家鸡GPR15基因的克隆、功能探究及组织表达分析

孤儿受体G蛋白偶联受体15(GPR15)在哺乳动物肠道稳态以及炎症反应中发挥重要生理效应,但在非哺乳动物中,针对GPR15的研究几属空白。本文以家鸡Gallus gallus domesticus为模型,首次克隆了GPR15基因,并对其功能与组织表达进行了探究。结果显示:家鸡GPR15编码区cDNA长度为1 107 bp,由1个外显子组成,可编码368个氨基酸的受体蛋白。序列分析表明家鸡GPR15是具有7次跨膜结构的G蛋白偶联受体,且家鸡GPR15与人Homo sapiens、北美绿蜥蜴Anolis carolinensis、小鼠Mus musculus的GPR15具有约56%的氨基酸序列一致性;虽然系统进化树分析表明GPR15与爱帕琳肽受体(APLNR)有较近的进化关系,但在表达家鸡GPR15的HEK293细胞中,APLNR的内源性配体Apelin和Apela不能激活家鸡GPR15;此外,实时定量PCR分析发现GPR15在家鸡脾脏中高表达,在盲肠、肺中有中等水平表达,而在其他组织中微弱表达。上述结果为探究GPR15在禽类中的生理功能奠定了基础。

Characterization of GPR15 Gene in Chicken: Cloning,Functional Analysis and Tissue Distribution

Orphan receptor G protein-coupled receptor 15 (GPR15) has been reported to play important roles in mammals, including intestinal homeostasis and inflammatory responses. However, the information regarding GPR15 in non-mammals remains unknown. In this study, the coding region of chicken GPR15 was cloned, and its function and tissue expression pattern were also investigated. We found that the coding region of chicken GPR15 was 1 107 bp in length, which was consisted of 1 exon encoding a protein of 368 amino acids. Sequence analysis indicated that chicken GPR15 had a seven-transmembrane structure of GPR, which shared about 56% amino acid sequence identity with GPR15 of human (Homo sapiens), anole lizard (Anolis carolinensis) and mouse (Mus musculus). Although phylogenetic analysis showed that the GPR15 and APLNR were closely related, GPR15 failed to be activated by the endogenic ligands of APLNR (Apelin and Apela peptide). Quantitative real-time PCR assay showed that chicken GPR15 was highly expressed in the spleen, moderately expressed in caecum and lung, and weakly expressed in other remaining tissues. Our data lay a foundation for further uncovering the physiological roles of GPR15 in birds.