mRNA distribution of two isoforms of somatostatin receptor 2 (mSSTR2A and mSSTR2B) in mouse brain.
The primary gene transcript of the mouse somatostatin receptor 2 is alternatively spliced giving rise to two isoforms (mSSTR2A and mSSTR2B) which differ at the C-terminus. Using reverse transcription polymerase chain reaction (RT-PCR), both mRNAs were found in the cortex, hippocampus, hypothalamus, striatum, mesencephalon, cerebellum, medulla oblongata, pituitary and in testis, however with different ratios between mSSTR2A and mSSTR2B, implicating a tissue-specific control of transcription and splicing. Among the analyzed tissues, cortex contained the highest amounts of mSSTR2A but only little mSSTR2B, whereas the pons/medulla oblongata expressed both isoforms to an equal extent. Northern blot analysis of these tissues revealed a single mRNA of about 2.4 kb using a mSSTR2A-specific hybridization probe. No additional signal was seen using a probe which hybridizes to both mSSTR2A and mSSTR2B, suggesting that the two mRNAs may be nearly identical in length. In addition, in situ hybridization indicated that mSSTR2A is predominantly expressed in mouse brain, and mSSTR2B is never expressed independently from mSSTR2A.