A Ubiquitin promoter drives expression of the mGluR coding sequence that is tagged at the N-terminal end with Tag:FLAG and at the C-terminal end with 3xVHH05-tag. The codon usage of the mGluR coding sequence has been modified (by synonymous codon substitutions) so that all of the codons correspond to the most commonly used synonymous codon in the D. melanogaster genome (these substitutions also remove all annotated orb2 binding sites in the mRNA).