文章基本信息

标题：Two genes encoding 1-aminocyclopropane-1-carboxylate synthase in zucchini (Cucurbita pepo) are clustered and similar but differentially regulated.
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作者：P L Huang ; J E Parks ; W H Rottmann 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：16
页码：7021-7025
DOI：10.1073/pnas.88.16.7021
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A 17-kilobase (kb) region of the zucchini (Cucurbita pepo) genome has been sequenced and contains two genes, CP-ACC1A and CP-ACC1B, encoding 1-aminocyclopropane-1-carboxylate synthase (ACC synthase; S-adenosyl-L-methionine methylthioadenosine-lyase, EC 4.4.1.14 ). The genes are transcribed convergently and are separated by a 5.7-kb intergenic region. Their coding regions are interrupted by four introns located in identical positions. While the DNA identity in their coding regions is 97%, their 5' and 3' flanking regions are highly divergent. Transcription of CP-ACCIA is rapidly induced by wounding in fruit and etiolated hypocotyls and by indoleacetic acid (IAA)/benzyladenine/LiCl only in fruit tissue. Conditions that induce CP-ACC1B expression have not been found. Protein synthesis inhibition derepresses the expression of CP-ACC1A and other unidentified ACC synthase genes, suggesting that they may be under negative control. The amino acid sequences deduced from the nucleotide sequences of the genes are 493 and 494 residues long with 95% identity. The most notable feature of the amino acid sequence is the presence of 11 of the 12 invariant amino acid residues involved in the binding of the substrate and pyridoxal-5'-phosphate in various aminotransferases. We conclude that ACC synthase is encoded by a multigene family of which certain members are differentially induced by auxin in a tissue-specific manner. Furthermore, ACC synthase, a pyridoxal-containing enzyme, may have an evolutionary relationship with the superfamily of aminotransferases.