Differentiation of photoreceptors
Schlosser, Gerhard
Schlosser, Gerhard
Repository DOI
Publication Date
2021-06-18
Keywords
Type
book part
Downloads
Citation
Schlosser, Gerhard. (2021). Differentiation of photoreceptors. In Gerhard Schlosser, Development of sensory and neurosecretory cell types: Vertebrate cranial placodes, Volume 1. Boca Raton: CRC Press.
Abstract
Chapter 7 discusses how photoreceptors and other cells found in the retina of the vertebrate eye or in the pineal body differentiate. These cell types do not develop from cranial placodes but from the neural tube. However, part three of the book will reveal that these cell types are evolutionarily closely related to other sensory cell types (e.g. mechanoreceptors) that are placode derived. To prepare for this argument, this chapter reviews vertebrate photoreceptors and related cell types and summarizes how their specification is transcriptionally regulated. This survey shows that these cells fall into two broad classes suggesting an evolutionary origin from two distinct types of photoreceptors in the vertebrate ancestor. The rods and cones of the retina and most other photoreceptors in the brain (e.g of the pineal body) are ciliary photoreceptors, which rely on ciliary opsin for phototransduction and depend on a core regulatory network (CoRN) involving Rx, Otx2 and Otx5/Crx. Bipolar cells may be evolutionarily derived from such ciliary photoreceptors, but have lost photosensitivity. Intrinsically photosensitive retinal ganglion cells (RGCs), on the other hand, are modified rhabdomeric photoreceptors, which rely on rhabdomeric opsin (melanopsin) and depend on a CoRN involving Pax6, Atoh7, POU4f2 and Islet1. Other RGCs, amacrine and horizontal cells may also be evolutionarily derived from rhabdomeric photoreceptors, but have lost photosensitivity.
Funder
Publisher
CRC Press
Publisher DOI
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International