title: Knockin mice expressing fluorescent delta-opioid receptors uncover G protein-coupled receptor dynamics in vivo.
abstract: The combination of fluorescent genetically encoded proteins with mouse engineering provides a fascinating means to study dynamic biological processes in mammals. At present, green fluorescent protein (GFP) mice were mainly developed to study gene expression patterns or cell morphology and migration. Here we used enhanced GFP (EGFP) to achieve functional imaging of a G protein-coupled receptor (GPCR) in vivo. We created mice where the delta-opioid receptor (DOR) is replaced by an active DOR-EGFP fusion. Confocal imaging revealed detailed receptor neuroanatomy throughout the nervous system of knock-in mice. Real-time imaging in primary neurons allowed dynamic visualization of drug-induced receptor trafficking. In DOR-EGFP animals, drug treatment triggered receptor endocytosis that correlated with the behavioral response. Mice with internalized receptors were insensitive to subsequent agonist administration, providing evidence that receptor sequestration limits drug efficacy in vivo. Direct receptor visualization in mice is a unique approach to receptor biology and drug design.
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM, Université Louis Pasteur, 1 Rue Laurent Fries, 67404 Illkirch, France.
authors.forename: Grégory
authors.initials: G
authors.lastname: Scherrer
authors.forename: Petra
authors.initials: P
authors.lastname: Tryoen-Tóth
authors.forename: Dominique
authors.initials: D
authors.lastname: Filliol
authors.forename: Audrey
authors.initials: A
authors.lastname: Matifas
authors.forename: Delphine
authors.initials: D
authors.lastname: Laustriat
authors.forename: Yu Q
authors.initials: YQ
authors.lastname: Cao
authors.forename: Allan I
authors.initials: AI
authors.lastname: Basbaum
authors.forename: Andrée
authors.initials: A
authors.lastname: Dierich
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Vonesh
authors.forename: Claire
authors.initials: C
authors.lastname: Gavériaux-Ruff
authors.forename: Brigitte L
authors.initials: BL
authors.lastname: Kieffer
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D004705:Endocytosis; D015870:Gene Expression; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D008822:Mice, Transgenic; D017465:Receptors, Opioid, delta / Q000235:genetics* / Q000378:metabolism*; D019076:Transgenes / Q000235:genetics
chemical_list: D017465:Receptors, Opioid, delta; D049452:Green Fluorescent Proteins