Catalyzes the transfer of galactose onto proteins or lipids. Required for susceptibility to pore-forming crystal toxins in conjunction with bre-1, bre-2, bre-3 and bre-5. Protein modification; protein glycosylation. Worms exhibit resistance to the Cry5B toxin produced by Bacillus thuringiensis. This is thought to be due to mutants having reduced population of glycolipids which are targeted by the Cry5B protein. Belongs to the glycosyltransferase 7 family.