Yeast Strains and Growth Conditions

trp12D63, leu2 D, ura3-52) [S1]. The tpkw strains were gifts from J. Broach. The strains YNP2 and PSY1201 were gifts from P. Silver. All of the cultures were performed at 30C in YNBmedium supple-mented by the required amino acids. Plasmid Constructions In all of the constructions, we used pAMG as a template [S2], and the sequences of oligonucleotides we used are shown in Table S1. An intermediary plasmid called pO1wasmade in order to facilitate further constructions. This plasmid is derived from pAMG and con-tains the ATG, a small polylinker (SalI, BamHI, and PstI), and the sequence of MSN2 from 1723 to the end and the sequence of GFP. The MSN2-GFP open reading frame (ORF), cut out by SalI and HindIII, has been replaced by the SalI-HindIII-cut polymerase chain reaction (PCR) fragment obtained by oligonucleotides ol1 up and olGFPh