Figure 7.

Rare [PSI+] variant sensitive to curing by Cur1p overproduction. In strain 74D-694 carrying pBEE2 (CEN LEU2 GAL1promoter-CUR1) and pSL1066 (CEN URA3 CUP1promoter-SUP35NM-GFP) [PSI+] variants were copper-induced. Cur1-sensitive colonies were found by subcloning on galactose media and picking those which became [psi-]. The original [PSI+] Cur1-sensitive variants were streaked on YPAD plates to allow loss of pBEE2 and pSL1066, were retransformed with pBEE2 or empty vector control (pH316) and tested for Cur1-sensitivity again by streaking cells on selective plates containing 2% galactose and 10 mg/l adenine. The galactose plates were replica plated to dextrose plates lacking adenine (below).