Active Notch Signaling is Required for Arm Regeneration ina Brittle Star

Cell signaling pathways play key roles to coordinate cellular events in development. Notch signaling pathway is highly conserved across all multicellular animals and is known to co- ordinate a multitude of diverse cellular events, including proliferation, differentiation, fate specification, and cell death. Specific functions of the pathway are however highly context- dependent and are not well characterized in post-traumatic regeneration. Here, we use a small-molecule inhibitor of the pathway (DAPT) to demonstrate that Notch signaling is required for proper arm regeneration in the brittle star Ophioderma brevispina, a highly re- generative member of the phylum Echinodermata. We also employ a transcriptome-wide gene expression analysis (RNA-seq) to characterize the downstream genes controlled by the Notch pathway in the brittle star regeneration.