In a first aspect the present invention provides an inducible
expression vector encoding a
metabotropic glutamate receptor. In particular a
tetracycline inducible
expression vector such as for example the commercially available pcDNA4 / TO
mammalian expression vector (Invitrogen, Carlsbad, Calif. USA) comprising the
nucleotide sequence encoding for a member of the Group I mGluRs, in particular for the human mGluR1a (SEQ ID No1) or mGluR5
receptor (SEQ ID No.3). In a more preferred embodiment the inducible
expression vector is selected from the
tetracycline inducible expression plasmids hmGlu1a-pcDNA4 / TO (FIG. 4) and hmGlu5a-pcDNA4 / TO (FIG. 5). In a second aspect, the present invention provides a
cell line comprising any of the aforementioned inducible expression vectors. In particular the T-Rex-293 cells stably transfected with the
tetracycline inducible expression plasmids hmGlu1a-pcDNA4 / TO (FIG. 4) and hmGlu5a-pcDNA4 / TO (FIG. 5) which where deposited at the Belgian Coordinated Collections of Microorganisms (BCCM) as T-Rex-293-hmGlu1a-pcDNA4 / TO clone on Jun. 24, 2004. In a third aspect the present invention provides a method to identify compounds capability to modulate the activity of a
metabotropic glutamate receptor said method comprising the steps of; contacting the aforementioned
cell line with the compound to be tested, and determining the effect of said test compound on the
metabotropic glutamate receptor activity. The effect on the metabotropic
glutamate receptor activity is typically determined by assessing the change in
intracellular calcium, in particular using a fluorescent dye such as for example fluo-3-AM. It is also an object of the present invention to provide a method to identify a compound capable to interact with a metabotrobic
glutamate receptor, in particular with a Group I mGluR
receptor, said method comprising the steps of contacting the cells according to the invention with the compounds to be tested under appropriate conditions and determining the binding of said test compounds to the cells.