Fig. 5: Conditional deletion of Trio in GABAergic INs induces morphological deficits in developing INs and impairs the dynamics of tangential migration.
A–I The morphology of GABAergic INs at e13.5 is impaired in TriocKO brains. Examples of GFP+ fate-mapped cortical INs imaged at the migratory front in 50 µm-thick coronal brain sections from TrioWT (A) and TriocKO (B) littermates at e13.5, with their respective 3D reconstruction (A’, B’). Histograms showing measurements for (C) cell body area, (D) number, (E) complexity and (F) length of leading neurites, as well as (G) number, (H) complexity and (I) length of trailing neurites. (n = 64 cells from 3 TrioWT brains and 94 cells from 4 TriocKO brains). J–S GABAergic IN migration and branching dynamics are impaired in TriocKO embryonic brains. (J) Schematic of the experimental design for live-imaging of e13.5 organotypic brain slices after 2 h in culture. Time-lapse sequences showing the migration of GFP+ INs in organotypic brain slices from TrioWT (K-K”) and TriocKO (L-L”) mouse embryos. (M–S) Histograms showing (M) the migration speed, (N) the total distance, (O) the net displacement, (P) the directionality, as well as (Q) nucleokinesis frequency, (R) duration and (S) amplitude of TrioWT and TriocKO GFP+ INs (n = 53 cells from 3 TrioWT brains and 46 cells from 3 TriocKO brains). T Schematic of the experimental design for the live-imaging of MGE explant cultures. Time-lapse sequences showing the migration and branching of (U) GFP+ TrioWT and (V) TriocKO INs in MGE explant cultures. W Histograms showing the frequency of growth cone splitting and (X) the lifetime of newly formed branches during migration. Y–AA Histograms showing the branch order classification during migration (n = 57 GFP + MGE-INs from 3 TrioWT brains and 50 GFP + MGE-INs from 3 TriocKO brains). See also Supplementary Fig. 2 for data on migration dynamics and nucleokinesis in explants. *P < 0.05, **P < 0.01 and ****P < 0.0001, by Student’s t test. Scale bars: 20 µm (A), 100 µm (L”) and 50 µm (V).
