Figure 2. Sox6 expression defines a dorsal-ventral division of the murine SNc.

(A) Simultaneous intersectional/subtractional genetic labeling strategy.

(B) Example of an adult Sox6-FSF-Cre, Th-2A-flpo, RC-Frepe brain. Some mCherry⁺ cells are observed above the SNc, lacking TH immunoreactivity (*).

(C) Average number of TH⁺,mCherry⁺ (red bars) and TH⁺,GFP⁺ (green bars) in the main DA neuron areas. p values: SNc = 0.014, SNpl = 0.004, VTA = 0.008.

(D) Histogram of spatial coordinates of TH⁺,GFP⁺ or TH⁺,mCherry⁺ cells; TH⁺,mCherry⁺ neurons are biased dorsally.

(E) Left: histogram of spatial coordinates of TH⁺,GFP⁺ or TH⁺,mCherry⁺ cells normalized to total TH⁺,GFP⁺ or TH⁺,mCherry⁺ cells. Right: centroid of GFP⁺ and mCherry⁺ populations for each section of each mouse included in left panel (4 sections per brain) (p = 6 × 10⁻⁷).

(F) GFP⁺ cells co-express ALDH1A1 (SNc).

(F’) Percentage of GFP⁺ (Sox6⁺) and mCherry⁺ (Sox6⁻) neurons co-expressing ALDH1A1 in the SNc. p = 0.02.

(G) Most mCherry⁺ cells express CALBINDIN-D28k (CB) (SNc). CB signal intensity varies from low (yellow arrowhead) to high (white arrowhead).

(G’) Percentage of GFP⁺ (Sox6⁺) and mCherry⁺ (Sox6⁻) neurons co-expressing CB in the SNc. p = 0.0007.

Scale bars: 200 μm. Error bars (C’, F’, and G’) and shaded areas (D and E) are SEMs. S⁺: Sox6⁺, S⁻: Sox6⁻. (A)–(E) n = 5, (F) and (G) n = 3.