Development of the aboral domain in Nematostella requires beta-catenin and the opposing activities of Six3/6 and Frizzled5/8

作者：Leclere Lucas; Bause Markus; Sinigaglia Chiara; Steger Julia; Rentzsch Fabian

来源：Development, 2016, 143(10): 1766-1777.

DOI：10.1242/dev.120931

• Anterior posterior axis
• Apical organ
• Axis formation
• Cnidaria
• Wnt signaling

The development of the oral pole in cnidarians and the posterior pole in bilaterians is regulated by canonical Wnt signaling, whereas a set of transcription factors, including Six3/6 and FoxQ2, controls aboral development in cnidarians and anterior identity in bilaterians. However, it is poorly understood how these two patterning systems are initially set up in order to generate correct patterning along the primary body axis. Investigating the early steps of aboral pole formation in the sea anemone Nematostella vectensis, we found that, at blastula stage, oral genes are expressed before aboral genes and that Nv beta-catenin regulates both oral and aboral development. In the oral hemisphere, Nv beta-catenin specifies all subdomains except the oral-most, NvSnailA-expressing domain, which is expanded upon Nv beta-catenin knockdown. In addition, Nv beta-catenin establishes the aboral patterning system by promoting the expression of NvSix3/6 at the aboral pole and suppressing the Wnt receptor NvFrizzled5/8 at the oral pole. NvFrizzled5/8 expression thereby gets restricted to the aboral domain. At gastrula stage, NvSix3/6 and NvFrizzled5/8 are both expressed in the aboral domain, but they have opposing activities, with NvSix3/6 maintaining and NvFrizzled5/8 restricting the size of the aboral domain. At planula stage, NvFrizzled5/8 is required for patterning within the aboral domain and for regulating the size of the apical organ by modulation of a previously characterized FGF feedback loop. Our findings suggest conserved roles for Six3/6 and Frizzled5/8 in aboral/anterior development and reveal key functions for Nv beta-catenin in the patterning of the entire oral-aboral axis of Nematostella.

• 出版日期2016-5-15