Early Photoreceptor Precursor Cells (RNL)

Photoreceptor precursor cells are post-mitotic precursor cells which can differentiate into cones or rods, that eventually express different photopigments (M opsin or S opsin in cones, and rhodopsin in rods). In humans, all photoreceptors are prenatally generated. However, in the mouse, cones are formed at early embryonic stages, while rods are formed both prenatally and postnatally.

The photoreceptor precursor cell follows a default pathway to differentiate into an S cone, unless additional regulatory signals direct the precursor into an M cone or rod fate.