Multiple origins and modularity in the spatiotemporal emergence of cerebellar astrocyte heterogeneity
Fig 1
In utero StarTrack electroporations and clone allocation in the cerebellum.
(A) Schematic representation of the experimental design. The hGFAP-StarTrack mixture was electroporated at E12 or E14, and clonal analysis was performed at P30. (B,C) StarTrack-labeled astrocytes are found in all cerebellar layers in P30 mice and comprise WMAs (white arrows), GLAs (white arrowheads), and BG (yellow arrowheads). In B’, 2 sister GLAs share the same combination of fluorescent proteins (asterisks), whereas the third GLA displays a different color combination, thus deriving from a different progenitor, even though it is very close to the other 2 GLAs. (D) Schematic representation of the relative M-L extension of each clone. E12-P30 clones (green) preferentially settle in the cerebellar hemispheres, whereas E14-P30 families (orange) are exclusively located in the vermis. Based on the cerebellar symmetry around the midline, all clones are projected on one-half cerebellum. The paravermis is defined as that region where lobule IX fades and lobule X is still present. (E) Diagrams are representative of clone distribution along the A-P axis. E12-P30 clones (green) are homogeneously distributed in all lobules of the hemispheres, whereas E14-P30 ones (orange) preferentially occupy the ventral vermis, including both anterior and posterior folia. Each dot corresponds to 1–2 clones. When clones are found in >1 lobule, they are repeatedly represented in each corresponding folium. Scale bars: 30 μm. A-P, antero-posterior; BG, Bergmann glia; CI and CII, CrusI and CrusII; Cp, copula pyramidis; D-V, dorso-ventral; E, embryonic day; GFP, green fluorescent protein; GLA, granular layer astrocyte; hGFAP, human glial fibrillary acidic protein; mCerulean, monomeric Cerulean; mCherry, monomeric Cherry; mKO, mKusabira Orange; M-L, medio-lateral; mT-Sapphire, monomeric T-Sapphire; P, postnatal day; PCL, Purkinje cell layer; Pm, paramedian; S, Simplex; WM, white matter; WMA, white matter astrocyte; YFP, yellow fluorescent protein.