Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas.
Thomas E. Starzl Transplantation Institute and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
J Exp Zool B Mol Dev Evol. 2020 Jul;334(5):311-317. doi: 10.1002/jez.b.22980. Epub 2020 Jul 8.
Hydractiniid hydrozoan colonies are comprised of individual polyps connected by tube-like stolons or a sheet-like mat. Mat and stolons function to integrate the colony through continuous epithelia and shared gastrovascular cavity. Although mechanisms of hydrozoan polyp development have been well studied, little is known about the signaling processes governing the patterning of colonies. Here we investigate the Wnt receptor family Frizzled. Phylogenetic analysis reveals that hydrozoans possess four Frizzled orthologs. We find that one of these genes, Frizzled3, shows a spatially restricted expression pattern in colony-specific tissue in two hydractiniid hydrozoans, Hydractinia symbiolongicarpus and Podocoryna carnea, in a manner that corresponds to their distinct colony forms (stolonal mat in Hydractinia and free stolons in Podocoryna). Interestingly, Frizzled3 was lost in the genome of Hydra, which is a solitary polyp and thus lacks colony-specific tissue. Current evidence suggests that the Wnt signaling pathway plays a key role in the evolution of colony diversity and colony loss in Hydrozoa.
水螅水母群体由通过管状匍匐茎或片状垫连接的单个息肉组成。垫和匍匐茎通过连续的上皮和共享的胃腔血管来整合群体。尽管水螅水母息肉发育的机制已经得到了很好的研究，但对于控制群体模式形成的信号过程知之甚少。在这里，我们研究了 Wnt 受体家族 Frizzled。系统发育分析表明，水螅水母拥有四个 Frizzled 直系同源物。我们发现，这些基因中的一个，Frizzled3，在两种水螅水母 Hydractinia symbiolongicarpus 和 Podocoryna carnea 的特定于群体的组织中表现出空间限制的表达模式，其方式与它们独特的群体形式相对应（Hydractinia 中的匍匐茎垫和 Podocoryna 中的游离匍匐茎）。有趣的是，Frizzled3 在 Hydra 的基因组中丢失了，而 Hydra 是一个独居息肉，因此缺乏特定于群体的组织。目前的证据表明，Wnt 信号通路在水螅水母群体多样性和群体丧失的进化中起着关键作用。
