Fig. 2.

EphB forward signaling is required for normal axon guidance in the VTel. L1-CAM–immunolabeled coronal sections of (A) EphB1^−/−EphB2^−/−, (B) EphB1^Tr/Tr, (C) EphB2^Tr/Tr, or (D) EphB1^Tr/TrEphB2^Tr/Tr mutant mice at P0. The axon guidance errors in the VTel are noted with yellow arrows. In the EphB1^Tr/TrEphB2^Tr/Tr mice, evidence of a misprojected posterior branch of the anterior commissure is noted by yellow arrowhead. (E and F) Injection of the EphB kinase inhibitor, 1-NA-PP1, from E12–E19 produced VTel axon guidance errors. (G) Quantification of VTel axon guidance errors, as described in SI Methods. **P < 0.01, ****P < 0.0001, Fisher’s exact test (Fig. S2).