Circadian clock genes of goldfish, Carassius auratus: cDNA cloning and rhythmic expression of period and cryptochrome transcripts in retina, liver, and gut.
Clock genes are known to be the molecular core of biological clocks of vertebrates. They are expressed not only in those tissues considered central pacemakers, but also in peripheral tissues. In the present study, partial cDNAs for 6 of the principal clock genes (Period 1-3 and Cryptochrome 1-3) were cloned from a teleost fish, the goldfish (Carassius auratus ). These genes showed high homology (approximately 90%) with the respective cDNAs of zebrafish (Danio rerio), the only other teleost from which clock genes have been cloned. The daily expression pattern of each gene in retina, gut, and liver of goldfish was investigated using quantitative RT-PCR and cosinor analysis. All clock genes analyzed in the retina showed circadian rhythmicity; however, only Per 2-3 and Cry 2-3 were rhythmic in goldfish liver and gut. The amplitude and phase of the expression in liver and gut were different from those found in goldfish retina. Such differences suggest that other cues, such as feeding time, may contribute to the entrainment of oscillators in goldfish liver and gut. Our results support the use of goldfish as a teleost model to investigate the location and functioning of the circadian oscillators.
Department of Physiology (Animal Physiology II), Faculty of Biology, Complutense, University of Madrid, Madrid, Spain.
E
E
Velarde
R
R
Haque
P M
PM
Iuvone
C
C
Azpeleta
A L
AL
Alonso-Gómez
M J
MJ
Delgado
D000818:Animals; D001683:Biological Clocks / Q000235:genetics*; D002940:Circadian Rhythm / Q000235:genetics*; D003001:Cloning, Molecular; D056931:Cryptochromes; D005420:Flavoproteins / Q000235:genetics / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000166:cytology / Q000502:physiology; D005786:Gene Expression Regulation; D006054:Goldfish / Q000033:anatomy & histology / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000502:physiology; D008969:Molecular Sequence Data; D056950:Period Circadian Proteins; D012160:Retina / Q000166:cytology / Q000502:physiology; D014018:Tissue Distribution; D029961:Zebrafish Proteins
D056931:Cryptochromes; D005420:Flavoproteins; D047908:Intracellular Signaling Peptides and Proteins; D056950:Period Circadian Proteins; D029961:Zebrafish Proteins; C539026:per1a protein, zebrafish