Western blot of Urm1 fusion protein. Anti- Urm1 antibody generated by immunization with recombinant yeast Urm1 was tested by western blot against yeast lysates expressing the Urm1-GFP fusion protein and other UBL fusion proteins. All UBLs possess limited homology to Ubiquitin and to each other, therefore it is important to know the degree of reactivity of each antibody against each UBL. Panel A shows total protein staining using ponceau. Panel B shows positions of free GFP or GFP containing recombinant proteins present in each lysate preparation after reaction with a 1:1,000 dilution of GeneTex's anti-GFP