摘要
采用生物信息学方法,从东方(Fugurubripes)基因组中分离出两种不同基因编码的GHR1(fGHR1)和GHR2(fGHR2)。随后设计引物,采用RT-PCR和SmartTMRace相结合的方法从南方鲇(Silurusmeridionalis)肝脏中克隆出两种不同基因编码的生长激素受体,即GHR1(scGHR1)和GHR2(scGHR2)cD-NA,其全长分别为1985bp(编码602个氨基酸)和2300bp(编码553个氨基酸)。这两种受体都含有生长激素受体典型的标志性基序FGDFS,以及细胞内属于细胞因子受体家族共有的Box1和Box2序列框。同时两者又存在差异,表现在胞外半胱氨酸残基和胞内酪氨酸残基数目的不同。采用半定量RT-PCR方法研究了scGHR1和scGHR2在南方鲇各组织中表达量的差异,结果表明:scGHR1和scGHR2有广泛的组织分布,在肝脏中两者的表达量最高。用17β-雌二醇(E2)、17α-甲基睾酮(MT)和可的松(cortisol)对南方鲇进行药物处理,结果表明E2能够下调肝脏scGHR1和scGHR2mRNA水平,而MT上调scGHR1和scGHR2mRNA水平。同时,经cortisol处理后scGHR1mRNA表达水平上升,而scGHR2mRNA表达水平不变。
Two genomic contigs of putative growth hormone receptors （fGHR1 and fGHR2） were identified in the fugu Fugu rubripes genome by in silico analysis, suggesting the presence of two GHR types in a single teleost species. We validated this hypothesis by cloning the cDNA sequences of GHR1 （sd3HR1） and GHR2 （scGHR2） from liver of the Southern catfish Silurus meridionalis by RT-PCR and SmartTM Race. The full-length cDNAs of scGHR1 and scGHR2 are 1 985 bp and 2 300 bp, encoding putative proteins of 602 and 553 amino acids, respectively. Both scGHR1 and scGHR2 have the characteristic landmarks of conventional GHR including the ligand binding motif FGDFS in the extracellular domain and conserved cytoplasmic Boxl and Box2 regions. However, they possess features that are distinctly different from each other. Firstly, the number of extracellular cysteine residues is different. While scGHR1 possesses 7 extracellular cysteine residues forming three disulfide bonds, scGHR2 has only 4 that may form two disulfide bonds. Secondly,the number of intracellular tyrosine residues is different. The scGHR1 contains 8 tyrosine residues, but scGHR2 contains only 5. The expressions of scGHR1 and scGHR2 in different tissues of the Southern catfish were further examined using semi-quantitative RT-PCR. Results showed that scGFIR1 and scGI-/R2 were present in all the tissues examined and that expression of scGHR1 and scGHR2 in liver were higher than in other tissues. In vivo hormonal regulation data indicated that hepatic scGHR1 and scGHR2 mRNA levels were downregulated by 17β-estradiol and upregulated by 17α-methyltestosterone. On the other hand, cortisol upregulated the hepatic scGHR1 mRNA level, but had no effect on levels of scGHR2 mRNA .
出处
《动物学报》
SCIE
CAS
CSCD
北大核心
2006年第6期1096-1106,共11页
ACTA ZOOLOGICA SINICA
基金
教育部重点项目(No.2004-104161)
重庆市科委自然科学基金(No.CSTC2004BB8450)~~
关键词
南方鲇
生长激素受体
结构分析
组织分布
激素调节
Southern catfish, Silurus meridionalis, Growth hormone receptor, Structure analysis, Tissue distribution, Hormonal regulation
