The sequence of Locusta RXR, homologous to Drosophila Ultraspiracle, and its evolutionary implications
The sequence of Locusta RXR, homologous to Drosophila Ultraspiracle, and its evolutionary implications
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DOI：
10.1007/s004270050290
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发表时间：
1999-09-01
影响因子：
2.4
通讯作者：
Ball, EE
中科院分区：
文献类型：
--
作者：
Hayward, DC;Bastiani, MJ;Ball, EE
细胞对类固醇激素的反应是由核受体介导的，核受体通过调节转录发挥作用。在果蝇中，昆虫蜕皮激素的受体20-羟基蜕皮酮是由蜕皮酮受体和超阿司匹林(USP)蛋白组成的异二聚体。节肢动物USPS及其脊椎动物同源物维甲酸X受体(RXR)家族的DNA结合域是高度保守的。然而，配体结合结构域序列分为两个不同的组。其中一组由全变态高等昆虫目双翅目和鳞翅目成员的序列组成，另一组由脊椎动物、螃蟹和扁虱的序列组成。本文报道了半变态直翅目蝗虫的RXR/USP序列。蝗虫的RXR/USP配基结合域明显属于脊椎动物-螃蟹-扁虱类，而不是双翅目-鳞翅目昆虫类。双翅目和鳞翅目昆虫序列进化上突然分化的原因尚不清楚，但可能是配体结合类型的改变或配体的完全丢失。
The cellular response to steroid hormones is mediated by nuclear receptors which act by regulating transcription. In Drosophila melanogaster, the receptor for the insect molting hormone, 20-hydroxyecdysone, is a heterodimer composed of the Ecdysone Receptor and Ultraspiracle (USP) proteins. The DNA binding domains of arthropod USPs and their vertebrate homologs, the retinoid X receptor (RXR) family, are highly conserved. The ligand binding domain sequences, however, divide into two distinct groups. One group consists of sequences from members of the holometabolous higher insect orders Diptera and Lepidoptera, the other of sequences from vertebrates, a crab and a tick. We here report the sequence of an RXR/USP from the hemimetabolous orthopteran, Locusta migratoria. The locust RXR/USP ligand binding domain clearly falls in the vertebrate-crab-tick rather than the dipteran-lepidopteran group. The reason for the evolutionarily abrupt divergence of the dipteran and lepidopteran sequences is unknown, but it could be a change in the type of ligand bound or the loss of ligand altogether.