Evolutionary and developmental origin of the nervous system

Little is known about the genetic and developmental mechanisms that led to the evolution of the nervous system in the ancestors of eumetazoans. We plan to address the issue by studying a basal metazoan - the cnidarian Nematostella vectensis. The cnidarians are a sister group to bilaterians and possess a surprising complexity of genetic network, yet a relatively simple overall morphology including a diffuse nervous system. By studying the neural progenitors, we aim to address the problem from a developmental point of view. We propose to employ the state-of-the-art technology including gene knockdown, transgenics and live imaging in order to gain insight into the molecular characteristics of neural progenitors of Nematostella to understand how neuronal precursors are determined and born and how the different populations of neural progenitors relate to neuronal diversity present in Nematostella. We will focus our molecular analysis on elucidating the function of the neural progenitor marker SoxB2, in order to determine the role in the genetic hierarchy of the formation of the first nervous systems. The host lab has just created a transgenic line driven by the SoxB2 promoter and identified several neuronal enhancers. This offers the unique possibility to study neurogenesis in vivo. Last, we will perform a comparative analysis of Nematostella neural progenitor make up with other cnidarians and bilaterians. This will elucidate the common and distinct features of cnidarian and bilateral nervous systems, which in turn will enable us to reconstruct the common ancestor.