Functional characterization of the horizontally transferred 4,5-DOPA extradiol dioxygenase gene in the domestic silkworm, Bombyx mori
Functional characterization of the horizontally transferred 4,5-DOPA extradiol dioxygenase gene in the domestic silkworm, Bombyx mori
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家蚕水平转移 4,5-DOPA 外二醇双加氧酶基因的功能表征
DOI：
10.1111/imb.12558
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发表时间：
2019
影响因子：
2.6
通讯作者：
Zhang Z
中科院分区：
文献类型：
--
作者：
Wang C F;Sun W;Zhang Z
4，5-DOPA双加氧酶（多达）是甜菜色素生物合成途径中的关键酶。先前的研究表明多达存在于植物、真菌和细菌中。利用最新的数据，我们发现家蚕和其他鳞翅目昆虫的DODA基因（BmDODA）最有可能是从真菌水平转移的。同线性分析表明，BmDODA 1与其它鳞翅目昆虫的DODA基因是同源的，而BmDODA 2是一个旁系同源基因。为了探讨DODA在鳞翅目昆虫中的功能，我们首先研究了BmDODA 1的表达模式。在此基础上，我们对BmDODA 1基因进行了外源表达，并检测了其裂解4，5-DOPA环的活性，计算了其动力学参数。我们发现BmDODA 1基因的转录水平受家蚕败血症芽孢杆菌和大肠杆菌的显著诱导，因此BmDODA基因在家蚕体内的水平转移可能参与了多巴代谢，并有助于该物种的抗菌活性。我们的研究结果提供了真菌和动物之间的功能性水平基因转移（HGT）的一个有据可查的例子，并扩大了我们对真核生物之间HGT的了解。
4,5‐DOPA dioxygenase (DODA) is a crucial enzyme in the biosynthetic pathway of betalain. Previous studies have shown that DODA is present in plants, fungi and bacteria. Using updated data, here we show thatDODAgenes (BmDODA) in the domestic silkworm (Bombyx mori) and other lepidopteran insects are most likely to be horizontally transferred from fungi. A synteny analysis indicated thatBmDODA1is orthologous to other lepidopteranDODAsand thatBmDODA2is a paralogous gene. To explore the function ofDODAin Lepidoptera, we first examined the expression patterns of BmDODA1.BmDODA1showed high transcriptional and translational levels in the midgut and head. Then, we exogenously expressed theBmDODA1gene, detected 4,5‐DOPA ring‐cleaving activity and calculated the kinetic parameters of the recombinant BmDODA1. We found that the transcription levels ofBmDODA1were significantly induced by the pathogensBacillus bombyseptieusandEscherichia coli.Thus, the horizontal transfer of theBmDODAgene in the silkworm may be involved in dopa metabolism and contribute to antimicrobial activity in this species. Our results provide a documented example of functional horizontal gene transfer (HGT) between fungi and animals and expand our knowledge of HGT amongst eukaryotes.