(a) A template clone contains a TIIS DNA cassette (shaded in blue). Different tags such as GFP (green), Strep-tag II (red), and SNAPf (blue) contain the same two custom sticky ends that belong to SP and gene of interest (indicated by overhangs in black). TIIS restriction enzymes and T4 DNA ligase join them together in a universal manner.
(b) One sticky end on the right side of GFP is complementary to another one on the left side of Strep-tag II (indicated by green color bar). Similarly, Strep-tag II has a complementary sticky end to the one in SNAPf (indicated by red color bar). TIIS restriction enzyme and T4 ligase can fuse all those tags together and generate a multiple tandem tag (indicated by sequentially arranged GFP, Strep-tag II and SNAPf).