Reduced Toxicity of Trichothecenes, Isotrichodermol, and Deoxynivalenol, by Transgenic Expression of the Tri101 3-O-Acetyltransferase Gene in Cultured Mammalian FM3A Cells

Abstract

In trichothecene-producing fusaria, isotrichodermol (ITDol) is the first intermediate with a trichothecene skeleton. In the biosynthetic pathway of trichothecene, a 3-O-acetyltransferase, encoded by Tri101, acetylates ITDol to a less-toxic intermediate, isotrichodermin (ITD). Although trichothecene resistance has been conferred to microbes and plants transformed with Tri101, there are no reports of resistance in cultured mammalian cells. In this study, we found that a 3-O-acetyl group of trichothecenes is liable to hydrolysis by esterases in fetal bovine serum and FM3A cells. We transfected the cells with Tri101 under the control of the MMTV-LTR promoter and obtained a cell line G3 with the highest level of C-3 acetylase activity. While the wild-type FM3A cells hardly grew in the medium containing 0.40 μM ITDol, many G3 cells survived at this concentration. The IC50 values of ITDol and ITD in G3 cells were 1.0 and 9.6 μM, respectively, which were higher than the values of 0.23 and 3.0 μM in the wild-type FM3A cells. A similar, but more modest, tendency was observed in deoxynivalenol and 3-acetyldeoxynivalenol. Our findings indicate that the expression of Tri101 conferred trichothecene resistance in cultured mammalian cells.

Reactive Oxygen Species Metabolism and Diacetoxyscirpenol Biosynthesis Modulation in Potato Tuber Inoculated with Ozone-Treated Fusarium sulphureum

“…After that, under the catalysis of multifunctional P450 monooxygenase encoded by Tri4 gene, isotriol is synthesized by four-step oxygenation reaction. The Tri101 gene encodes isotriol to form isotrichodermin (ITD) [37,38]. The results of this study indicate that ozone treatment downregulated the expressions of Tri4, Tri5, Tri10, Tri6, and Tri101 genes, which led to lower DIA biosynthesis.…”

Loop Evolutionary Patterns Shape Catalytic Efficiency of TRI101/201 for Trichothecenes: Insights into Protein–Substrate Interactions

“…Therefore, most detoxification strategies focused on these sites. Several enzymatic detoxification methods have been developed for these groups, including de-epoxidation at positions C12 and C13, oxidation, , isomerization, acetylation, , and glycosylation , at C3.…”

Introduction to the Toxins Special Issue on Toxicological Effects of Mycotoxin on Target Cells

“…Wild-type FM3A cells and G3 cells (transfected cells with Tri101) were exposed to ITDol, isotrichodermin ITD and trichothecenes (DON, 3-ADON) by Tanaka et al [11]. It was observed that wild-type FM3A cells hardly grew, while G3 cells survived and cytotoxicity was lower in G3 cells exposed to ITDol and ITD than in wild-type FM3A cells.…”