UAS regulatory sequences (from pWalium10.moe) drive expression of an unanchored, uncleavable chain of six tandem copies of Ubiquitin; the chain lacks the internal "GG" motifs that are necessary for isopeptide bond formation and dismantling by deubiquitinases. The polyUbiquitin chain has a terminal "GG", meaning that it can potentially be conjugated onto other proteins; experiments in vivo show that this can occur in transgenic flies. The coding sequence is tagged at the N-terminal end with Tag:polyHis.