PUBLICATION

Unexpected diversity and photoperiod dependence of the zebrafish melanopsin system

Authors
Matos-Cruz, V., Blasic, J., Nickle, B., Robinson, P.R., Hattar, S., and Halpern, M.E.
ID
ZDB-PUB-111021-2
Date
2011
Source
PLoS One   6(9): e25111 (Journal)
Registered Authors
Halpern, Marnie E., Matos-Cruz, Vanessa
Keywords
none
MeSH Terms
  • Animals
  • Gene Expression Regulation
  • Larva/genetics
  • Larva/metabolism
  • Photoperiod*
  • Phylogeny
  • Pineal Gland/metabolism
  • Retina/metabolism
  • Retinal Ganglion Cells/metabolism
  • Rod Opsins/classification
  • Rod Opsins/genetics
  • Rod Opsins/metabolism*
  • Zebrafish/genetics
  • Zebrafish/metabolism*
  • Zebrafish Proteins/classification
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed
21966429 Full text @ PLoS One
Abstract
Animals have evolved specialized photoreceptors in the retina and in extraocular tissues that allow them to measure light changes in their environment. In mammals, the retina is the only structure that detects light and relays this information to the brain. The classical photoreceptors, rods and cones, are responsible for vision through activation of rhodopsin and cone opsins. Melanopsin, another photopigment first discovered in Xenopus melanophores (Opn4x), is expressed in a small subset of retinal ganglion cells (RGCs) in the mammalian retina, where it mediates non-image forming functions such as circadian photoentrainment and sleep. While mammals have a single melanopsin gene (opn4), zebrafish show remarkable diversity with two opn4x-related and three opn4-related genes expressed in distinct patterns in multiple neuronal cell types of the developing retina, including bipolar interneurons. The intronless opn4.1 gene is transcribed in photoreceptors as well as in horizontal cells and produces functional photopigment. Four genes are also expressed in the zebrafish embryonic brain, but not in the photoreceptive pineal gland. We discovered that photoperiod length influences expression of two of the opn4-related genes in retinal layers involved in signaling light information to RGCs. Moreover, both genes are expressed in a robust diurnal rhythm but with different phases in relation to the light-dark cycle. The results suggest that melanopsin has an expanded role in modulating the retinal circuitry of fish.
Genes / Markers
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping