QUAS regulatory sequences drive expression of 'pre-mGRASP' tagged at the C-terminal end with 2xTag:HA followed by sequence encoding 219 amino acid residues of the Rab3 gene. pre-mGRASP (PMID:22138823) is composed of an N-terminal signal peptide, the spGFP11 split fluorescent protein fragment, the extracellular and transmembrane domains of the human CD4 gene and an intracellular domain that targets the protein to presynaptic sites (Tag:TS(rNrxn1-β)).