Fig. 3

Absence of retinal terminals in dLGN of math5 ^−/−. a-c Coronal sections of dLGN showing the labeling pattern of the retinal terminal marker vesicular glutamate transporter 2 (VGluT2) in WT (a), math5 ^−/− (b), and math5 ^−/− seven days after binocular enucleation (c). At P14, there is strong expression of VGluT2 in WT and almost a complete absence in math5 ^−/− (b), comparable to levels observed after binocular enucleation (c). Insets show high power images corresponding to the area denoted by the asterisk. Dashed lines in (a), (b), and (c) outline the border of dLGN, and scale bar for (a, b, c) = 200 μm, and 110 μm for the insets. d-e) Electron microscopy images revealing the ultrastructure of the dLGN in WT (d) and math5 ^−/− mice (e). d Retinal terminals in WT mice (blue) include distinctive pale mitochondria (white asterisks). These terminals primarily synapse (arrows) on non-GABAergic dendrites (green), which often extend small protrusions into the presynaptic retinal terminals. E) In math5 ^−/− mice, the dLGN contains no terminals with pale mitochondria. Instead, large profiles (blue) with dark mitochondria (black asterisks) form synaptic arrangements that are similar to retinal terminals, including contacts on non-GABAergic dendritic protrusions (green). GABAergic profiles (pink) are identified by a high density of overlying gold particles. Scale bar = 1 μm and applies to both panels