Figure 12.

Schematic diagram illustrating gene interactions hypothesized to regulate the formation of the ipsilateral retinofugal pathway. Zic2 specifies ipsilateral fate by driving EphB1 expression (arrow). EphB1 expression causes axons to project ipsilaterally at the chiasmatic midline. In the ventral retina, Ten-m2 is also required for EphB1 expression (arrow) and converts a contralateral mapping program to an ipsilateral one in this region. This may occur downstream, or independently, of Zic2 expression (dotted arrow). Further, Zic2 drives Sert expression to regulate segregation (arrow). This interaction is independent of the potential Zic2-Ten-m2-EphB1 pathway. Arrows may indicate direct or indirect regulation (schema based on data in Herrera et al., 2003, Williams et al., 2003; García-Frigola et al., 2008; Rebsam et al., 2009, 2012; García-Frigola and Herrera, 2010 as well as current study).