Sawzdargo M, Nguyen T, Lee D K, Lynch K R, Cheng R, Heng H H, George S R, O'Dowd B F
Department of Pharmacology, University of Toronto, Medical Sciences Building, Toronto, Ontario, Canada, USA.
Brain Res Mol Brain Res. 1999 Feb 5;64(2):193-8. doi: 10.1016/s0169-328x(98)00277-0.
The G protein-coupled receptor (GPCR) family share a structural motif of seven transmembrane segments with large numbers of conserved residues in those regions. Here, we report the identification and cloning of two novel human intronless GPCR genes, GPR52, GPR55 and a pseudogene PsiGPR53. GPR55 was identified from the expressed sequence tags (EST) database whereas GPR52 and pseudogene PsiGPR53 originated from the high throughput genome (HTG) database. A partial cDNA clone obtained from the IMAGE Consortium of GPR55 was used to screen a human genomic library to acquire the full length gene. GPR52 and PsiGPR53 were amplified from human genomic DNA using primers based on the HTG sequences. GPR55 and GPR52 encode receptors of 319 and 361 amino acids, respectively. GPR55 gene was mapped to chromosome 2q37, using fluorescence in situ hybridization (FISH), and its mRNA transcripts have been detected in the caudate nucleus and putamen, but not in five other brain regions. Human receptors showing the highest amino acid identity to GPR55 include P2Y5 (29%), GPR23 (30%), GPR35 (27%) and CCR4 (23%). GPR52 gene localized to chromosome 1q24 shares the highest identity with GPR21 (71%), histamine H2 (27%) and 5-HT4 (26%) human receptors. PsiGPR53 is a pseudogene mapped to chromosome 6p21 that demonstrates the highest similarity to the MRG (35%), MAS (28%) and C5a (24%) human receptor genes.
G蛋白偶联受体（GPCR）家族具有七个跨膜区段的结构基序，这些区域有大量保守残基。在此，我们报告两个新的人类无内含子GPCR基因GPR52、GPR55和一个假基因PsiGPR53的鉴定与克隆。GPR55是从表达序列标签（EST）数据库中鉴定出来的，而GPR52和假基因PsiGPR53则源自高通量基因组（HTG）数据库。从GPR55的IMAGE联合体获得的部分cDNA克隆用于筛选人类基因组文库以获取全长基因。基于HTG序列设计引物，从人类基因组DNA中扩增出GPR52和PsiGPR53。GPR55和GPR52分别编码319和361个氨基酸的受体。利用荧光原位杂交（FISH）技术将GPR55基因定位到染色体2q37，并且在尾状核和壳核中检测到了它的mRNA转录本，但在其他五个脑区中未检测到。与GPR55氨基酸同一性最高的人类受体包括P2Y5（29%）﹑GPR23（30%）﹑GPR35（27%）和CCR4（23%）。定位于染色体1q24的GPR52基因与GPR21（71%）、组胺H₂（27%）和5-HT4（26%）人类受体具有最高的同一性。PsiGPR53是一个定位到染色体6p21的假基因，与MRG（35%）、MAS（28%）和C5a（24%）人类受体基因具有最高的相似性。
