Identification of the growth hormone receptor in an advanced teleost, the tilapia (Oreochromis mossambicus) with special reference to its distinct expression pattern in the ovary
Identification of the growth hormone receptor in an advanced teleost, the tilapia (Oreochromis mossambicus) with special reference to its distinct expression pattern in the ovary
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DOI：
10.1677/joe.0.1810065
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发表时间：
2004-04-01
影响因子：
4
通讯作者：
Aida, K
中科院分区：
文献类型：
--
作者：
Kajimura, S;Kawaguchi, N;Aida, K
有大量证据表明GH/IGF-I轴在女性生殖中起着重要作用。本文报道了生长激素受体（GH-R）的分离、鉴定及其在罗非鱼卵子发生过程中的基因表达谱。从罗非鱼肝脏中克隆了生长激素受体（GH-R）的cDNA序列。预测的GH-R前蛋白由635个氨基酸组成，包含一个推定的信号肽，一个具有特征性基序的胞外区，一个单一的跨膜区，和一个具有保守盒1和2结构域的胞质区。罗非鱼GH-R与已知脊椎动物GH-R的同源性为34-74%。利用COS-7细胞进行的结合试验表明，克隆的GH-R与罗非鱼GH特异性结合。北方印迹分析显示，在肝脏和卵巢的单一mRNA转录。原位杂交结果显示，在小型卵母细胞的胞质和胞核中有较强的GH-R信号。卵黄发生卵母细胞周围的颗粒细胞和卵泡膜细胞也含有GH-R mRNA信号。未成熟卵母细胞中GH-R mRNA的水平比成熟卵母细胞高约10倍，沿着高水平的IGF-I mRNA。在卵母细胞发育过程中，肝脏中GH-R和IGF-I的mRNA水平或血浆IGF-I水平没有显著变化。肝脏GH-R mRNA与卵巢GH-R mRNA之间无相关性。这些结果表明，GH/IGF-I轴在卵巢可能参与卵子发生的早期阶段，从肝脏的GH-R基因表达的不同的调节机制。
There is considerable evidence that the GH/IGF-I axis plays an important role in female reproduction. We report the isolation and characterization of the GH receptor (GH-R) and its gene expression profile during oogenesis in the tilapia, Oreochromis mossambicus. cDNA encoding GH-R was cloned and sequenced from the tilapia liver. The predicted GH-R preprotein consisted of 635 amino acids and contained a putative signal peptide, an extracellular region with a characteristic motif, a single transmembrane region, and a cytoplasmic region with conserved box 1 and 2 domains. he tilapia GH-R shared 34-74% identities with known GH-Rs in vertebrates. A binding assay using COS-7 cells showed that the cloned GH-R bound specifically to tilapia GH. Northern blot analysis showed a single mRNA transcript in the liver and ovary. hi situ hybridization revealed intense signals of GH-R in the cytoplasm and nucleus of miniature oocytes. The granulosa and theca cells surrounding vitellogenic oocytes also contained the GH-R rnRNA signals. About a tenfold greater level of GH-R mRNA was found in the immature oocytes versus the mature oocytes, along with high levels of IGF-I mRNA. There were no significant changes in mRNA levels of GH-R and IGF-I in the liver or in plasma IGF-I levels during oocyte development. No correlation was found between hepatic GH-R mRNA and ovarian GH-R- mRNA. These results suggest that the GH/IGF-I axis in the ovary may be involved in the early phases of oogenesis, under a different regulatory mechanism of GH-R gene expression from that of the liver.