Generation of R40C-W. The yeast strain R40C (coat) (24) was disrupted in TRP1 gene in order to obtain tryptophane auxotrophy required for transformation with the pYESTrp1 vector. The disruption cassette was constructed in the YDp-W (25) vector by cloning KanMX resistance marker from pFA6akanMX4 (26) into XbaI-HindIII sites (blunted) within TRP1 gene. R40C was transformed with BamHI-BamHI fragment containing the disruption cassette and selected on geneticin (G418, 200 mg/ml) -containing medium.