PUBLICATION
Transcripts encoding two melatonin synthesis enzymes in the teleost pineal organ: circadian regulation in pike and zebrafish, but not in trout
- Authors
- Bégay, V., Falcón, J., Cahill, G.M., Klein, D.C., and Coon, S.L.
- ID
- ZDB-PUB-980313-2
- Date
- 1998
- Source
- Endocrinology 139: 905-912 (Journal)
- Registered Authors
- Cahill, Greg, Klein, David C.
- Keywords
- circadian rhythms, pineal body, rna, messenger, salmo trutta, zebrafish, enzymes, melatonin biosynthetic process
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Arylamine N-Acetyltransferase/genetics*
- Circadian Rhythm*
- Esocidae/metabolism
- Female
- Fishes/metabolism*
- Gene Expression Regulation*
- Male
- Melatonin/biosynthesis*
- Molecular Sequence Data
- Organ Culture Techniques
- Pineal Gland/metabolism*
- RNA, Messenger/analysis*
- Trout/metabolism
- Zebrafish/metabolism
- PubMed
- 9492019 Full text @ Endocrinology
Citation
Bégay, V., Falcón, J., Cahill, G.M., Klein, D.C., and Coon, S.L. (1998) Transcripts encoding two melatonin synthesis enzymes in the teleost pineal organ: circadian regulation in pike and zebrafish, but not in trout. Endocrinology. 139:905-912.
Abstract
In this report the photosensitive teleost pineal organ was studied in three teleosts, in which melatonin production is known to exhibit a daily rhythm with higher levels at night; in pike and zebrafish this increase is driven by a pineal clock, whereas in trout it occurs exclusively in response to darkness. Here we investigated the regulation of messenger RNA (mRNA) encoding serotonin N-acetyltransferase (AA-NAT), the penultimate enzyme in melatonin synthesis, which is thought to be primarily responsible for changes in melatonin production. AA-NAT mRNA was found in the pineal organ of all three species and in the zebrafish retina. A rhythm in AA-NAT mRNA occurs in vivo in the pike pineal organ in a light/dark (L/D) lighting environment, in constant lighting (L/L), or in constant darkness (D/D) and in vitro in the zebrafish pineal organ in L/D and L/L, indicating that these transcripts are regulated by a circadian clock. In contrast, trout pineal AA-NAT mRNA levels are stable in vivo and in vitro in L/D, L/L, and D/D. Analysis of mRNA encoding the first enzyme in melatonin synthesis, tryptophan hydroxylase, reveals that the in vivo abundance of this transcript changes on a circadian basis in pike, but not in trout. A parsimonious hypothesis to explain the absence of circadian rhythms in both AA-NAT and tryptophan hydroxylase mRNAs in the trout pineal is that one circadian system regulates the expression of both genes and that this system has been disrupted by a single mutation in this species.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping