报告题目：“Gene regulation of the biosynthesis of Vinca alkaloids (长春花碱), a class of pharmaceutically valuable natural products”
报告人：袁凌教授(美国肯塔基大学)
报告时间：2011年6月29日上午9:00
报告地点：生科院1号楼523室
内容简介：
Catharanthus roseus（长春花）produces a large array of terpenoid indole alkaloids (TIAs；萜类吲哚碱) that are an important source of natural or semi-synthetic anticancer drugs. Biosynthesis of TIAs is tissue-specific and induced by certain phytohormones and fungal elicitors, indicating the involvement of a complex transcriptional control network. However, the transcriptional regulation of the TIA pathway is poorly understood. I will provide background information on our limited understanding of TIA pathway gene regulation and describe a C. roseus WRKY transcription factor, CrWRKY1, that is preferentially expressed in roots and induced by phytohormones jasmonate, gibberellic acid and ethylene. Overexpression of CrWRKY1 in C. roseus hairy roots up-regulated several key TIA pathway genes, especially tryptophan decarboxylase (TDC; 色氨酸脱羧酶), as well as transcriptional repressors ZCT1, ZCT2 and ZCT3. However, CrWRKY1 overexpression repressed the transcriptional activators, ORCA2, ORCA3 and CrMYC2. Overexpression of a dominant-repressive form of CrWRKY1, created by fusing the SRDX-repressor domain to CrWRKY1, resulted in down-regulation of TDC and ZCTs but up-regulation of ORCA3 and CrMYC2. CrWRKY1 bound to the W-box elements of the TDC promoter in electrophoretic mobility shift, yeast one-hybrid and C. roseus protoplast assays. Up-regulation of TDC increased TDC activity, tryptamine concentration and resistance to 4-methyl tryptophan (4-甲基色氨酸) inhibition of CrWRKY1 hairy roots. Compared to control roots, CrWRKY1 hairy roots accumulated up to 3-fold higher levels of serpentine【蛇根碱（利血平）】. The preferential expression of CrWRKY1 in roots and its interaction with transcription factors including ORCA3, CrMYC2 and ZCTs may play a key role in determining the root-specific accumulation of serpentine in C. roseus plants.
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2011-06-24 16:20:28
来源：http://sky.scnu.edu.cn/content.asp?c=11&m=2&n=1010&j=&todo=showinfo
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