Li Shuisheng, Liu Qiongyu, Xiao Ling, Chen Huapu, Li Guangli, Zhang Yong, Lin Haoran
Zhanjiang City State Key Laboratory of Marine Ecology and Environment, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China; State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and the Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, Guangzhou 510275, China.
Comp Biochem Physiol B Biochem Mol Biol. 2016 Jun-Jul;196-197:85-91. doi: 10.1016/j.cbpb.2016.02.009. Epub 2016 Mar 2.
Spexin is a newly discovered neuropeptide in vertebrates. Comprehensive comparative studies are required to unveil its biological functions. In order to ascertain the neuroendocrine function of spexin in orange-spotted grouper, its full-length cDNA and genomic DNA sequences were cloned and analyzed. Sequence analyses showed that the spexin gene structure is composed of six exons and five introns, and the amino acids of mature peptide (spexin-14) in grouper are identical to that of other fish. Tissue expression analysis found that grouper spexin is highly expressed in the brain, liver and ovary. Real time-PCR analysis demonstrated that the hypothalamic expression of spexin declined gradually during the ovarian development, and was up-regulated by food deprivation. Intraperitoneal administration of spexin-14 peptides to grouper significantly elevated the mRNA levels of proopiomelanocortin (pomc) and suppressed the orexin expression in the hypothalamus, but could not change the hypothalamic expression of gonadotropin releasing hormone 1 (gnrh1). Both in vivo and in vitro administration of spexin could not significantly influence the expression of follicle-stimulating hormone β (fshβ) and luteinizing hormone β (lhβ) in the pituitary with the exception of an inhibition of gh expression. Our data suggested that the spexin has a significant role in the regulation of energy metabolism and food intake in orange-spotted grouper.
鲷鱼毒素是脊椎动物中新发现的一种神经肽。需要进行全面的比较研究来揭示其生物学功能。为了确定鲷鱼毒素在斜带石斑鱼中的神经内分泌功能，克隆并分析了其全长cDNA和基因组DNA序列。序列分析表明，鲷鱼毒素基因结构由6个外显子和5个内含子组成，石斑鱼中成熟肽（鲷鱼毒素-14）的氨基酸与其他鱼类相同。组织表达分析发现，石斑鱼鲷鱼毒素在脑、肝和卵巢中高表达。实时荧光定量PCR分析表明，鲷鱼毒素在下丘脑的表达在卵巢发育过程中逐渐下降，并在饥饿时上调。腹腔注射鲷鱼毒素-14肽可显著提高促肾上腺皮质激素原（pomc）的mRNA水平，并抑制下丘脑食欲素的表达，但不能改变促性腺激素释放激素1（gnrh1）在下丘脑的表达。除了抑制生长激素（gh）的表达外，体内和体外注射鲷鱼毒素均不能显著影响垂体中促卵泡激素β（fshβ）和促黄体生成素β（lhβ）的表达。我们的数据表明，鲷鱼毒素在斜带石斑鱼的能量代谢和食物摄入调节中具有重要作用。
