Ascl1 confers neurogenic potential to late progenitors of the mouse spinal cord

ABEL CARCAGNO; DANIELA DI BELLA; LUCIA BARTOLOMEU; MARIA BELÉN PARDI; NICOLE SIEGEL; ANTONIA MARIN-BURGIN; GUILLERMO LANUZA

Buenos aires

Congreso; Latin American Society for Developmental Biology Meeting; 2019

Latin American Society for Developmental Biology

The generation of the precise neuronal types at the right time, location andnumber, is essential for building a functional nervous system. In the last 20 years,considerable progress has been made in understanding the genetic mechanisms that control neuron specification during embryonic development, and how positional coordinates determine neuronal identity. However, the temporalcontribution to neuronal diversity has been less explored. We have recentlyidentified a neurogenic event in the mouse spinal cord that takes place, duringadvanced embryonic stages, simultaneously with glial specification previouslyconsidered non-neurogenic. CerebroSpinal Fluid contacting Neurons (CSF cN) arewidely conserved in chordates, have a unique morphology and are generated fromlate ventral spinal cord progenitors. The genetic mechanisms that allow thedifferentiation of this class of neurons at gliogenic stages are unknown. Usingknock-out mice, genetic labeling and expression analysis we show that thetranscription factor Ascl1 is expressed in progenitors that give rise to CSF cN and that Ascl1 is necessary for CSF-cN development. Finally, fate mappingexperiments in the absence of Ascl1 demonstrated that it confers neurogenicpotential to late ventral progenitors, which would otherwise become ependymalcells. We conclude that Ascl1 directs the specification of CSF cN in the gliogenic neural tube controlling the precise neuronal and nonneuronal composition of the spinal central canal.