bp, respectively, upstream from the initiation codon. ASO was abundant in cucumber fruits and stems. The 5'-flanking region, placed upstream of the structural gene of β-glucuronidase (GUS), expressed the GUS activity in cucumber plants in a transient expression assay after introduction of DNA with a particle gun. High-level GUS expression was found in stems of transgenic tobacco plants harboring Aso1 promoter-GUS chimeric gene.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Osaka University, Suita, 565, Osaka, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Ohkawa
authors.forename: T
authors.initials: T
authors.lastname: Ohya
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.forename: H
authors.initials: H
authors.lastname: Nozawa
authors.forename: Y
authors.initials: Y
authors.lastname: Nishi
authors.forename: N
authors.initials: N
authors.lastname: Okada
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Takano
authors.forename: A
authors.initials: A
authors.lastname: Shinmyo