Extended Data Figure 6. Lineage tracing of AAV-Cre activity after direct injection into the mouse brain.

AAV-Cre virus was injected into the brain of Ai14 Cre reporter animals and Cre activity assessed by detection of the tdTomato (RFP) reporter 14 days after injection. a-c, Confocal microscopic overview from a, the injection site; b, the border region of the viral spread and c, the contralateral cortex of AAV-Cre injected Ai14 mice two weeks after stereotactic injection. AAV-Cre transduced cells expressed red fluorescent protein (RFP) (shown in white). RFP-positive vessels were identified by colocalization with PECAM1 (shown in red). White arrows point to representative RFP-positive vessels. Yellow arrowheads point to RFP-expressing neuronal cells. Scale bar, 100 microns. Boxed regions in 1 and 2 are shown at higher magnification on the right. 1 & 2 show PECAM1 staining for endothelial cells overlaid with RFP signal; 1’ & 2’ show PECAM staining alone; 1” & 2” shown RFP staining alone. These data are representative 12 separate images from 8 tissue sections from n=2 individual animals. Scale bar, 20 microns.