Identification and cloning of three novel human G protein-coupled receptor genes GPR52, ΨGPR53 and GPR55: GPR55 is extensively expressed in human brain

• Published in: Brain research. Molecular brain research. 1999-02, Vol.64 (2), p.193-198
• Main Authors: Sawzdargo, Marek, Nguyen, Tuan, Lee, Dennis K, Lynch, Kevin R, Cheng, Regina, Heng, Henry H.Q, George, Susan R, O'Dowd, Brian F
• Format: Article
• Language: English
• Subjects: Biochemistry and metabolism; Biological and medical sciences; Central nervous system; Chromosome; Fundamental and applied biological sciences. Psychology; GPCR; Intronless; Northern blot; Pseudogene; Receptor; Vertebrates: nervous system and sense organs
• ISSN: 0169-328X; 1872-6941
• 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 ΨGPR53. GPR55 was identified from the expressed sequence tags (EST) database whereas GPR52 and pseudogene ΨGPR53 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 ΨGPR53 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. ΨGPR53 is a pseudogene mapped to chromosome 6p21 that demonstrates the highest similarity to the MRG (35%), MAS (28%) and C5a (24%) human receptor genes.