Susie Doyle

During development, neural stem cells (NSCs) divide asymmetrically, sequentially expressing a series of intrinsic factors to generate a diversity of neuron types. After cycling through temporal programs, NSCs terminally differentiate or die, bringing an end to developmental neurogenesis.

Most neurogenesis occurs during development, driven by the cell divisions of neural stem cells (NSCs). We use Drosophila to understand how neurogenesis terminates once development is complete, a process critical for neural circuit formation.

Correct positioning of stem cells within their niche is essential for tissue morphogenesis and homeostasis. Yet how stem cells acquire and maintain niche position remains largely unknown. Here, we show that a subset of brain neuroblasts (NBs) in Drosophila utilize PI3-kinase and DE-cadherin to build adhesive contact for NB niche positioning.

Stem cells enter and exit quiescence as part of normal developmental programs and to maintain tissue homeostasis during adulthood. We report that neural stem cells in Drosophila (neuroblasts) require the evolutionarily conserved Notch cell-cell signaling pathway to enter quiescence during development.

In Drosophila, there are 14 neurosecretory neurons located in the pars intercerebralis (the fly hypothalamus) that synthesize and secrete 3 of the 8 Drosophila insulin-like peptides (Dilps). Dilps bind to and activate the single Insulin-like tyrosine kinase receptor, which leads to downstream activation of the evolutionarily conserved PI3-kinase growth signaling pathway.

We continue to make use of Drosophila as a genetic model to identify genes required for termination of neurogenesis. Through screening, using UAS-RNAi lines generated by the Transgeneic RNAi Project (TRiP), we have identified 14 genes.