A mouse model for visualization of GABA_Breceptors

Abstract GABA B receptors are the G‐protein‐coupled receptors for the neurotransmitter γ‐aminobutyric acid (GABA). Receptor subtypes are based on the subunit isoforms GABA B1a and GABA B1b , which combine with GABA B2 subunits to form heteromeric receptors. Here, we used a modified bacterial artificial chromosome (BAC) containing the GABA B1 gene to generate transgenic mice expressing GABA B1a and GABA B1b subunits fused to the enhanced green fluorescence protein (eGFP). We demonstrate that the GABA B1 ‐eGFP fusion proteins reproduce the cellular expression patterns of endogenous GABA B1 proteins in the brain and in peripheral tissue. Crossing the GABA B1 ‐eGFP BAC transgene into the GABA B1 −/− background restores pre and postsynaptic GABA B functions, showing that the GABA B1 ‐eGFP fusion proteins substitute for the lack of endogenous GABA B1 proteins. Finally, we demonstrate that the GABA B1 ‐eGFP fusion proteins replicate the temporal expression patterns of native GABA B receptors in cultured neurons. These transgenic mice therefore provide a validated tool for direct visualization of native GABA B receptors. genesis 47:595–602, 2009. © 2009 Wiley‐Liss, Inc.