中华大蟾蜍斯钙素基因的组织表达及其在肾脏中的细胞定位

Tissue expression of stanniocalcin gene and its localization in kidney cells of the toad Bufo bufo gargarizans

斯钙素(Stanniocalcin,STC)是一类首先在鱼类特有的内分泌腺——斯坦尼氏小体(Corpuscles of Stannius,CS)、随后又在人和哺乳动物中发现的同型二聚体糖蛋白激素,具有广泛的组织表达模式和多种生物学效应。为阐明两栖类动物是否存在STC1基因的表达及其表达模式,本研究基于部分已知鱼类和哺乳动物的STC1基因序列,从中华大蟾蜍(Bufo bufo gargarizans)卵巢获得了STC1基因的部分序列(Gen Bank注册号为EF586886)。同源性分析显示,所获得的中华大蟾蜍STC1基因部分序列与鱼类STC1基因相应序列的同源性在40%-48%,而与小鼠和人STC1基因相应序列的同源性分别为41.89%和37.95%。RT-PCR分析显示STC1基因可在肾脏、性腺等多种组织中表达;原位杂交(in situhy bridization,ISH)技术表明中华大蟾蜍肾脏的近端小管、远端小管和集合管细胞内表达STC1mRNA。这些结果首次证实两栖类动物中华大蟾蜍组织中存在STC1基因的表达。

Stannniocalcin （STC） is a homodimeric glycoprotein hormone that was firstly identified as a secretory product of the corpuscle of Stannius （CS）, an endocrine gland unique to bony fish. Later, the mammalian homolog of the STC has been found in humans, rats, and mice. STC shows a diverse tissue expression pattern and many intriguing biological functions. To characterize the expression of the STC1 gene in amphibian, we have cloned and sequenced a partial cDNA of the STC1 gene from the toad Bufo bufo gargarizans ovary based on the known STC1 gene sequences for fish and mammals, and examined its expression pattern in various tissues. The sequence has been submitted to the GenBank database with the accession number EF586886. The sequence analysis of toad STC 1 gene showed moderate sequence identity with those of fish （40 % - 48 % ）, mouse （41.89 % ）, and human （37.95%）, respectively. RT-PCR analysis revealed that the STCI gene was expressed in many organs of toad, including kidney, gonad, brain, liver, heart, intestine, and muscle. With in situ hybridization analysis, STC1 mRNA was located to proximal tubule, distal tubule and collecting duct cells in the toad. In summary, these data provide compelling evidence for the existence of the STC1 gene in the toad ovary