Sall3 plays essential roles in horizontal cell maturation through regulation of neurofilament expression levels

► Role of Sall3 in retinal development was examined. ► Lack of horizontal cells was observed in Sall3-KO mice retina. ► Precursor of horizontal cells was present but maturation of neurite extension did not occur. ► Neurofilament protein level was not maintained in the KO. ► Sall3 plays essential roles in horizontal cell maturation in retina.