Figure 3.
Neurons Induced by Ngn2/Nurr1 Develop Spines and Project to the Appropriate Brain Regions
(A) Photomicrographs and quantification of spines on secondary dendrite segments of endogenous (top) and induced (bottom) neurons at 24 and 72 dpi of mScarlet-I/Ngn2/Nurr1; n = 4 animals.
(B) Patch-clamp recording of endogenous or induced neurons in acute slice preparations of the cortex at 72 dpi as shown in the laser-Dodt-contrast and fluorescence images of mScarlet-I+ cell, before (top) and after filling the recorded cell with Alexa 488 (bottom).
(C) Left: action potential in response to 100-ms current injection in 72 dpi iN shown in (B) (timescale expanded). Right: current-voltage responses recorded during 1-s current pulses from −300 to +400 pA are shown (of the same cell).
(D) Excitatory spontaneous synaptic currents recorded in voltage clamp at −70 mV in mScarlet-I+ iNs (top trace) are blocked by NBQX (2nd trace). Inhibitory spontaneous synaptic currents recorded at −30 mV (3rd trace from top) are blocked by bicuculline (bottom trace).
(E and F) Photomicrographs of mScarlet-I+ iN axons at 72 dpi in the ipsilateral (E) and contralateral (F) cortical hemisphere.
(G) Left: schematic drawing indicating the experimental schedule and positions of callosal neurons with a low-power overview photomicrograph depicting the Fluorogold injection site. Middle: retrogradely traced iNs at 72 dpi are mainly located in L2/3 and L5. Right: histograms illustrate the percentage of Fluorogold+ endogenous or induced neurons in L2/3 that are SATB2+/CTIP2− and in L5 that are SATB2+/CTIP2− or SATB2−/CTIP2+ neurons; n = 3 animals.
Data are shown as median ± IQR. One-way ANOVA. ∗∗p ≤ 0.01; ∗∗∗p ≤ 0.001; ∗∗∗∗p ≤ 0.0001. cc, corpus callosum; Crb, cerebellum; Ctx, cortex; ic, internal capsule; OB, olfactory bulb; SC: spinal cord; Str, striatum; Th, thalamus; VL, lateral ventricle. Scale bars: 100 μm (E, left; F, left; and G, overview); 50 μm (E, right and F, middle); 20 μm (B and G, close up); 10 μm (A and F, right).
See also Figure S5.