Recent research has shown that Toll genes, and in particular a newly defined class of Toll genes, the so-called Long Toll Genes (Loto genes), are crucial factors in embryogenesis. In arthropods, they are involved in axis formation via a process called convergent extension (CE). A hallmark of Loto genes is their relatively (compared to other Toll genes) high number of leucine-rich repeat elements (LRRs) coupled with the fact that they are expressed in transverse stripes in all segments, or a subset of segments, patterns that are reminiscent of classical segmentation genes such as the pair-rule genes. Onychophorans represent a close outgroup to the arthropods; however, their embryonic development differs substantially. It is unclear if convergent extension contributes to onychophoran germ band formation and, if so, whether Loto genes are involved in governing this process. This study identifies a single onychophoran Toll gene from a sequenced embryonic transcriptome in two onychophoran species. The identified gene shows sequence and expression pattern characteristics of Loto genes. However, its expression pattern also comprises some general differences to arthropod Loto genes that are involved in CE.

中文翻译：

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Long Toll（Loto）基因在甲虫Euperipatoides kanangrensis和Cephalofovea clandestina中的胚胎表达。

最近的研究表明，Toll基因，特别是新近定义的一类Toll基因，即所谓的Long Toll基因（Loto基因），是胚胎发生的关键因素。在节肢动物中，它们通过称为会聚扩展（CE）的过程参与轴的形成。Loto基因的标志是相对大量的富含亮氨酸的重复元件（LRR）（与其他Toll基因相比），以及它们在所有节段或节段的子集中以横条纹表达的事实，让人联想到经典的分割基因，例如成对规则基因。甲虫是节肢动物的近亲。但是，它们的胚胎发育有很大的不同。目前尚不清楚会聚延伸是否有助于甲虫卵菌条带的形成，如果是的话，Loto基因是否参与调控这一过程。这项研究从两个甲虫卵的测序的胚胎转录组中鉴定出一个甲虫卵的Toll基因。鉴定出的基因显示了Loto基因的序列和表达模式特征。但是，它的表达方式也与节肢动物Loto基因所涉及的CE有一些一般性差异。