卵形鲳鲹Kiss1基因组结构特征及饵料类型对其表达的影响

Genomic structure characterization of Kiss1 gene from Trachinotus ovatus and its expression responses to the feed types

Kiss基因编码的kisspeptin多肽是脊椎动物重要的神经激素,在调控机体生长发育、能量代谢和生殖活动中发挥重要作用。为了明确卵形鲳鲹Kiss1 (ToKiss1)基因序列及饵料类型对其表达的影响,实验利用RACE方法克隆分析了ToKiss1基因结构特征,荧光定量PCR (qRT-PCR)方法研究了饵料类型对ToKiss1 mRNA表达调控的影响。结果显示,ToKiss1基因全长2 768 bp,由3个外显子和2个内含子组成。ToKiss1基因cDNA全长505 bp,开放阅读框312 bp,编码104个氨基酸,包括信号肽序列和典型的kisspeptin-10结构域"YNLNSFGLRY"。卵形鲳鲹ToKiss1蛋白三级结构由2个α螺旋和无规则卷曲构成。qRTPCR表达分析结果显示,ToKiss1 mRNA在卵形鲳鲹脑、肠道、胃、脾脏、肌肉和心脏中均有表达,在脑中的表达量最高。饵料类型显著影响ToKiss1 mRNA在卵形鲳鲹肠道组织中的表达,颗粒饲料组表达量最高,其次为冰杂鱼组,冰鱿鱼组表达量最低,但饵料类型对肝脏组织中ToKiss1 mRNA的表达无显著影响,表明ToKiss1在卵形鲳鲹消化吸收过程中发挥了重要调控作用。该研究首次探讨了饵料类型对硬骨鱼肝脏和肠道组织中Kiss1 mRNA表达的影响,为深入研究硬骨鱼类Kiss1基因摄食调控生理机制奠定了基础。

Kisspeptins are a family of neuropeptides encoded by the Kiss genes and play important roles in the reproduction and the regulation energy balance in vertebrate.In order to identify the sequence information of Trachinotus ovatus Kiss1(ToKiss1)and its expression response to the different feed types,ToKiss1 was cloned from the T.ovatus based on its genome sequences and transcriptome sequences,then the expression level of ToKiss1 in liver and intestine tissues were analyzed by qRT-PCR.ToKiss1 is approximately 2 768 bp in length with 3 exons and 2 introns.The whole length of ToKiss1 cDNA was 505 bp,including a 312 bp open reading frame(ORF)encoding 104 amino acids,in which there are a signal peptide and one kisspeptin-10 domain(YNLNSFGLRY).Its tertiary structure consisted of twoα-helices and was similar to a pail.Phylogeny analysis proved that the kisspeptin-1 in Osteichthyes has distant relationship with the kisspeptin-1 in Mammalia,Amph-ibian and Reptilia.The qRT-PCR tissue expression analysis indicated that ToKiss1 mRNA was expressed in brain,intestine,stomach,spleen and muscle with the highest expression level in brain.Feed types significantly affected the expression profile of intestinal ToKiss1 mRNA.The transcription level of intestinal ToKiss1 mRNA in T.ovatus fed with pelleted feed was higher than in those fed with iced fish,and the T.ovatus fed with iced squid had lowest ToKiss1 mRNA expression.However,feed types did not significantly affect the expression profile of hepatic ToKiss1 mRNA.All those results indicated that kisspeptin may play a critical role in digestion and absorption functions of the T.ovatus.The research for the first time focuses on expression difference of ToKiss1 mRNA in liver and intestine of Osteichthyes by feeding different feed types,which benefits further studies on the feeding regulation physiological mechanism of Kiss1 gene of teleost fish.