Laboratory of Morphogenesis Evolution, Koltzov Institute of Developmental Biology RAS, Vavilova 26, Moscow, 119334, Russia.
Department of Embryology, Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory 1/12, Moscow, 119234, Russia.
Sci Rep. 2023 Jun 9;13(1):9382. doi: 10.1038/s41598-023-35979-8.
Brachyury, a member of T-box gene family, is widely known for its major role in mesoderm specification in bilaterians. It is also present in non-bilaterian metazoans, such as cnidarians, where it acts as a component of an axial patterning system. In this study, we present a phylogenetic analysis of Brachyury genes within phylum Cnidaria, investigate differential expression and address a functional framework of Brachyury paralogs in hydrozoan Dynamena pumila. Our analysis indicates two duplication events of Brachyury within the cnidarian lineage. The first duplication likely appeared in the medusozoan ancestor, resulting in two copies in medusozoans, while the second duplication arose in the hydrozoan ancestor, resulting in three copies in hydrozoans. Brachyury1 and 2 display a conservative expression pattern marking the oral pole of the body axis in D. pumila. On the contrary, Brachyury3 expression was detected in scattered presumably nerve cells of the D. pumila larva. Pharmacological modulations indicated that Brachyury3 is not under regulation of cWnt signaling in contrast to the other two Brachyury genes. Divergence in expression patterns and regulation suggest neofunctionalization of Brachyury3 in hydrozoans.
Brachyury 是 T 盒基因家族的成员，因其在两侧对称动物中中胚层特化的主要作用而广为人知。它也存在于非两侧对称的后生动物中，如刺胞动物，在那里它作为轴向模式系统的一个组成部分。在这项研究中，我们对门刺胞动物纲中的 Brachyury 基因进行了系统发育分析，研究了差异表达，并提出了水螅纲 Dynamena pumila 中 Brachyury 旁系同源物的功能框架。我们的分析表明，Brachyury 在刺胞动物谱系中发生了两次复制事件。第一次复制可能发生在水母祖先中，导致水母中有两个拷贝，而第二次复制发生在水螅祖先中，导致水螅中有三个拷贝。Brachyury1 和 2 在 D. pumila 中表现出保守的表达模式，标记身体轴的口极。相反，Brachyury3 的表达在 D. pumila 幼虫的分散的推测神经细胞中被检测到。药理学调节表明，Brachyury3 不受 cWnt 信号的调节，与其他两个 Brachyury 基因不同。表达模式和调节的差异表明 Brachyury3 在水螅纲中的新功能化。
