The endogenous VGlut1 locus has been modified so that sequence encoding 40 tandem copies of Tag:MYC have been inserted at the C-terminal end of the coding sequence. In addition, an B2RT-flanked transcription stop cassette has been inserted in the intron in between exons 6 and 7; this intron is within the coding sequence and the presence of the stop cassette is predicted to result in a conditional loss of function allele.