Submitted on September 3, 2008
Revised on November 30, 2008
Accepted on December 2, 2008
Effects of Stanniocalcin 1 on calcium uptake in zebrafish (Danio rerio) embryo
Deng-Yu Tseng1, Ming-Yi Chou1, Yung-Che Tseng2, Chung-Der Hsiao1, Chang-Jen Huang1, Toyoji Kaneko3, and Pung-Pung Hwang4*
1 Academia Sinica
2 National Taiwan University
3 University of Tokyo
4 Institute of Cellular and Organismic Biology, Academia Sinica
* To whom correspondence should be addressed. E-mail: pphwang{at}gate.sinica.edu.tw.
Stanniocalcin (STC, formerly called hypocalcin or teleocalcin) is a 50-kDa disulfide-linked homodimeric glycoprotein that was originally identified in fish and secreted from the corpuscles of Stannius (CS). One of the main functions of STC-1 is Ca2+ uptake inhibition; however the mechanisms remain unknown. In the present study, we provide molecular evidence to elucidate how zebrafish STC-1 regulates Ca2+ uptake in zebrafish embryos. zstc-1 was expressed in a wide variety of tissues including the kidney, brain, gill, muscle, and skin. Incubating zebrafish embryos in low-Ca2+ (0.02 mM) freshwater stimulated whole-body Ca2+ influx and zebrafish epithelial Ca2+ channel (zECaC) mRNA expression while down-regulated zstc-1 expression. A morpholino microinjection approach was used to knockdown the zSTC-1 protein, and the results showed that the Ca2+ content, Ca2+ influx, and zECaC mRNA expression all increased in morphants. These data suggest that zSTC-1 negatively regulates epithelial Ca2+ channel (ECaC) gene expression to reduce Ca2+ uptake in zebrafish embryos.
