UASt regulates expression of Hsap\SGMS1 with a point mutation in the conserved catalytic domain - it has an abolished D3 (C-G-D-X3-S-G-H-T) motif, with S-G-H mutated to A-G-A, where histidine H constitutes part of the structural HHD motif critical for the catalytic function. It has a C-terminal Tag:V5 tag.