Fig. 2.

Amoeboid microglia clusters are derived from local microglia precursors and develop normally in the absence of blood monocytes. a Scheme of experimental setup. Cx3cr1^CreER:R26-yfp mice were injected intraperitoneally (i.p.) with tamoxifen at P1. Analysis was performed at P7. Representative blot of flow cytometric analysis of whole brain microglia (CD45^lo, CD11b⁺) and subsequent immunofluorescent analysis of brain slices, Iba-1 (red), CX₃CR1 (eYFP), and DAPI (blue). Arrows show triple positive cells. Scale bar 50 μm. b Representative immunofluorescent images of the developing corpus callosum of P7 Ccr2^RFP mice. The P7 choroid plexus was used as a CCR2-RFP positive control. Iba-1 (green), Mac3 (red), CCR2-RFP (white), and DAPI (blue). Arrow shows a triple positive cell next to an Iba-1⁺ macrophage (asterisk). Scale bar 50 μm. c Representative images of Iba-1 immunohistochemistry in brain slices of P7 Wildtype (Wt), Ccr2^−/−, and Nr4a1^−/− mice. Scale bar 50 μm. d Quantification of Iba-1⁺ microglia in the corpus callosum, cortex, and cerebellum of P7 (upper lane) and P42 (lower lane) Wildtype (Wt), Ccr2^−/−, and Nr4a1^−/− mice (n = 3–7). Each symbol represents one mouse. Means with SEM are represented. Samples were collected from two independent experiments