Cloning and Tissue Distribution of Novel Splice Variants of the Rat GABA Receptor

• Published in: Biochemical and biophysical research communications 1998-12, Vol.253 (1), p.10-15
• Main Authors: Isomoto, S, Kaibara, M, Sakurai-Yamashita, Y, Nagayama, Y, Uezono, Y, Yano, K, Taniyama, K
• Format: Article
• Language: English
• ISSN: 0006-291X
• DOI: 10.1006/bbrc.1998.9706

We have identified two novel splice variants of the metabotropic gamma -aminobutyric acid receptor (GABA sub(B)R1), designated GABA sub(B)R1c and GABA sub(B)R1d, when screening a rat cerebellum cDNA library. GABA sub(B)R1c has an amino acid sequence identical to GABA sub(B)R1b, a member of GABA sub(B)R1 isoforms, and an additional 93-bp insertion that generates an additional 31-amino-acid sequence in the fifth transmembrane region of GABA sub(B)R1b. Thus, GABA sub(B)R1c may have a structural variation in the second extracellular loop and fifth transmembrane region. GABA sub(B)R1d also has an amino acid sequence identical to GABA sub(B)R1b and an additional insertion of 566 bp that generates a divergent amino acid sequence in the carboxyl-terminal end. Reverse-transcription polymerase chain reaction analysis showed that in various rat tissues GABA sub(B)R1c mRNA was ubiquitously expressed and GABA sub(B)R1d mRNA in forebrain, cerebellum, eye, kidney, and urinary bladder. GABA sub(B)R1 isoforms may function not only in the central nervous system but also in various peripheral tissues.