Cloning of two members of the calcitonin-family receptors from stingray, Dasyatis akajei Possible physiological roles of the calcitonin family in osmoregulation
Cloning of two members of the calcitonin-family receptors from stingray, Dasyatis akajei Possible physiological roles of the calcitonin family in osmoregulation
复制标题
从黄貂鱼 Dasyatis akajei 中克隆降钙素家族受体的两个成员 降钙素家族在渗透压调节中的可能生理作用
作者：
Suzuki N;Sekiguchi T;Satake H;Kato K;Nishiyama Y;Takahashi H;et al
在软骨鱼类中，两个编码降钙素家族受体的cDNA首次从黄貂鱼脑中分离出来。一个受体cDNA的开放阅读框编码一个525个氨基酸的蛋白质。该受体与人降钙素受体样受体（CRLR）、青蛙CRLR和比目鱼CRLR的氨基酸同源性分别为64.5%、64.7%和61.2%，高于与人降钙素受体（CTR）、青蛙CTR和比目鱼CTR的氨基酸同源性（分别为46.1%、54.7%和48.9%）。系统发育分析表明，该受体可能是一种射线CRLR。在第二种受体的情况下，CRLR（人50.5%，青蛙50.7%，比目鱼48.0%）和CTR（人43.2%，青蛙49.1%，比目鱼41.8%）之间的氨基酸同一性相似。从CRLR和CTR的系统发育分析，我们认为该受体是射线CTR。射线CRLR mRNA主要在神经系统（脑）和血管系统（心房、心室和鳃）中表达，反映了CGRP在神经和血管系统中的定位与哺乳动物相似。观察到第二受体在几种组织中表达，即软骨、脑、垂体、鳃、心房、心室、胰腺、脾、肝、胆囊、肠、直肠腺、肾、睾丸和卵巢。这种定位模式与比目鱼CTR非常相似。两种受体mRNA在鳃中均强烈表达。这表明降钙素家族成员参与黄貂鱼的生长调节，因为这种鱼是广盐性的。当黄貂鱼转移到稀释海水（20%海水）中时，鳃中两种受体的表达均显着下降。在黄貂鱼的肾脏中也得到了类似的结果。因此，我们在黄貂鱼中克隆和分离这两种受体将有助于阐明它们的生理功能，如钙调节，包括软骨鱼类的钙代谢。
In cartilaginous fish, two cDNAs encoding calcitonin-family receptors were isolated for the first time from the stingray brain. The open reading frame of one receptor cDNA coded a 525-amino acid protein. The amino acid identity of this receptor to human calcitonin-receptor-like receptor (CRLR) is 64.5%, frog CRLR is 64.7%, and flounder CRLR is 61.2% and this was higher than to human calcitonin receptor (CTR) (46.1%), frog CTR (54.7%), and flounder CTR (48.9%). We strongly suggested that this receptor is a ray CRLR based on phylogenetic analysis. In case of the second receptor, amino acid identity among CRLRs (human 50.5%, frog 50.7%, flounder 48.0%) and CTRs (human 43.2%, frog 49.1%, flounder 41.8%) was similar. From phylogenetic analysis of both CRLRs and CTRs, we believe that this receptor is ray CTR. The expression of ray CRLR mRNA was predominantly detected in the nervous system (brain) and vascular system (atrium, ventricle, and gill), which reflects the similar localization of CGRP in the nervous and vascular systems as mammals. It was observed that the second receptor was expressed in several tissues, namely cartilage, brain, pituitary gland, gill, atrium, ventricle, pancreas, spleen, liver, gall bladder, intestine, rectal gland, kidney, testis and ovary. This localization pattern was very similar to flounder CTR. Both receptor mRNAs were strongly expressed in the gill. This suggests that the calcitonin-family members are involved in the osmoregulation of stingray as this fish is known to be euryhaline. When a stingray was transferred to diluted seawater (20% seawater), the expression of both receptors significantly decreased in the gill. Similar results were obtained in the kidney of the stingray. Thus, our cloning and isolation of both receptors in the stingray will be helpful for elucidation of their physiological role(s) such as osmoregulation including calcium metabolism of cartilaginous fish.