Abstract
Melatonin production in the pineal organ and retina is controlled by both light-dark cycles and a circadian clock via the oscillating activity of arylalkylamine N-acetyltransferase (AANAT) in most vertebrates. However, this clock regulation is absent in the rainbow trout (Oncorhynchus mykiss) pineal organ: the trout has two different AANAT genes (AANAT1 and AANAT2), and AANAT2 mRNA levels in the pineal organ did not exhibit circadian oscillation In this study, we confirmed by RT-PCR analysis that AANAT1 is expressed only in the retina, while AANAT2 is expressed in the pineal organ and brain. Real-time quantitative PCR analysis demonstrated that AANAT1 mRNA levels in the retina exhibited daily variations with high levels during the dark phase under light-dark cycles, but kept high and low titers under constant darkness and constant light, respectively. Thus, AANAT1 gene expression in the trout retina is regulated not by a circadian clock but by lighting conditions. (C) 2000 Lippincott Williams and Wilkins.
Original language | English (US) |
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Pages (from-to) | 3473-3477 |
Number of pages | 5 |
Journal | Neuroreport |
Volume | 11 |
Issue number | 16 |
DOIs | |
State | Published - Nov 9 2000 |
Keywords
- Arylalkylamine N-acetyltransferase
- Circadian clock
- Light-dark cycles
- Melatonin
- Rainbow trout
- Real-time quantitative PCR
- Retina
ASJC Scopus subject areas
- General Neuroscience