Regulation of Neurogenesis in the Planarian Schmidtea mediterranea Alexander Karge The planarian flatworm Schmidtea mediterranea is capable of recovery from nearly any injury, including regenerating an entire brain after decapitation, made possible by a pool of pluripotent stem cells which maintain all of the worm's tissues into adulthood. However, the signals that control the production of new neurons in these animals are largely unknown. This work investigates several different regulatory

more »

... cts of neurogenesis. First, I present a RNAi screen of intracellular and cell surface signaling molecules searching for negative regulators of neurogenesis which identified tec-1, encoding a planarian Tec family kinase. I determined that tec-1 suppresses cell number in many different neuronal cell types by promoting neuronal cell death, describing a novel process for controlling neuron abundance in this organism. Then, I present a RNAi screen which prospectively identified transcription factors required for the production of specific neuronal gene expression. In addition to uncovering previously unknown neurogenic transcription factors, this screen demonstrated novel functions for transcription factors previously known to be involved in neurogenesis. These data add deeper understanding of how planarians regulate the regeneration of a functioning central nervous system.