Lane 1, TDG addition (150 mM); Lane 2, cellobiose addition (150 mM); Lanes 3–5, TDG (150 mM) and GST-Gal1(WT) (10, 20, and 30 µM); Lanes 6–8, TDG (150 mM) and GST-Gal1( N46D) (10, 20, and 30 µM). Products of the splicing reactions were analyzed by electrophoresis through a 13% polyacrylamide-urea gel and autoradiography. The positions of migration of the pre-mRNA substrate, the splicing intermediates, and the mature RNA product are indicated on the right.