While pair-rule patterning has been observed in most insects examined, the orthologs of Drosophila pair-rule genes have shown divergent roles in insect segmentation. In the beetle Tribolium castaneum, while odd-skipped (Tc-odd) was expressed as a series of pair-rule stripes, RNAi-mediated knockdown of Tc-odd (Tc-odd^RNAi) resulted in severely truncated, almost asegmental phenotypes rather than the classical pair-rule phenotypes observed in germbands and larval cuticles. However, considering that most segments arise later in germband stages of Tribolium development, the roles of Tc-odd in segmentation of growing germbands could not be analyzed properly in the truncated Tc-odd^RNAi germbands. Here, we investigated the segmentation function of Tc-odd in germband stages of Tribolium development by analyzing Tc-odd^RNAi embryos that resumed germband extension. In the larval cuticles of Tc-odd^RNAi embryos, normal mandibular and maxillary and loss of the labial segments were consistent in the head, whereas a broad range of segmentation defects including loss or fusion of thoracic and/or abdominal segments was observed in the trunk. Interestingly, a group of Tc-odd^RNAi germbands showed pair-rule-like defects in the segmental stripes of the segment-polarity genes, engrailed, hedgehog, or wingless, in the abdominal regions. While the pair-rule genes even-skipped, runt, odd, and paired were misregulated in the growing Tc-odd^RNAi germbands, paired expression required for odd-numbered segment formation was largely abolished, which might cause the pair-rule-like defects. Taken together, these findings suggest that Tc-odd can function as a pair-rule gene in the germband stages of Tribolium development.

虽然在大多数被检查的昆虫中都观察到了成对规则模式，但果蝇成对规则基因的直系同源物在昆虫分割中显示出不同的作用。在甲虫Tribolium castaneum中，虽然将奇跳（Tc-odd）表示为一系列成对规则的条带，但RNAi介导的Tc-odd（Tc-odd ^RNAi）的敲低导致了严重的截短，几乎是分段的表型，而不是在种带和幼虫表皮中观察到的经典成对表型。但是，考虑到大部分片段是在Tribolium开发的种带阶段后期出现的，因此Tc-odd的作用在截短的Tc奇数^RNAi基因带中无法正确分析生长基因带的分割。在这里，我们通过分析可恢复种带延伸的Tc奇数^RNAi胚胎，研究了Tribolium发育的种带阶段中Tc-odd的分割功能。在Tc奇数^RNAi胚胎的幼虫表皮中，正常的下颌和上颌以及唇段的损失在头部是一致的，而在躯干中观察到了广泛的分割缺陷，包括胸段和/或腹节的丢失或融合。 。有趣的是，一组Tc奇数^RNAi生殖带在腹部区域的节段极性基因的节段条纹中显示成对规则状的缺陷，即卷入，刺猬或无翅。虽然成对规则基因偶数跳过，欠幅脉冲，奇数，并且成对的在生长的被误调节的Tc-奇数^的RNAi germbands，成对为奇数段形成所需表达在很大程度上消除，这可能会导致该对规则状缺陷。综上所述，这些发现表明，Tc-odd可以在Tribolium发育的生殖带阶段起成对规则基因的作用。