• Somatostatin Receptor 2 (SSTR2) is one of five 7-transmembrane G-protein-coupled receptors for somatostatins 14 and 28. Human SSTR2 shares 84% aa identity with mouse SSTR2 within the extracellular domains. Isoform B (357 aa) has an alternate C-terminal cytoplasmic region that is 12 aa shorter than that of isoform A (369 aa, reported as 93 kDa). Both are expressed in brain, stomach, intestinal epithelia, pancreatic islets and kidney tubules. Isoform B is also expressed in parotid, thyroid and bronchial glands.
• The exon 2 of mouse Sstr2 gene that encode the extracellular and transmembrane domains was replaced by human SSTR2 exon 2 in B-hSSTR2 mice. 
• Mouse Sstr2 mRNA was detectable in cerebellum of wild-type C57BL/6 mice. Human SSTR2 mRNA was detectable in homozygous B-hSSTR2 mice. 
• Human SSTR2 was detectable in cerebellum, pancreas, stomach, esophagus and uterus of homozygous B-hSSTR2 mice. 
• Application: This product is used for the efficacy evaluation and safety evaluation of drugs for the treatment of neuroendocrine tumors.

Strain specific analysis of SSTR2 mRNA expression in wild-type C57BL/6 mice and B-hSSTR2 mice by RT-PCR. Cerebellum RNA were isolated from wildtype C57BL/6 mice (+/+) and homozygous B-hSSTR2 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human SSTR2 primers. Mouse Sstr2 mRNA was only detectable in wild-type C57BL/6 mice. Human SSTR2 mRNA was only detectable in homozygous B-hSSTR2 mice. 

Protein expression analysis

Western blot analysis of SSTR2 protein expression in homozygous B-hSSTR2 mice. Various tissue lysates were collected from wild-type C57BL/6N (+/+) mice and homozygous B-hSSTR2 mice (H/H), and then analyzed by western blot with anti-SSTR2 antibody. 40 μg total proteins were loaded for western blotting analysis. SSTR2 was detected in cerebellum, pancreas, stomach, esophagus, uterus and colon.

References using B-hTSLP mice

1. Oberg KE, Reubi JC, Kwekkeboom DJ, Krenning EP. Role of somatostatins in gastroenteropancreatic neuroendocrine tumor development and therapy. Gastroenterology. 2010 Sep;139(3):742-53, 753.e1. 
2. Eychenne R, Bouvry C, Bourgeois M, Loyer P, Benoist E, Lepareur N. Overview of Radiolabeled Somatostatin Analogs for Cancer Imaging and Therapy. Molecules. 2020 Sep 2;25(17):4012.