Figure 8.

Stabilization of a ubiquitin fusion degradation pathway substrate in daq1Δ cells. Wild-type DAQ1 and daq1Δ mutant cells were transformed with a reporter plasmid expressing the Ub^V76-Val-e^ΔK-βgal fusion protein. Metabolic stability of the proteasome reporter substrate in the two strains was monitored by pulse-chase analysis as described in MATERIALS AND METHODS. (A) SDS-PAGE gel analysis of the ³⁵S-labeled substrate protein (arrow). The bracket indicates the ubiquitinated forms of βgal reporter protein and the asterisk the position of the 90-kDa stable breakdown product of the reporter protein. (B). Quantitative analysis. The intensities of the βgal reporter protein bands in A were determined by PhosphorImager analysis and plotted as a funtion of time.