Drosophila Neural Stem Cells: A Primer For Understanding Mammalian Neural Development And Disease

Drosophila is an established model for over a century to study the genetic, epigenetic, and molecular aspects of various cellular processes. Conservation of gene regulatory mechanisms, signaling pathways, and homology of over 75% of fly genes with mammals have helped us understand diverse aspects of human biology. Drosophila neural stem cells (NSCs) or neuroblasts (NBs) were first identified in the nineteenth century; since then, they are being used as a model to understand the underlying mechanisms of the stem cell fate determination. The countless possibilities to manipulate the fly genome prove advantageous to address complicated questions of stem cell biology.Stem cell lifecycle is dynamically regulated and is far more intricate than the normal cells. Stem cells have the property to self-renew, differentiate, or undergo dormancy until they are required again. Moreover, NSCs generate diverse progeny to perform specialized functions and are capable to end their life either by apoptosis or exit the cell cycle after fulfilling the required purpose. How are these complicated and yet organized cellular processes to make a functional nervous system regulated? What are the cues involved in the process? Are they all intrinsic to NSCs or does the stem cell environment have a role to play as well? In this chapter, we have discussed and summarized the information available to address these questions. We have reviewed and compared various conserved aspects of fly NSC biology with mammalian NSC behaviors. It is interesting to learn that the stem cells do not function in isolation and the systemic signaling and cues from its micro and macro environments play distinct roles to regulate the NSC fate decisions. Thus, a better understanding of cell intrinsic and cell extrinsic signaling and how they communicate and function in sync with the environment is necessary for effective use of stem cells in translational research.