20XUAS regulatory sequences drive expression of the Gba1b coding sequence (minigene comprised of exons 1-9 including signal sequence, omitting introns and UTRs), mutated to carry a E404K amino acid replacement (this change is equivalent to a E340K change in the orthologous human gene and results in a catalytically inactive protein). Sequence containing a NotI site, a 6xGly linker and a Tag:V5 tag have been inserted at the C-terminal end of the open reading frame; a cloning error resulted in a frameshift after the NotI linker, rendering the Tag:V5 tag unusable.