The transcription factors spineless (ss) and tiptop/teashirt (tio/tsh) have been shown to be selectors of distal appendage identity in an insect, but it is unknown how they regulate one another. Here, we examined the regulatory relationships between these two determinants in the milkweed bug Oncopeltus faciatus, using maternal RNA interference (RNAi). We show that Ofas‐ss RNAi embryos bear distally transformed antennal buds with heterogeneous Ofas‐tio/tsh expression domains comparable to wild type legs. In the reciprocal experiment, Ofas‐tio/tsh RNAi embryos bear distally transformed walking limb buds with ectopic expression of Ofas‐ss in the distal leg primordia. These data suggest that Ofas‐ss is required for the maintenance of Ofas‐tio/tsh expression in the distal antenna, whereas Ofas‐tio/tsh represses Ofas‐ss in the leg primordia. To assess whether expression boundaries of tio/tsh are associated with the trunk region more generally, we surveyed the expression of one myriapod and two chelicerate tio/tsh homologs. Our expression survey suggests that tio/tsh could play a role in specifying distal appendage identity across Arthropoda, but Hox regulation of tio/tsh homologs has been evolutionarily labile.

中文翻译：

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选择基因功能的演变：节肢动物中顶端/茶衫的表达动力学和调控相互作用。

转录因子无脊椎（ss）和顶端/茶衫（tio / tsh）已被证明是昆虫中远端附件身份的选择者，但未知它们如何相互调节。在这里，我们使用母体RNA干扰（RNAi）检查了乳草臭虫Oncopeltus faciatus中这两个决定因素之间的调节关系。我们表明，OFAS - SS RNA干扰胚胎熊远端转化触角芽异构OFAS -蒂奥/ TSH与野生型腿表达域。在对等实验中，Ofas - tio / tshRNAi胚胎带有远端转化的行走肢芽，在远端腿原基中异位表达Ofas-ss。这些数据表明，OFAS-SS需要维护的OFAS -蒂奥/ TSH在远端天线表达，而OFAS -蒂奥/ TSH压制OFAS - SS的腿原基。为了评估tio / tsh的表达边界是否更普遍地与躯干区域相关，我们调查了一个无足动物和两个螯合物tio / tsh同源物的表达。我们的表情调查显示，tio / tsh可以在节肢动物中确定远端附件身份方面发挥作用，但是tio / tsh同源物的Hox调节在进化上不稳定。