Molecular and functional characterization of novel furofuran-class lignan glucosyltransferases from Forsythia
Molecular and functional characterization of novel furofuran-class lignan glucosyltransferases from Forsythia
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DOI：
10.5511/plantbiotechnology.27.317
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发表时间：
2010-01-01
影响因子：
1.6
通讯作者：
Satake, Honoo
中科院分区：
文献类型：
--
作者：
Ono, Eiichiro;Kim, Hyun Jung;Satake, Honoo
木脂素是植物次生代谢产物中的一大类，因其具有抗肿瘤和雌激素活性而引起人们的广泛关注。已知连翘属植物产生多种木脂素，例如（-）-matairesinol、（-）-开环异落叶松树脂醇、（+）-松醇和（+）-连翘苷元。大多数此类木脂素以葡糖苷形式积累。然而，它们的糖基化机制在很大程度上仍有待阐明。在这里，我们描述了序列，酶活性，基因表达谱的UDP-糖依赖性糖基转移酶（UGT）从连翘通过反向遗传的方法。连翘UGT蛋白UGT 71 A18在E.大肠杆菌中，优选葡糖基化呋喃类木脂素，包括（+）-松甾醇、（+）-表松甾醇和（+）-叶绿素。此外，重组UGT 71 A18对作为糖基供体的UDP-葡萄糖表现出特异性。基因表达分析表明，UGT 71 A18主要在叶片中表达，在F. koreana中表达，并且与非转化体相比，UGT 71 A18转录物在表达松醇落叶松树脂醇还原酶（PLR）基因的RNAi构建体的转基因细胞培养物中上调。这些结果与PLR-RNAi株系中松醇葡糖苷的显著升高一致。总的来说，目前的数据强烈表明，UGT 71 A18，在一定程度上，是负责呋喃类木脂素，包括（+）-松醇和/或结构上相关的木脂素在体内的葡糖基化。
Lignan is a large class of plant secondary metabolites, which has long attracted pharmacological interest because of its anti-tumor and estrogenic activities. Forsythia plants are known to produce a wide variety of lignans, such as (-)-matairesinol, (-)-secoisolariciresinol, (+)-pinoresinol, and (+)-phillygenin. The majority of such lignans are accumulated in glucoside forms. However, their glucosylation mechanisms largely remain to be elucidated. Here we describe the sequence, enzymatic activities, and gene expression profiles of UDP-sugar dependent-glycosyltransferases (UGT) from Forsythia koreana through a reverse-genetic approach. A Forsythia UGT, UGT71A18 protein, expressed in E. coli, preferentially glucosylated furofuran-class lignans, including (+)-pinoreisnol, (+)-epipinoreisnol, and (+)-phylligenin. Moroeover, the recombinant UGT71A18 exhibited specificity to UDP-glucose as a glycosyl donor. Gene expression analysis revealed that UGT71A18 is expressed predominantly in leaves and the suspension cell culture of F. koreana, and that the UGT71A18 transcript is upregulated in the transgenic cell culture expressing the RNAi construct of the pinoresinol lariciresinol reductase ( PLR) gene, compared to non-transformants. These results are consistent with the remarkable elevation of pinoresinol glucosides in the PLR-RNAi lines. Collectively, the present data strongly suggests that UGT71A18, in part, is responsible for glucosylation of furofuran-class lignans, including (+)-pinoresinol and/or structurally related lignans in vivo.