Fig. 4

Microglia morphology is not altered by intrinsic Nf1 reduction A: CX3CR1-Cre^ER mice were intercrossed with Nf1^flox/flox and R26R-EYFP to obtain litters that carry a heterozygous knock-in of Cre^ER at the CX3CR1 locus, a heterozygous knock-in of a flox cassette in the Nf1 locus, and a homozygous, floxed eYFP transgene in the Rosa26 locus (Nf1^flox/wtCx3cr1-Cre^ER). Tamoxifen was administered between P30 and P40 on five consecutive days to activate Cre recombinase in microglia. B: Confocal microscopic images indicating the successful induction of microglial YFP reporter expression by tamoxifen treatment in the cortex of two male WT mice. All scale bars are 20 µm. C: Left, 3-dimensional renderings of example male and female WT and Nf1^flox/wtCx3cr1-Cre^ER microglia in the somatosensory and parts of the motor cortex (layer 2–6). Scale bars denote 20 µm. Right, Sholl analysis of male (top) and female (bottom) WT and Nf1^flox/wtCx3cr1-Cre^ER microglia. The number of intersected processes was plotted against their distance from the soma. There was no difference in the distribution of process branches around the soma between the four investigated groups. D-F: Summary of the number of intersections per cell (D), the total process length (E) and the soma volumes (F) for male and female WT and Nf1^flox/wtCx3cr1-Cre^ER microglia. Number of quantified cells (mice): 50 (3) for each group