Reactivating the Zic2-driven transcriptional program restores axon guidance competence during adult CNS regeneration

Axon regeneration in the adult central nervous system can be promoted by reactivating intrinsic growth programs, yet regenerating axons frequently fail to navigate correctly at key choice points, limiting the restoration of precise connectivity. Here, we test whether reactivation of a defined embryonic guidance program can restore trajectory control to regenerating adult neurons. We show that adeno-associated virus–mediated expression of the developmental transcription factor Zic2 in adult mouse retinal ganglion cells induces Eph receptor expression and β-catenin accumulation, reinstating sensitivity to midline repulsive cues. Notably, ephrinB2 and Wnt5a, guidance ligands critical during development, persist at the adult optic chiasm. Whereas regenerating axons navigate stochastically at the chiasm under growth-promoting conditions, Zic2 expression biases axon trajectories away from the midline, redirecting them predominantly into the ipsilateral optic tract. These findings demonstrate that axon trajectory specification represents a reprogrammable dimension of adult CNS regeneration, and that reactivating developmental transcriptional identity programs can restore guidance competence independently of axon growth enhancement.