Klompen Anna M L, Sanders Steven M, Cartwright Paulyn
Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA.
Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA.
Toxicon X. 2022 Mar 4;14:100113. doi: 10.1016/j.toxcx.2022.100113. eCollection 2022 Jun.
Cnidarians (jellyfish, hydroids, sea anemones, and corals) possess a unique method for venom production, maintenance, and deployment through a decentralized system composed of different types of venom-filled stinging structures called nematocysts. In many species, nematocyst types are distributed heterogeneously across functionally distinct tissues. This has led to a prediction that different nematocyst types contain specific venom components. The colonial hydrozoan, is an ideal system to study the functional distribution of nematocyst types and their venoms, given that they display a division of labor through functionally distinct polyps within the colony. Here, we characterized the composition and distribution of nematocysts (cnidome) in the different polyp types and show that the feeding polyp (gastrozooid) has a distinct cnidome compared to the reproductive (gonozooid) and predatory polyp (dactylozooid). We generated a nematocyst-specific reporter line to track nematocyst development (nematogenesis) in , and were able to confirm that nematogenesis primarily occurs in the mid-region of the gastrozooid and throughout stolons (tubes of epithelia that connect the polyps in the colony). This reporter line enabled us to isolate a nematocyst-specific lineage of cells for transcriptome assembly, annotate venom-like genes (VLGs) and determine differential expression (DE) across polyp types. We show that a majority of VLGs are upregulated in gastrozooids, consistent with it being the primary site of active nematogenesis. However, despite gastrozooids producing more nematocysts, we found a number of VLGs significantly upregulated in dactylozooids, suggesting that these VLGs may be important for prey-capture. Our transgenic reporter line provides an opportunity to explore the complex interplay between venom composition, nematocyst diversity, and ecological partitioning in a colonial hydrozoan that displays a division of labor.
刺胞动物（水母、水螅虫、海葵和珊瑚）拥有一种独特的毒液产生、维持和释放方式，其通过一个分散的系统来实现，该系统由不同类型充满毒液的刺丝囊组成，刺丝囊是一种刺细胞结构。在许多物种中，刺丝囊类型在功能不同的组织中呈异质分布。这导致了一种预测，即不同类型的刺丝囊含有特定的毒液成分。群体水螅虫是研究刺丝囊类型及其毒液功能分布的理想系统，因为它们通过群体内功能不同的水螅体表现出分工。在这里，我们描述了不同水螅体类型中刺丝囊（刺胞囊）的组成和分布，并表明摄食水螅体（胃丝螅）与生殖水螅体（生殖体）和捕食水螅体（指状螅）相比具有独特的刺胞囊。我们生成了一个刺丝囊特异性报告系来追踪群体水螅虫中的刺丝囊发育（刺丝囊发生），并能够确认刺丝囊发生主要发生在胃丝螅的中部区域以及整个匍匐茎（连接群体中水螅体的上皮管）。这个报告系使我们能够分离出群体水螅虫中刺丝囊特异性的细胞谱系用于转录组组装，注释类毒液基因（VLGs）并确定不同水螅体类型之间的差异表达（DE）。我们表明大多数VLGs在胃丝螅中上调，这与它是活跃刺丝囊发生的主要部位一致。然而，尽管胃丝螅产生更多的刺丝囊，我们发现一些VLGs在指状螅中显著上调，这表明这些VLGs可能对捕获猎物很重要。我们的转基因群体水螅虫报告系为探索一种表现出分工的群体水螅虫中毒液成分、刺丝囊多样性和生态划分之间的复杂相互作用提供了一个机会。
