Regulating neural proliferation in the Drosophila CNS.
Neural stem and progenitor cells generate the central nervous system (CNS) in organisms as diverse as insects and mammals. In Drosophila, multipotent asymmetrically dividing progenitors called neuroblasts produce neurons and glia throughout the developing CNS. Nevertheless, the time-windows of mitotic activity, the division modes, the termination mechanisms and the lineage sizes of individual neuroblasts all vary considerably from region-to-region. Recent studies shed light on some of the mechanisms underlying this neuroblast diversity and, in particular, how proliferation is boosted in two brain regions. In the central brain, some specialised neuroblasts generate intermediate neural progenitors that can each divide multiple times, thus increasing overall lineage size. In the optic lobe, an alternative expansion strategy involves symmetrically dividing neuroepithelial cells generating large numbers of asymmetrically dividing neuroblasts. Evidence is also emerging for a cell-intrinsic timer that alters the properties of each neuroblast with increasing developmental age. The core mechanism corresponds to a series of transcription factors that coordinates temporal changes in neuronal/glial identity with transitions in neuroblast cell-cycle speed, entry into quiescence and, ultimately, with termination.
Sousa-Nunes
Rita
R
Medical Research Council, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW71AA, UK.
Cheng
Louise Y
LY
Gould
Alex P
AP
D000818:Animals; D002455:Cell Division / Q000502:physiology; D049109:Cell Proliferation; D002490:Central Nervous System / Q000166:cytology* / Q000502:physiology; D004330:Drosophila / Q000166:cytology* / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*