Figure 1.

Sepp1 binds to apoER2 in d 18 fetal brain capillaries (Cap) and choroid plexus (CP). Sepp1 is stained red, apoER2 is stained green, and nuclei are stained blue. A–C) Views of the same fetal brain cortex section. Section stained for Sepp1 (A), section stained for apoER2 (B), and a merge of A and B (C). D) Brain cortex of an apoER2^−/− mouse stained for Sepp1. E, F) CP in a lateral ventricle and the adjacent ventricle wall stained for Sepp1. Section from a wild-type mouse (E) and section from an apoER2^−/− mouse (F). CD 31 staining was used to verify the identity of capillaries (not shown).