孤儿G蛋白偶联受体hGPCRc的亚细胞定位及组织分布

利用相关生物信息学软件,对从人结肠组织克隆所得某一孤儿G蛋白偶联受体(orphanGprotein_coupledreceptors ,oGPCRs)成员hGPCRc的氨基酸序列进行分析显示,hGPCRc对应的氨基酸序列组成了七个跨膜区段的结构域,具备GPCR的结构特征;然后,将hGPCRc之cDNA与绿色荧光载体pEGFP-N₁ 构建GFP_hGPCRc表达载体,以空白质粒pEGFP-N₁ 作对照,转染CHO-K₁ 细胞,在激光扫描共聚焦显微镜下观察到空白质粒pEGFP-N₁ 转染的细胞表达了GFP并均匀分布于整个细胞,而GFP_hGPCRc转染的细胞观察到荧光清晰聚集于细胞膜和各细胞器质膜上,因而hGPCRc蛋白定位于膜上并稳定表达,与软件分析结果相一致;最后,以RT_PCR检测hGPCRc在2 0周龄胎儿重要组织器官及部分成人组织中的表达情况,结果显示hGPCRc在人心、肾、小脑及结肠等组织均有表达,但在肝、大脑、小肠及肌肉等组织里未检测到表达。该表达谱对于进一步认识hGPCRc在胚胎发育中的作用及生理功能提供了线索。

Subcellular Localization and Tissues Expression Profile of hGPCRc: an Orphan G Protein-Coupled Receptor

As a member of orphan G protein-coupled receptors (oGPCRs), hGPCRc was cloned from human colon tissue and analyzed by bioinformatic softwares. It was showed that the corresponding amino acids of hGPCRc formed seven-transmembrane domains as the key characteristic of GPCRs. Then, the recombinant GFP-hGPCRc was constructed by fussing hGPCRc into pEGFP-N 1 carrying green fluorescent protein (GFP) gene, and CHO-K 1 cells were subsequently transfected with the GFP-hGPCRc or pEGFP-N 1. The green fluorescence protein expression in the two different transfected cells was observed under the laser scanning confocal microscopy (LSCM). It was showed that green fluorescence protein was distributed in the whole bodies of the cells transfected with pEGFP-N 1, but mainly distributed on the plasma membrane and cytoplasm membrane transfected with GFP-hGPCRc. Thus, the localization on the membrane of hGPCRc was accorded with the predication by bioinformatic analysis. The expression analysis of hGPCRc by RT-PCR indicated that hGPCRc was abundantly expressed in heart, kidney, cerebel and colon etc., but absent in liver, cerebra, small intestine and muscle etc.. The expressing profile of hGPCRc could provide some useful clues to understanding its effects on embryonic development and physiological functions.