Ependymal cells are multiciliated cells located in the wall of the lateral 
ventricles of the adult mammalian brain and are key components of the 
subependymal zone niche, where adult neural stem cells reside. Through the 
movement of their motile cilia, ependymal cells control the cerebrospinal fluid 
flow within the ventricular system from which they receive secreted molecules 
and morphogens controlling self-renewal and differentiation decisions of adult 
neural stem cells. Multiciliated ependymal cells become fully differentiated at 
postnatal stages however they are specified during mid to late embryogenesis 
from a population of radial glial cells. Here we discuss recent findings 
suggesting that 2 novel molecules, Mcidas and GemC1/Lynkeas are key players on 
radial glial specification to ependymal cells. Both proteins were initially 
described as cell cycle regulators revealing sequence similarity to Geminin. 
They are expressed in radial glial cells committed to the ependymal cell lineage 
during embryogenesis, while overexpression and knock down experiments showed 
that are sufficient and necessary for ependymal cell generation. We propose that 
Mcidas and GemC1/Lynkeas are key components of the molecular cascade that 
promotes radial glial cells fate commitment toward multiciliated ependymal cell 
lineage operating upstream of c-Myb and FoxJ1.