In contrast, the triple mutant fucA1 tm produced in E.coli only the low molecular weight band resulting from translational termination ( Figure 4D ). No full-length protein could be detected in western blots probed with either anti-GST ( Figure 4D ) or anti-Ssa-fuc antibodies ( Figure 4E ). These data show that the disruption of the heptameric slippery sequence completely abolished the frameshifting in E.coli confirming that this sequence has a direct role in controlling the frameshifting in vivo.