UASt regulatory sequences drive expression of two tandem copies of the VHH(dGBP1) nanobody (separated by a 15 amino acid linker), tagged at the C-terminal end (via a 25 amino acid linker) with TurboID (tag is codon optimized for expression in Drosophila). Although the VHH(dGBP1) nanobody was expected to be unstable in the absence of antigen (PMID:27205882), the VHH(dGBP1)-TurboID fusion protein produced is not degraded in the absence of antigen (such as GFP).