Figure 6

Coexistence of neurons and astrocytes from distinct origins.

IUE was performed on Nkx2.1^Cre; Ai9 animals. A, B, In the neocortex, IUE-labeled GFP⁺ neurons (green) are distributed in upper layers where tdTomato⁺ cells from Nkx2.1⁺ PD (red) (A) are distributed only sparsely. There is no co-localization of green and red signals (B), indicating distinct origins of the red and green cells. Although the distribution of GFP⁺ cells and tdTomato⁺ cells are different, both cells coexisted in some regions such as the neocortex (B) and striatum (C). In regions such as the piriform cortex (D) and striatum (E), we occasionally encountered GFP⁺ astrocytes in association with tdTomato⁺ neurons (leftmost panels of D and E). F, Astrocytes enwrapping neurons. Large white arrows point to hole-like structures occupied tdTomato⁺ neuron. There are also hole-like structured not occupied by tdTomato-labeled neurons (small arrows). F1, IUE-labeled GFP⁺ astrocyte. F2, Immunostaining for NeuN, showing most hole-like structures in F1 (arrows) are occupied by neurons (F2). F3, Merged view. These neurons are tdTomato^-, indicating that they originated from PDs other than Nkx2.1⁺ PD. G, IUE-labeled GFP⁺ astrocytes (G1) and those from Nkx2.1⁺ PD (G2) in the olfactory tubercle. G3 is a merged view. In this region, intermingled distribution of tdTomato⁺ and GFP⁺ astrocytes was observed. However, there is no overlap of their processes. White arrow in G2 points to a hole-like structure. H, Schematic illustration of a neuron from the Nkx2.1⁺ PD (red) is contacted by an astrocyte from a distinct PD (green). I, Schematic illustrating astrocytes from two distinct PDs are associated, intermingled without invading the territory of those from other PDs. Astrocytes with different colors represent those from distinct PDs. Scale bars: 100 μm in A–C, 20 μm in D, E and F, and, 50 μm in G.