Receptor knock-out and knock-in strategies.
Accumulating examples have demonstrated that knock-out and knock-in mice of G-protein-coupled receptors (GPCRs) are useful in elucidating physiological functions of the receptor in vivo. GPCR knock-out and knock-in are achieved by either (1) manipulation of the endogenous locus of the receptor gene or (2) transgenic expression of the modified receptor. Historically speaking, the first generation knock-outs made the best use of homologous recombination in embryonic stem (ES) cells and their totipotency to introduce the desired mutation into the endogenous receptor locus. In the second-generation knock-outs using the Cre/loxP system, the disruption of the receptor gene is cell-type specific or region-specific but is irreversible in principle. In contrast, transgenic expression in the receptor knock-out mice of the wild-type receptor protein under a tissue- and stage-specific promoter (conditional "rescue" of the receptor knock-out) can be easily applied to create "reversible" or "inducible" knock-out of the receptor. This is called the third generation knock-out. In the following sections, we introduce examples of the materials and methods based on our in vivo analyses of the metabotropic glutamate receptor-subtype 1 (mGluR1).
Matsuda
Ikuo
I
Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Japan.
Aiba
Atsu
A
D000818:Animals; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering / Q000379:methods*; D019426:Integrases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D011401:Promoter Regions, Genetic; D008249:Protein-Lysine 6-Oxidase / Q000235:genetics / Q000378:metabolism; D011689:Purkinje Cells; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000378:metabolism; D019076:Transgenes; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
D016326:Extracellular Matrix Proteins; D043562:Receptors, G-Protein-Coupled; D018094:Receptors, Metabotropic Glutamate; D014764:Viral Proteins; C104077:metabotropic glutamate receptor type 1; C077112:Lox protein, mouse; D008249:Protein-Lysine 6-Oxidase; C045073:Cre recombinase; D019426:Integrases