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The untranslated leader sequences of the barley lipoxygenase 1 (Lox1) gene confers embryo-specific expression

Rouster, J., Mechelen, J. van., Cameron-Mills, V.
The plant journal 1998 v.15 no.3 pp. 435-440
seed germination, Hordeum vulgare, assays, jasmonic acid, linoleate 13S-lipoxygenase, transgenic plants, plasmid vectors, transcription (genetics), gene expression, aleurone cells, reporter genes, enzyme activity, promoter regions, beta-glucuronidase, leaves, seed development
The barley lipoxygenase 1 (Lox1) gene encodes a protein expressed in embryos during grain development and germination and in leaves after methyl-jasmonate (MeJA) treatment. Transient gene expression assays in germinating barley embryos were used to identify cis-regulatory elements involved in the embryo-specific expression of the Lox1 gene. Analysis of transcriptional or translational fusions between Lox1 5' upstream sequences and the gusA reporter gene indicated that the 5'-untranslated leader sequence was involved in embryo-specific expression. Replacement of the leader sequence from the aleurone-specific Chi26 gene with the Lox1 leader sequence resulted in a chimeric gene expressed at high levels in embryo as well as in aleurone cells. Insertion of the Lox1 leader sequence between the 35S minimum promoter (A domain -90/+8) and the gusA reporter gene greatly enhanced promoter activity in a tissue-specific manner. Deletion/replacement analysis of the Lox1 leader sequence, combined with transient expression in germinating embryos and in vitro transcription/translation assays, suggests that the Lox1 leader sequence contains cis-elements regulating qualitative (tissue-specific) and quantitative gene expression.