Novel Roles of Sonic Hedgehog Signaling in Retinal Patterning and Neurogenesis During Mammalian Eye Development.

The Sonic Hedgehog (Shh) signaling pathway is essential for the patterning, growth, and morphogenesis of many tissues. During early eye development, Shh is critical for the formation of the two optic vesicles, which give rise to the retina, retinal pigment epithelium (RPE), and optic stalk. It also regulates the balance between cell proliferation and differentiation during retinal histogenesis, a key process in shaping the cellular architecture of the mature retina.

MicroRNA Signatures of the Developing Primate Fovea.

Rod and cone photoreceptors differ in their shape, photopigment expression, synaptic connection patterns, light sensitivity, and distribution across the retina. Although rods greatly outnumber cones, human vision is mostly dependent on cone photoreceptors since cones are essential for our sharp visual acuity and color discrimination. In humans and other primates, the (fovea), a specialized region of the central retina, contains the highest density of cones.

Let-7 regulates cell cycle dynamics in the developing cerebral cortex and retina.

In the neural progenitors of the developing central nervous system (CNS), cell proliferation is tightly controlled and coordinated with cell fate decisions. Progenitors divide rapidly during early development and their cell cycle lengthens progressively as development advances to eventually give rise to a tissue of the correct size and cellular composition. However, our understanding of the molecules linking cell cycle progression to developmental time is incomplete.

A Novel Reporter Mouse Uncovers Endogenous Brn3b Expression.

Brn3b () is a class-4 POU domain transcription factor known to play central roles in the development of different neuronal populations of the Central Nervous System, including retinal ganglion cells (RGCs), the neurons that connect the retina with the visual centers of the brain. Here, we have used CRISPR-based genetic engineering to generate a Brn3b-mCherry reporter mouse without altering the endogenous expression of Brn3b. In our mouse line, mCherry faithfully recapitulates normal Brn3b expression in the retina, the optic tracts, the midbrain tectum, and the trigeminal ganglia.