Fig. 4. ß-galactosidase filter assay of cells expressing Rer1p-Cub-PLV and the different Nub-fusion constructs. MML40 cells expressing Rer1p-Cub-PLV were transformed with plasmids carrying the different Nub-fusion proteins, as indicated on the left side of each panel. Four individual colonies were grown on Whatman III filter, permeabilized and incubated in the presence of X-Gal for two hours at 37°C, as described in the Materials and Methods. Expression of ß-galactosidase resulted in blue cells. Mns1p indicates cells expressing pRS314 Mns1p (lacking the Nub), and vector indicates cells expressing pRS314 as negative controls.