Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, School of Life Sciences, Sichuan University, Chengdu 610064, People's Republic of China.
Endocrinology. 2012 Apr;153(4):1861-74. doi: 10.1210/en.2011-1719. Epub 2012 Feb 21.
Prolactin-releasing peptide (PrRP) and its structurally related peptide, Carassius Arg-Phe-amide peptide (C-RFa), have been reported to play similar roles in regulating food intake and pituitary functions in vertebrates. However, the identity, functionality, and expression of the receptor(s) for PrRP and C-RFa remain largely unknown in nonmammalian vertebrates, including birds. In this study, three receptors homologous to mammalian PrRP receptor (PrRPR), named cPrRPR1, cPrRPR2, and cC-RFaR, respectively, were cloned from chicken brain by RT-PCR. Using a pGL3-NFAT-RE-luciferase reporter system, we demonstrated that cPrRPR1 and cPrRPR2 expressed in Chinese hamster ovarian cells could be activated by cPrRP₂₀ and cC-RFa₂₀ potently, whereas cC-RFaR could only be activated effectively by cC-RFa₂₀ (EC₅₀, 0.11 nM), indicating that cPrRPR1 and cPrRPR2 can function as common receptors for PrRP and C-RFa, whereas cC-RFaR is a receptor specific to C-RFa. Using a pGL3-CRE-luciferase reporter system, cPrRPR1, cPrRPR2, and cC-RFaR expressed in Chinese hamster ovarian cells were also shown to activate intracellular protein kinase A signaling pathway upon cC-RFa₂₀ treatment (100 nM). Moreover, RT-PCR assay revealed that cPrRPR1, cPrRPR2, and cC-RFaR were widely expressed in most adult chicken tissues examined, including various regions of brain. These findings, together with evidence of PrRP and C-RFa encoded by separate genes in chicken, Xenopus, and zebrafish, and the differential expression of PrRP and C-RFa genes in chicken tissues, strongly suggest that PrRP and C-RFa may play similar yet distinctive roles in nonmammalian vertebrates, including chicken, and their actions are mediated by common receptor(s) or a specific C-RFa receptor.
促泌乳素释放肽（PrRP）及其结构相关肽，鲤鱼 Arg-Phe-酰胺肽（C-RFa），在脊椎动物中被报道具有相似的调节摄食和垂体功能的作用。然而，PrRP 和 C-RFa 的受体（s）的身份、功能和表达在包括鸟类在内的非哺乳动物脊椎动物中仍然知之甚少。在这项研究中，通过 RT-PCR 从鸡脑中克隆了三个与哺乳动物 PrRP 受体（PrRPR）同源的受体，分别命名为 cPrRPR1、cPrRPR2 和 cC-RFaR。使用 pGL3-NFAT-RE-荧光素酶报告系统，我们证明在中华仓鼠卵巢细胞中表达的 cPrRPR1 和 cPrRPR2 可以被 cPrRP₂₀ 和 cC-RFa₂₀ 强烈激活，而 cC-RFaR 只能被 cC-RFa₂₀（EC₅₀，0.11 nM）有效激活，表明 cPrRPR1 和 cPrRPR2 可以作为 PrRP 和 C-RFa 的共同受体，而 cC-RFaR 是 C-RFa 的特异性受体。使用 pGL3-CRE-荧光素酶报告系统，还表明在中华仓鼠卵巢细胞中表达的 cPrRPR1、cPrRPR2 和 cC-RFaR 在 cC-RFa₂₀（100 nM）处理后也能激活细胞内蛋白激酶 A 信号通路。此外，RT-PCR 检测显示 cPrRPR1、cPrRPR2 和 cC-RFaR 在大多数成年鸡组织中广泛表达，包括脑的不同区域。这些发现，加上鸡、非洲爪蟾和斑马鱼中分别由不同基因编码的 PrRP 和 C-RFa 的证据，以及鸡组织中 PrRP 和 C-RFa 基因的差异表达，强烈表明 PrRP 和 C-RFa 可能在包括鸡在内的非哺乳动物脊椎动物中发挥相似但又有区别的作用，它们的作用是由共同的受体或特定的 C-RFa 受体介导的。
