Abstract :
In this study, we have determined the partial nucleotide sequence of calcitonin receptor (CTR) from the scales of goldfish (Carassius auratus). The obtained goldfish CTR cDNA coded a 502-amino-acid protein. The amino acid identity of goldfish CTR to medaka CTR and flounder CTR is 57.9 % and 49.9%, respectively, and this was higher than the calcitonin-receptor-like receptor (CLR) in medaka (42.1%) and flounder (39.1%). Judging from phylogenetic analysis, we confirmed that this receptor is goldfish CTR. In mammals, it has been known that CTR is one of osteoclastic markers. To examine that CTR is a functional osteoclastic marker in goldfish as well as in mammals, we examined relationship between tartrate-resistant acid phosphatase activity (TRAP) represented as an osteoclastic activity and CTR mRNA expression. TRAP activities and CTR mRNA expressions in regenerating scales were significantly higher than those in ontogenic scales. In addition, the positive co-relationship between TRAP activities and CTR mRNA expressions was recognized. Thus, we conclude that CTR in goldfish scales is a functional osteoclastic marker and suggest that expression analysis of CTR in goldfish scales can contribute to the investigation of several physiological phenomena in fish bone metabolism.
Keyword :
Calcitonin receptor, Osteoclasts, Goldfish scales, mRNA expression, Tartrate-resistant acid phosphatase