Abstract:The complete cDNA sequences of two distinct somatostatin receptor genes (SSTR2 and SSTR3) were isolated from Siniperca chuatsi brain and cloned by means of rapid amplification of cDNA ends (RACE).The full length of SSTR2 cDNA was 1820 bp,containing 1146 bp open reading frame and encoding 382 amino acids,whereas the full length of SSTR3 cDNA was 1874 bp,containing 1458 bp open reading frame and encoding 486 amino acids.Five domains were detected in SSTRs: the N-terminal domain,seven putative transmembrane domains (TMD),three extracellular loops (ECLs),four intracellular loops (ICLs) and the C-terminal domain.NJ phylogenetic tree showed that SSTR2 and SSTR3 formed two independent branches,and that the amino acid sequence similarity between SSTR2 and SSTR3 was 51.2%,which indicated that they were encoded by two different genes.A wide tissue expression of SSTR2 and SSTR3 mRNA were revealed by real-time quantitative RT-PCR,with the highest expression of SSTR2 mRNA in liver,and SSTR3 mRNA in stomach,suggesting that they may be involved in different physiological regulations.