Background Understanding the drivers of morphological diversity is a persistent challenge in evolutionary biology. Here, we investigate functional diversification of secretory cells in the sea anemone Nematostella vectensis to understand the mechanisms promoting cellular specialization across animals. Results We demonstrate regionalized expression of gland cell subtypes in the internal ectoderm of N. vectensis and show that adult gland cell identity is acquired very early in development. A phylogenetic survey of trypsins across animals suggests that this gene family has undergone numerous expansions. We reveal unexpected diversity in trypsin protein structure and show that trypsin diversity arose through independent acquisitions of non-trypsin domains. Finally, we show that trypsin diversification in N. vectensis was effected through a combination of tandem duplication, exon shuffling, and retrotransposition. Conclusions Together, these results reveal the numerous evolutionary mechanisms that drove trypsin duplication and divergence during the morphological specialization of cell types and suggest that the secretory cell phenotype is highly adaptable as a vehicle for novel secretory products.

中文翻译：

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对色蛋白组的基因组分析揭示了腺细胞进化的分子机制。

背景 了解形态多样性的驱动因素是进化生物学中的一项持久挑战。在这里，我们研究了海葵 Nematostella vectensis 分泌细胞的功能多样化，以了解促进动物细胞特化的机制。结果 我们证明了在 N. vectensis 的内部外胚层中腺体细胞亚型的区域化表达，并表明成人腺体细胞身份在发育的早期就获得了。一项跨动物胰蛋白酶的系统发育调查表明，该基因家族经历了多次扩展。我们揭示了胰蛋白酶蛋白质结构的意外多样性，并表明胰蛋白酶多样性是通过独立获得非胰蛋白酶结构域而产生的。最后，我们表明 N 中的胰蛋白酶多样化。vectensis 是通过串联重复、外显子改组和逆转录转座的组合来实现的。结论 总之，这些结果揭示了在细胞类型的形态特化过程中驱动胰蛋白酶复制和分化的众多进化机制，并表明分泌细胞表型作为新型分泌产物的载体具有高度适应性。