An octopine synthase enhancer element directs tissue-specific expression and binds ASF-1, a factor from tobacco nuclear extracts.
We have investigated the expression pattern conferred by a cis-regulatory element (-212 to -154) from the upstream region of the octopine synthase (ocs) gene in transgenic tobacco plants. Analysis of beta-glucuronidase expression driven by the ocs regulatory element revealed a pattern that is tissue-specific and developmentally regulated. In young seedlings, expression is confined primarily to root tips. In older seedlings, expression is stronger and becomes apparent also in the shoot apex. Insertion of a 16-base pair palindromic sequence (-193 to -178), which is included in the regulatory element, into an rbcS promoter results in the expression of rbcS in roots. The 16-base pair palindrome binds activation sequence factor (ASF)-1, a factor from tobacco nuclear extracts that interacts with the sequence between -83 to -63, designated as activation sequence (as)-1, of the cauliflower mosaic virus 35S promoter [Lam et al. (1989). Proc. Natl. Acad. Sci. USA 86, in press]. The in vivo expression patterns and in vitro binding properties of the ocs palindromic sequence are remarkably similar to those of the as-1 element of the cauliflower mosaic virus 35S promoter. These results suggest the involvement of ASF-1 in the transcriptional regulation of the ocs promoter and the 35S promoter.
Fromm
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H
Laboratory of Plant Molecular Biology, Rockefeller University, New York, New York 10021-6399.
Katagiri
F
F
Chua
N H
NH
D000594:Amino Acid Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D015971:Gene Expression Regulation, Enzymologic; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D012091:Repetitive Sequences, Nucleic Acid; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D004247:DNA; D000594:Amino Acid Oxidoreductases; C021903:D-octopine dehydrogenase; D005966:Glucuronidase