During development, neural tissues, including the brain, become progressively more sophisticated and complex: neuron numbers increase as well as the molecular diversity of neuron subtypes produced. Yet, at the same time, the capacity for generating new, molecularly distinct neuron types becomes diminished, because as development proceeds, neurogenesis rates and identity change and numbers of NSCs decline. We are investigating how neurogenesis becomes progressively restricted during development.
To identify genes required for termination of neurogenesis, we are conducting large-scale RNAi screens in Drosophila. We have identified a number of UAS-RNAi lines that when expressed in NSCs, termed neuroblasts, allows for their continued proliferation in adult brains. These lines target a number of highly conserved transcriptional regulators and genes involved in cell signaling. Pictured here is a young adult Drosophila brain expressing an RNAi line of interest in neuroblasts using worGAL4. Several Dpn-positive neuroblasts and intermediate neural progenitors (INPs) are present, some of which maintain proliferation based on expression of the S-phase activity reporter, pcna:GFP.