The anti-neural role of BMP signaling is a consequence of its ancestral function in dorsoventral patterning

by Paul Knabl, June F. Ordoñez, Juan Daniel Montenegro Cabrera, Daniel Abed-Navandi, Roland Halbauer, Oliver Link, Tim Wollesen, Grigory Genikhovich In Bilateria with centralized nervous systems (e.g., in vertebrates or arthropods), the minimum of the BMP signaling activity gradient defines the position of the central nervous system. BMP-dependent patterning of the secondary body axis is ancestral for Bilateria and possibly also for the bilaterian sister clade Cnidaria. However, the variety of levels of centralization of the nervous systems in Bilateria—from diffuse to fully centralized—as well as the lack of centralization of the nervous system in Cnidaria, suggest that BMP signaling cannot be perceived as a universally “anti-neural” signal. Here we use transgenic reporter lines in the anthozoan cnidarian Nematostella to show that BMP signaling is active in distinct neuronal populations. Moreover, attenuation of BMP signaling followed by RNA-Seq shows that BMP signaling is a positive