A mouse model for visualization of GABA_B receptors

Abstract

GABA(B) receptors are the G-protein-coupled receptors for the neurotransmitter gamma-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.

GABA suppresses neurogenesis in the adult hippocampus through GABAB receptors

“…, GABA GFAP::CreER T2 , mR26CS-EGFP and Hes5::GFP mice have been described elsewhere (Schuler et al, 2001;Gassmann et al, 2004;Haller et al, 2004;Hirrlinger et al, 2006;Vigot et al, 2006;Casanova et al, 2009;Lugert et al, 2010;Tchorz et al, 2012). Mice were maintained on a 12-hour day/night cycle with adequate food and water under specific-pathogen-free (SPF) conditions according to institutional regulations and under license numbers Germany) and 2537 and 2538 (Kantonales Veterinäramt, Basel).…”

“…We analyzed mice expressing functional GABA B1 -GFP fusion proteins under the control of GABA B1 regulatory elements (Fig. 1I) (Casanova et al, 2009). GABA B1 -GFP colocalized with the neuroblast marker polysialylated neural cell adhesion molecule and brain lipid binding protein in progenitor cells (Fig.…”

Transport along the dendritic endoplasmic reticulum defines the trafficking modality for GABAB receptors

“…1F). To rule out the possibility of artificial colocalization due to overexpression, we analyzed neurons derived from GABA B1 -EGFP transgenic mice, which express GABA B1 -EGFP at endogenous levels (Casanova et al, 2009). Colocalization between GABA B1 and the ER in this model was comparable to that observed with overexpressed subunits (Fig.…”

“…They carry a bacterial artificial chromosome containing GABA B1 -EGFP in a homozygous knockout background for GABA B1 . The construct is expressed under control of GABA B1 promoter elements (Schuler et al, 2001;Casanova et al, 2009). …”

Analysis of the in-vivo GABAB receptor relocalization and oligomerization in chronic pain conditions using spatial intensity distribution analysis

“…A total number of ten transgenic mice expressing GABA B1 receptor-subunits fused to eGFP were sacrificed [10]. Among these, persistent neuropathic and inflammatory pain was evoked in two mice with Spared Nerve Injury (SNI), two mice were injected with Complete Freund's Adjuvant (CFA), two mice were injected with NaCl for sham conditons, four mice were left untreated.…”