44 ABA特異的グルコシルトランスフェラーゼをコードする遺伝子のクローニング

概要

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The occurrence of glucosylated ABA such as ABA-O-glucoside or ABA glucosyl ester in many plant species has been reported. Their physiological roles, however, remain unknown. Under the hypothesis that the glucosylation participates in the regulation of endogenous level of free ABA, we tried to isolated cDNAs which encode gucosyl transferases(GTase) catalizing the glucosylation of ABA. PCR was carried out using mRNA prepared from the ABA treated azuki epicotyls and the degenerated primers for the conserved region in many GTase homologs. To facilitate the selection of the target genes, we focused to screen the ABA-upregulated UDP-GTase genes. We detected one by northern hybridization analysis using the PCR products as probes. We cloned the full length cDNA from the library prepared from ABA treated azuki epicotyls. The putative amino acid sequence encoded by the cDNA showed 30-44% identity with known homologs. The GST-fused recombinant protein was expressed in E. coli and showed the activity glucosylating ABA when incubated with tritiated ABA and UDP-glucose. The study on the substrate specificity of the protein is under way.
植物化学調節学会の論文
2000-11-02