Proneural role of asense in the Drosophila neuroepithelial to neuroblast transition

Resumen del póster presentado al European Developmental Biology Congress (EDBC), celebrado en Alicante del 23 al 26 de octubre de 2019.The regulation of the switch from proliferating (symmetrically dividing) to neurogenic (asymmetrically dividing) neural progenitors is crucial in the brain development to achieve the correct size and the correct cell types for a proper function. Vertebrate neural stem cells have similar properties than Drosophila Neuroblasts (NB). During Drosophila Optic Lobe (OL) neurogenesis, neuroepithelial (NE) cells differentiate into NB. This transition occurs synchronously in a row of cells performing a proneural wave. The synchrony and the order of this process make the OL a perfect model to better understand the regulation of this key transition. It has been described that the NE-NB transition is triggered by the expression of lethal of scute (l'sc), a proneural factor of the achaete-scute gene complex. This expression depends on the integration of EGFR, Notch and JAK/STAT signaling pathways. Interestingly, we have observed that asense (ase), another achaete-scute complex gene, is transiently upregulated in the transition from NE to NB. Given the known proneural function of the mammalian ase orthologue Ascl1/Mash1 we have analyze the possible functions of Ase in the regulation of the OL proneural wave. We describe by first time a proneural role of Ase in the CNS and examine the consequences of its transitory expression. We find that Ase is required for a correct NE-NB transition and, moreover, is sufficient to induce this transition in a L'sc non-mediated manner.This work has been supported by grants from the AEI/FEDER-EUPeer reviewe