Reyes-Ruiz Jorge Mauricio, Limon Agenor, Miledi Ricardo
Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.
Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.
Neurosci Lett. 2014 Jan 13;558:78-81. doi: 10.1016/j.neulet.2013.11.003. Epub 2013 Nov 14.
Since human and pig eyes have remarkably anatomical and physiological similitudes swine models have been broadly used for functional studies and therapeutic research. Recently, a GABAρ-mediated relaxation of retinal vascularity suggested that GABAρ signaling may be used to improve retinal blood flow in vascular-driven impaired vision, and a further molecular characterization of GABAρ receptors would be beneficial. However, none of the GABAρ type subunits from pigs has been yet cloned; Among the 19 subunits that compose the family of GABAA receptors, ρ1-3 subunits are capable of forming homomeric channels. These homomeric receptors are particularly interesting because their pharmacological and kinetic properties are notably different from receptors composed by other GABAA subunits. Here we report the cloning of the GABAρ1subunit from the pig and the functional expression of homomeric channels in Xenopus oocytes. The most notable difference found in the pig GABAρ1 receptor was the absence of a stretch of 17 amino acids near the amino terminus (R41-V58) conserved in the rat and the human. This sequence has a higher nucleotidic match with the transcript variant 2 of the human GABAρ1 subunit. Xenopus oocytes injected with cRNA from the receptor generated currents when exposed to GABA that shared all the characteristics of other GABAρ1 subunits in mammals, including its modulation by dopamine. This study will help to increase the knowledge of the genetics of the pig, further the understanding of this important neurotransmitter receptor family and will shed some light in the evolution of these genes among mammals.
由于人类和猪的眼睛在解剖学和生理学上有显著的相似性，猪模型已被广泛用于功能研究和治疗研究。最近，一种由GABAρ介导的视网膜血管舒张表明，GABAρ信号传导可用于改善血管驱动性视力受损中的视网膜血流，对GABAρ受体进行进一步的分子特征分析将是有益的。然而，猪的GABAρ型亚基尚未被克隆；在构成GABAA受体家族的19个亚基中，ρ1-3亚基能够形成同聚体通道。这些同聚体受体特别有趣，因为它们的药理学和动力学特性与由其他GABAA亚基组成的受体明显不同。在此，我们报告了猪GABAρ1亚基的克隆以及同聚体通道在非洲爪蟾卵母细胞中的功能表达。在猪GABAρ1受体中发现的最显著差异是在氨基末端附近缺少一段在大鼠和人类中保守的17个氨基酸序列（R41-V58）。该序列与人类GABAρ1亚基的转录变体2具有更高的核苷酸匹配度。当暴露于GABA时，注射了该受体cRNA的非洲爪蟾卵母细胞产生电流，这些电流具有哺乳动物中其他GABAρ亚基的所有特征，包括其受多巴胺调节。这项研究将有助于增加对猪遗传学的了解，进一步加深对这个重要神经递质受体家族的理解，并将为这些基因在哺乳动物中的进化提供一些线索。
