An adaptive transposable element insertion in the regulatory region of the EO gene in the domesticated silkworm, Bombyx mori.
An adaptive transposable element insertion in the regulatory region of the EO gene in the domesticated silkworm, Bombyx mori.
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DOI：
10.1093/molbev/msu261
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发表时间：
2014-09
影响因子：
10.7
通讯作者：
Wei Sun;Yi-Hong Shen;Min-Jin Han;Yun Cao;Ze Zhang
中科院分区：
文献类型：
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作者：
Wei Sun;Yi-Hong Shen;Min-Jin Han;Yun Cao;Ze Zhang
虽然有许多研究表明转座元件(TES)在高等生物的适应性进化中起着关键作用，但对其分子机制知之甚少。在本研究中，我们发现了一个插入到家蚕蜕皮酮氧化酶(EO)基因顺式调控区的部分TE(Taguchi)，该基因编码一种降低蜕皮激素(20-羟基蜕皮酮，20E)滴度的关键酶。家蚕(Bombyx Mori)中的TE插入频率较高，达54.24%。家蚕TE插入品系的连锁不均衡性提高。分子群体遗传学分析表明，这种TE插入对家蚕是适宜的。荧光报告实验表明，插入在EO基因顺式调控区的TE作为20E诱导的基因表达增强子发挥作用。进一步的表型生物测定表明，在食物短缺的情况下，插入TE的家蚕比没有插入TE的家蚕表现出更稳定的发育表型。因此，在EO基因顺式调控区插入的TE通过调节20E代谢增加了家蚕个体的发育一致性，部分解释了家蚕驯化发育性状的转变。我们的结果强调了基因表达调控在家养动物发育转变中的特殊作用。
Although there are many studies to show a key role of transposable elements (TEs) in adaptive evolution of higher organisms, little is known about the molecular mechanisms. In this study, we found that a partial TE (Taguchi) inserted in the cis-regulatory region of the silkworm ecdysone oxidase (EO) gene, which encodes a crucial enzyme to reduce the titer of molting hormone (20-hydroxyecdysone, 20E). The TE insertion occurred during domestication of silkworm and the frequency of the TE insertion in the domesticated silkworm (Bombyx mori) is high, 54.24%. The linkage disequilibrium in the TE inserted strains of the domesticated silkworm was elevated. Molecular population genetics analyses suggest that this TE insertion is adaptive for the domesticated silkworm. Luminescent reporter assay shows that the TE inserted in the cis-regulatory region of the EO gene functions as a 20E-induced enhancer of the gene expression. Further, phenotypic bioassay indicates that the silkworm with the TE insertion exhibited more stable developmental phenotype than the silkworm without the TE insertion when suffering from food shortage. Thus, the inserted TE in the cis-regulatory region of the EO gene increased developmental uniformity of silkworm individuals through regulating 20E metabolism, partially explaining transformation of a domestication developmental trait in the domesticated silkworm. Our results emphasize the exceptional role of gene expression regulation in developmental transition of domesticated animals.