Knockin mice expressing fluorescent delta-opioid receptors uncover G protein-coupled receptor dynamics in vivo.
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.
Scherrer
Grégory
G
Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM, Université Louis Pasteur, 1 Rue Laurent Fries, 67404 Illkirch, France.
Tryoen-Tóth
Petra
P
Filliol
Dominique
D
Matifas
Audrey
A
Laustriat
Delphine
D
Cao
Yu Q
YQ
Basbaum
Allan I
AI
Dierich
Andrée
A
Vonesh
Jean-Luc
JL
Gavériaux-Ruff
Claire
C
Kieffer
Brigitte L
BL
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
D017465:Receptors, Opioid, delta; D049452:Green Fluorescent Proteins