Department of Molecular, Cellular Biology and Biochemistry, BioMed Division, Brown University, 185 Meeting Street, Providence, RI, 02912, USA.
Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA.
Nat Commun. 2023 May 9;14(1):2402. doi: 10.1038/s41467-023-37947-2.
A fundamental goal in the organogenesis field is to understand how cells organize into tubular shapes. Toward this aim, we have established the hydro-vascular organ in the sea star Patiria miniata as a model for tubulogenesis. In this animal, bilateral tubes grow out from the tip of the developing gut, and precisely extend to specific sites in the larva. This growth involves cell migration coupled with mitosis in distinct zones. Cell proliferation requires FGF signaling, whereas the three-dimensional orientation of the organ depends on Wnt signaling. Specification and maintenance of tube cell fate requires Delta/Notch signaling. Moreover, we identify target genes of the FGF pathway that contribute to tube morphology, revealing molecular mechanisms for tube outgrowth. Finally, we report that FGF activates the Six1/2 transcription factor, which serves as an evolutionarily ancient regulator of branching morphogenesis. This study uncovers distinct mechanisms of tubulogenesis in vivo and we propose that cellular dynamics in the sea star hydro-vascular organ represents a key comparison for understanding the evolution of vertebrate organs.
器官发生领域的一个基本目标是了解细胞如何组织成管状形状。为此，我们建立了海星 Patiria miniata 的水脉器官作为管状发生的模型。在这种动物中，双侧管从发育中的肠道末端长出，并精确地延伸到幼虫的特定部位。这种生长涉及细胞迁移，伴随着特定区域的有丝分裂。细胞增殖需要 FGF 信号，而器官的三维取向取决于 Wnt 信号。管细胞命运的特异性和维持需要 Delta/Notch 信号。此外，我们鉴定了 FGF 通路的靶基因，这些基因有助于管形态的形成，揭示了管延伸的分子机制。最后，我们报告 FGF 激活了 Six1/2 转录因子，它是分支形态发生的古老调节因子。这项研究揭示了体内管状发生的不同机制，我们提出海星水脉器官的细胞动力学代表了理解脊椎动物器官进化的关键比较。
