Asymmetric Cell Division inDrosophilaNeuroblasts

Abstract

Neuronal diversity provides the basis for brain complexity. Asymmetric division of neural stem cells is a fundamental strategy for generating such diversity. Drosophila neural stem cells called neuroblasts emerge as a key model for in‐depth understanding of asymmetric division. Asymmetric division of neuroblasts is regulated by a group of highly conserved intrinsic factors through three critical steps: establishment of cortical polarity, mitotic spindle orientation and asymmetric localisation/segregation of cell fate determinants. With each round of asymmetric division, a neuroblast generates a new neuroblast to self‐renew and a ganglion mother cell (GMC) that divides terminally giving rise to two neurons. In addition, neuroblasts acquire different temporal identities that contribute to the differential neurons subtypes generated. Key Concepts Asymmetric cell division is regulated by intrinsic machinery. Par complex establishes cortical polarity of neuroblasts. Pins–Gαi complex regulates spindle orientation. Basal cell fate determinants promote neuronal differentiation. Cell cycle regulators regulate asymmetric division of neuroblasts. Positioning of cleavage furrow is regulated by two temporally independent pathways. Temporal regulation of neuroblasts generates neuronal diversity.

Parafibromin governs cell polarity and centrosome assembly in Drosophila neural stem cells

“…The dysregulation of a few cell cycle regulators, such as Aurora-A kinase (AurA), Polo kinase (Polo), and Serine/Threonine protein phosphatase 2A (PP2A) results in disruption to NSC asymmetry and microtubule functions, leading to NSC overgrowth and brain tumor formation [ 27 , 29 , 35 , 37 – 43 ]. Moreover, ADP ribosylation factor like-2 (Arl2), a major regulator of microtubule growth, localizes Mini spindles (Msps)/XMAP215/ch-TOG and Transforming acidic coiled-coil containing (D-TACC) to the centrosomes to regulate microtubule growth and the polarization of NSCs [ 44 ].…”