scholarly journals Recruitment of Rod Photoreceptors from Short-Wavelength-Sensitive Cones during the Evolution of Nocturnal Vision in Mammals

2016 ◽  
Vol 37 (6) ◽  
pp. 520-532 ◽  
Author(s):  
Jung-Woong Kim ◽  
Hyun-Jin Yang ◽  
Adam Phillip Oel ◽  
Matthew John Brooks ◽  
Li Jia ◽  
...  
Keyword(s):  
Short Wavelength ◽  
Rod Photoreceptors ◽  
Nocturnal Vision

scholarly journals Nrl is dispensable for specification of rod photoreceptors in adult zebrafish contrasting a deeply conserved requirement earlier in ontogeny

2020 ◽  
Author(s):  
A. Phillip Oel ◽  
Gavin J. Neil ◽  
Emily M. Dong ◽  
Spencer D. Balay ◽  
Keon Collett ◽  
...  
Keyword(s):  
Cell Fate ◽  
Leucine Zipper ◽  
Early Ontogeny ◽  
List Type ◽  
Adult Zebrafish ◽  
Rod Photoreceptors ◽  
Transgenic Expression ◽  
Nocturnal Vision ◽  
Necessary And Sufficient ◽  
Rod Cell

AbstractThe transcription factor NRL (Neural Retinal Leucine-zipper) has been canonized, appropriately enough, as the master regulator of photoreceptor cell fate in the retina. NRL is necessary and sufficient to specify rod cell fate and to preclude cone cell fate in mice. By engineering zebrafish we tested if NRL function has conserved roles beyond mammals or beyond nocturnal species, i.e. in a vertebrate possessing a greater and more typical diversity of cone sub-types. Here, transgenic expression of a Nrl homolog from zebrafish or mouse was sufficient to convert developing zebrafish cones into rod photoreceptors. Zebrafish nrl-/- mutants lacked rods (and had excess UV-sensitive cones) as young larvae, thus the conservation of Nrl function between mice and zebrafish appears sound. These data inform hypotheses of photoreceptor evolution through the Nocturnal Bottleneck, suggesting that a capacity to favor nocturnal vision is a property of NRL that predates the emergence of early mammals. Strikingly, however, rods were abundant in adult nrl-/- null mutant zebrafish. Rods developed in adults despite Nrl protein being undetectable. Therefore a yet-to-be-revealed non-canonical pathway independent of nrl is able to specify the fate of some rod photoreceptors.Highlights- Nrl is conserved and sufficient to specify rod photoreceptors in zebrafish retina- Nrl is necessary for rod photoreceptors in early ontogeny of zebrafish larvae- Zebrafish Nrl is functionally conserved with mouse and human NRL- Remarkably, Nrl is dispensable for rod specification in adult zebrafish

scholarly journals Rod nuclear architecture determines contrast transmission of the retina and behavioral sensitivity in mice

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Kaushikaram Subramanian ◽  
Martin Weigert ◽  
Oliver Borsch ◽  
Heike Petzold ◽  
Alfonso Garcia-Ulloa ◽  
...  
Keyword(s):  
Nuclear Organization ◽  
Nuclear Architecture ◽  
Optical Quality ◽  
Rod Photoreceptors ◽  
Behavioral Sensitivity ◽  
Detection Capabilities ◽  
Nocturnal Vision ◽  
Underlying Mechanisms ◽  
Image Detail ◽  
Nocturnal Mammals

Rod photoreceptors of nocturnal mammals display a striking inversion of nuclear architecture, which has been proposed as an evolutionary adaptation to dark environments. However, the nature of visual benefits and the underlying mechanisms remains unclear. It is widely assumed that improvements in nocturnal vision would depend on maximization of photon capture at the expense of image detail. Here, we show that retinal optical quality improves 2-fold during terminal development, and that this enhancement is caused by nuclear inversion. We further demonstrate that improved retinal contrast transmission, rather than photon-budget or resolution, enhances scotopic contrast sensitivity by 18–27%, and improves motion detection capabilities up to 10-fold in dim environments. Our findings therefore add functional significance to a prominent exception of nuclear organization and establish retinal contrast transmission as a decisive determinant of mammalian visual perception.

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