Multiple origins and modularity in the spatiotemporal emergence of cerebellar astrocyte heterogeneity
Fig 10
Schematic model for emergence of cerebellar astroglial lineages.
Cerebellar astrogliogenesis occurs from RG that either generate HomCs for each major astrocyte type—more frequent among vermian E14-P30 clones—or HetCs. HetCs, including double and triple clones, are proposed to originate from intermediate basal progenitors derived from RG. Double clones are similarly produced by either E12 or E14 RG and appear composed on average of 2 subclones with the same modularity. In these subclones, BG dominates over GLAs, likely as the result of the amplification of ventricular progenitors translocated into the PCL. Triple clones, more frequent among E12-P30 lineages, include the 3 major astrocyte types and appear composed by 3 subclones belonging to distinct typologies, depending on the presence of WMAs. Subclones can be formed by BG+GLA types, in which case they show modularity, and by BG+GLA+WMA types, in which case there is no apparent modularity but a very diverse cell type composition. BG, Bergmann glia; E, embryonic day; GL, granular layer; GLA, granular layer astrocyte; HetC, heterogeneous clone; HomC, homogeneous clone; RG, radial glia; PCL, Purkinje cell layer; PWM, prospective white matter; VZ, ventricular zone; WMA, white matter astrocyte.