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Development. 2017 Oct 1;144(19):3454-3464. doi: 10.1242/dev.149500. Epub 2017 Aug 29.

Imp and Syp RNA-binding proteins govern decommissioning of Drosophila neural stem cells.

Author information

1
Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA.
2
Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
3
MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom.
4
Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA leet@janelia.hhmi.org.

Abstract

The termination of the proliferation of Drosophila neural stem cells, also known as neuroblasts (NBs), requires a 'decommissioning' phase that is controlled in a lineage-specific manner. Most NBs, with the exception of those of the mushroom body (MB), are decommissioned by the ecdysone receptor and mediator complex, causing them to shrink during metamorphosis, followed by nuclear accumulation of Prospero and cell cycle exit. Here, we demonstrate that the levels of Imp and Syp RNA-binding proteins regulate NB decommissioning. Descending Imp and ascending Syp expression have been shown to regulate neuronal temporal fate. We show that Imp levels decline slower in the MB than in other central brain NBs. MB NBs continue to express Imp into pupation, and the presence of Imp prevents decommissioning partly by inhibiting the mediator complex. Late-larval induction of transgenic Imp prevents many non-MB NBs from decommissioning in early pupae. Moreover, the presence of abundant Syp in aged NBs permits Prospero accumulation that, in turn, promotes cell cycle exit. Together, our results reveal that progeny temporal fate and progenitor decommissioning are co-regulated in protracted neuronal lineages.

KEYWORDS:

Cell cycle exit; Mediator complex; Mushroom body; Neuroblast; RNA-binding protein

PMID:
28851709
PMCID:
PMC5665480
DOI:
10.1242/dev.149500
[Indexed for MEDLINE]
Free PMC Article

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