Figure 1. Subcellular localization of Arhgap11a mRNA and protein to RGC basal processes and endfeet during cortical development.

(A) Cartoon of a radial glial progenitor (RGC, green) with mRNA transport along the basal process and local translation in endfeet. Question marks reflect goal of the present study: what is the role of mRNA subcellular localization and translation in RGCs and for positioning of excitatory neurons (orange), migratory interneurons (purple), and cajal-retzius neurons (blue)?

(B) qPCR analyses of Arhgap11a mRNA levels in E14.5 sorted embryonic cortical cells. (n=4 brains, 3 technical replicates)

(C,D) Quantification of ARHGAP11A Immunofluorescence in E11.5, E13.5 and E15.5 brains. (E-G) Immunofluorescence of ARHGAP11A (grey) and Hoechst (blue) in E11.5 (E), E13.5 (F) and E15.5 (G) brains.

(H) Immunofluorescence of ARHGAP11A (red) at E15.5, showing expression in NESTIN positive RGCs (green) with overlap (yellow signal) in basal process and endfeet at the pial surface (yellow arrows).

(I,J) In situ hybridization of Arhgap11a mRNA (purple signal), showing strong enrichment at the pia where RGC basal endfeet reside (red arrows) at E14.5 (I) and in GW11 human fetal brains (J).

(K,L) smFISH in situ hybridization depicting Arhgap11a mRNA (red) at the pia at E15.5 (K) and in EGFP+ RGC basal endfeet (brains electroporated one day earlier) (L). Right panels, magnified areas highlighted in left panels (K, L) and maximum intensity projections of a z-stack (L).

(M) smFISH and immunofluorescence targeting Arhgap11a mRNA (red) and protein (green), respectively highlights colocalization (arrows) in RGC basal endfeet.

VZ: ventricular zone, CP: cortical plate, IZ: intermediate zone, smFISH: single molecule fluorescent in situ hybridization. Scale bars: C-E, 20 μm; I, 20 μm; J, left panel: 5 μm, right panel: 1μm; M, 20 μm.