Cai Shiyu, Xue Lina, Tao Ziling, Li Fengxiu, Liu Qiao, Wan Wen, Jiang Jihong, Li Ludan, Cao Xiaoying
The Key Laboratory of Biotechnology for Medicinal and Edible Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, China.
Plant Mol Biol. 2025 Jul 31;115(4):97. doi: 10.1007/s11103-025-01626-1.
Paclitaxel is an important natural anticancer drug. Its biosynthesis is very complex and 18 enzymes likely involved have been characterized. However, the regulatory mechanism of these enzyme genes still remains to be elucidated. Here we identified a novel transcription factor in the MYC family of Taxus chinensis TcJAMYC5 function in paclitaxel biosynthesis. TcJAMYC5 was highly expressed in the roots and regulated by MeJA. Transient overexpression of TcJAMYC5 in T. chinensis cambial meristematic cells resulted in a significant increase in paclitaxel and bacctin III content and upregulated expression of nearly all of paclitaxel biosynthesis related genes except T13αOH. Suppression of TcJAMYC5 expression in cambial meristematic cells resulted in a significant decrease in paclitaxel content. TcJAMYC5 could bind to promoters of paclitaxel biosynthesis pathway enzyme genes TASY, DBTNBT and T5αH for directly activating their expression. Taken together, we conclude that TcJAMYC5 is an activator that improves the accumulation of paclitaxel in T. chinensis through a MeJA-medicated signaling pathway.
紫杉醇是一种重要的天然抗癌药物。其生物合成非常复杂，已鉴定出可能涉及的18种酶。然而，这些酶基因的调控机制仍有待阐明。在此，我们在红豆杉的MYC家族中鉴定出一种新的转录因子TcJAMYC5，其在紫杉醇生物合成中发挥作用。TcJAMYC5在根中高表达，并受茉莉酸甲酯（MeJA）调控。在红豆杉形成层分生细胞中瞬时过表达TcJAMYC5，导致紫杉醇和巴卡亭III含量显著增加，除T13αOH外，几乎所有紫杉醇生物合成相关基因的表达均上调。在形成层分生细胞中抑制TcJAMYC5的表达，导致紫杉醇含量显著降低。TcJAMYC5可以与紫杉醇生物合成途径酶基因TASY、DBTNBT和T5αH的启动子结合，直接激活它们的表达。综上所述，我们得出结论，TcJAMYC5是一种激活剂，通过MeJA介导的信号通路提高红豆杉中紫杉醇的积累。
