Fig. 7.

Conditional ephrin-B mutant mice display reduced ipsilateral projections at the optic chiasm. Direct visualization of optic chiasm of P0 mice where one optic nerve (ON) was labeled with DiI diffused from the optic disk (black arrow) to check for the presence (white arrow) or lack (*) of an ipsilateral projection from the optic chiasm (OX). (A–G) Two crosses (shown directly above images) were used to generate specific mutant mice of the following genotypes: ephrin-B1^loxP/Y: ephrin-B2^T/loxP double mutant mice lacking cre recombinase under the hGFAP promoter (A), hGFAP^cre:ephrin-B1^loxP/Y (B), hGFAP^cre:ephrin-B2^T/loxP (C), hGFAP^cre:ephrin-B1^loxP/Y:ephrin-B2^T/loxP (D), ephrin-B2^+/loxP heterozygote mutant mice lacking cre recombinase under the Nestin promoter (E) Nestin^cre:ephrin-B1^loxP/Y (F), and Nestin^cre:ephrin-B2^T/loxP (G). (H) An EphB1^{T-lacZ/T-lacZ} mutant mouse. The ephrin-B2^T mutation produces a truncated form of ephrin-B2 that fails to reach the cell surface and acts as a protein-null (Cowan et al., 2004). Scale bar = 200 µm.