Meeting Abstract
Sponges, an animal without nerves, have an intriguing number of neural developmental and structural genes. Moreover, some demosponges can sense changes in flow and respond with a choreographed inflation-contraction behavior that flushes obstructions from the canals. Sensory abilities and initiation of this behavior can be traced to primary cilia in the osculum, the excurrent vent of the sponge. Thus while the genetic mechanisms remain unknown the osculum may function as a sensory and coordinating hub. In the calcareous sponge Sycon ciliatum the neurodevelopmental genes SoxB and Musashi are upregulated at the top of the sponge, which is both the growing region and location of the osculum. However, a sensory system in this sponge has not yet been documented. To investigate whether such genes may be involved in the development of the osculum, we performed an RNAseq experiment in the demosponge Spongilla lacustris using sponges that were flash frozen during the stages preceding and following osculum development. In addition, we performed a second RNAseq experiment comparing gene expression in the osculum vs. body tissue of Aphrocallistes vastus, a deep sea glass sponge that possesses oscular cilia and exhibits a behavioral response to changes in ambient flow. Aphrocallistes also has electrical signaling and we asked whether genes involved in neural signaling in other animals are more highly expressed in that sponge’s osculum. In probing the genetic mechanisms of the osculum we aim to investigate the shared biology of sensory structures across animals while characterizing the foundations of a unique, sponge-specific sensory system.
