Chen Haijiang, Mao Lijuan, Zhao Nan, Xia Chenyang, Liu Jian, Kubicek Christian P, Wu Wenneng, Xu Su, Zhang Chulong
College of Food and Pharmaceutical Engineering, Guiyang University, Guiyang, China.
Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Front Microbiol. 2021 Oct 25;12:731425. doi: 10.3389/fmicb.2021.731425. eCollection 2021.
Trichodermin, a trichothecene first isolated in species, is a sesquiterpenoid antibiotic that exhibits significant inhibitory activity to the growth of many pathogenic fungi such as , , and by inhibiting the peptidyl transferase involved in eukaryotic protein synthesis. Trichodermin has also been shown to selectively induce cell apoptosis in several cancer cell lines and thus can act as a potential lead compound for developing anticancer therapeutics. The biosynthetic pathway of trichodermin in has been identified, and most of the involved genes have been functionally characterized. An exception is , which encodes a putative acetyltransferase. Here, we report the identification of a gene cluster that contains seven genes expectedly involved in trichodermin biosynthesis (, , , , , , and ) in the trichodermin-producing endophytic fungus . As in , is not included in the cluster. Functional analysis provides evidence that TRI3 acetylates trichodermol, the immediate precursor, to trichodermin. Disruption of gene eliminated the inhibition to by culture filtrates and significantly reduced the production of trichodermin but not of trichodermol. Both the inhibitory activity and the trichodermin production were restored when native gene was reintroduced into the disruption mutant. Furthermore, a His-tag-purified TRI3 protein, expressed in , was able to convert trichodermol to trichodermin in the presence of acetyl-CoA. The disruption of also resulted in lowered expression of both the upstream biosynthesis genes and the regulator genes. Our data demonstrate that encodes an acetyltransferase that catalyzes the esterification of the C-4 oxygen atom on trichodermol and thus plays an essential role in trichodermin biosynthesis in this fungus.
木霉菌素是一种于[具体年份]首次从[某种物种]中分离出的单端孢霉烯族毒素，是一种倍半萜类抗生素，通过抑制参与真核生物蛋白质合成的肽基转移酶，对多种致病真菌如[具体真菌名称1]、[具体真菌名称2]和[具体真菌名称3]的生长表现出显著的抑制活性。木霉菌素还被证明能在几种癌细胞系中选择性地诱导细胞凋亡，因此可作为开发抗癌治疗药物的潜在先导化合物。木霉菌素在[具体菌种]中的生物合成途径已被确定，且大多数相关基因已进行了功能表征。一个例外是[基因名称]，它编码一种假定的乙酰转移酶。在此，我们报告在产木霉菌素的内生真菌[具体真菌名称]中鉴定出一个基因簇，该基因簇包含七个预期参与木霉菌素生物合成的基因（[基因名称1]、[基因名称2]、[基因名称3]、[基因名称4]、[基因名称5]、[基因名称6]和[基因名称7]）。与[具体菌种]情况一样，[基因名称]不包含在该基因簇中。功能分析提供了证据表明TRI3将直接前体木霉菌醇乙酰化为木霉菌素。[基因名称]基因的破坏消除了[具体真菌名称]培养滤液对[具体对象]的抑制作用，并显著降低了木霉菌素的产量，但木霉菌醇的产量未受影响。当将天然的[基因名称]基因重新导入破坏突变体时，抑制活性和木霉菌素产量均得以恢复。此外，在[具体表达系统]中表达的His标签纯化的TRI3蛋白，在乙酰辅酶A存在的情况下能够将木霉菌醇转化为木霉菌素。[基因名称]的破坏还导致上游生物合成[基因名称]基因和调节基因的表达降低。我们的数据表明，[基因名称]编码一种乙酰转移酶，该酶催化木霉菌醇上C-4氧原子的酯化反应，因此在该真菌的木霉菌素生物合成中起关键作用。
