Identification of cis-acting elements involved in the regulation of the pathogenesis-related gene STH-2 in potato.
We have characterized a genomic clone containing the potato pathogenesis-related genes STH-2 and STH-21. The two genes are found 4 kb apart on the same chromosome and their sequences are highly similar. They present the same transcriptional orientation and are both interrupted by a single intron. A chimaeric gene consisting of 1015 bp of 5'-flanking sequence and part of the first exon of STH-2 fused to the bacterial beta-glucuronidase gene was highly-expressed in tubers of transgenic potato plants after wounding and elicitor treatments. The levels of activity observed in these transgenic plants parallel those observed for the accumulation of STH-2 mRNAs under similar conditions. This indicates that cis-acting elements necessary for the proper activation of the gene are present within 1 kb of 5'-flanking sequences. Functional analysis of 5' deletions of the STH-2/GUS constructs by transient expression in leaf protoplasts revealed the presence of an upstream regulatory sequence between -135 and -52 which contains a TGAC motif, and a possible negative regulatory region between -52 and -28. A factor present in nuclear extracts of wounded potato tubers was found to bind specifically to nucleotides located between -135 to -105, suggesting that this region contains important cis-regulatory elements.
Department of Biochemistry, Université de Montréal, Québec, Canada.
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Matton
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Prescott
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Bertrand
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Camirand
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Brisson
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000302:isolation & purification; D005786:Gene Expression Regulation; D017343:Genes, Plant / Q000235:genetics*; D005966:Glucuronidase / Q000096:biosynthesis; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D015183:Restriction Mapping; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid; D011198:Solanum tuberosum / Q000235:genetics*; D014170:Transformation, Genetic
D004268:DNA-Binding Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C053376:pathogenesis-related proteins, plant; D005966:Glucuronidase