Li Meiya, Cui Yan, Gan Zhibing, Shi Chunlei, Shi Xianming
MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China.
Analytical Testing Center, Zhejiang Chinese Medical University, Hangzhou 310053, China.
Mar Drugs. 2015 Oct 28;13(11):6620-35. doi: 10.3390/md13116620.
Phytoene synthase (PSY) catalyzes the condensation of two molecules of geranylgeranyl pyrophosphate to form phytoene, the first colorless carotene in the carotenoid biosynthesis pathway. So it is regarded as the crucial enzyme for carotenoid production, and has unsurprisingly been involved in genetic engineering studies of carotenoid production. In this study, the psy gene from Chlorella protothecoides CS-41, designated Cppsy, was cloned using rapid amplification of cDNA ends. The full-length DNA was 2488 bp, and the corresponding cDNA was 1143 bp, which encoded 380 amino acids. Computational analysis suggested that this protein belongs to the Isoprenoid_Biosyn_C1 superfamily. It contained the consensus sequence, including three predicted substrate-Mg(2+) binding sites. The Cppsy gene promoter was also cloned and characterized. Analysis revealed several candidate motifs for the promoter, which exhibited light- and methyl jasmonate (MeJA)-responsive characteristics, as well as some typical domains universally discovered in promoter sequences, such as the TATA-box and CAAT-box. Light- and MeJA treatment showed that the Cppsy expression level was significantly enhanced by light and MeJA. These results provide a basis for genetically modifying the carotenoid biosynthesis pathway in C. protothecoides.
八氢番茄红素合酶（PSY）催化两分子牻牛儿基牻牛儿基焦磷酸缩合形成八氢番茄红素，这是类胡萝卜素生物合成途径中的第一种无色类胡萝卜素。因此，它被视为类胡萝卜素合成的关键酶，不出所料地参与了类胡萝卜素合成的基因工程研究。在本研究中，使用cDNA末端快速扩增技术克隆了来自原壳小球藻CS-41的psy基因，命名为Cppsy。全长DNA为2488 bp，相应的cDNA为1143 bp，编码380个氨基酸。计算分析表明，该蛋白属于类异戊二烯生物合成_C1超家族。它包含共有序列，包括三个预测的底物-Mg(2+)结合位点。还克隆并鉴定了Cppsy基因启动子。分析揭示了启动子的几个候选基序，这些基序表现出对光和茉莉酸甲酯（MeJA）的响应特性，以及在启动子序列中普遍发现的一些典型结构域，如TATA框和CAAT框。光和MeJA处理表明，光和MeJA显著提高了Cppsy的表达水平。这些结果为对原壳小球藻的类胡萝卜素生物合成途径进行基因改造提供了依据。
