Screen for dosage suppressors of tgs1Δ cold sensitivity
tgs1∆ cells were transfected with a yeast genomic DNA library in vector YEp24 (2 μ URA3). Approximately 41,000 Ura+ transformants were plated on medium lacking uracil at 18°. The 2 μ plasmid was isolated from 20 colonies that grew at 18° and then transformed into Escherichia coli. Plasmids were prepared from cultures of individual ampicillin-resistant transformants. The 20 candidate suppressor plasmids were re-tested by transformation into the tgs1∆ strain; 16 of them rescued growth of tgs1∆ cells at 18°. Primers flanking the cloning site were used to sequence the ends of the genomic DNA inserts in these 16 plasmids and thereby identify the genes contained in each clone. Eight of the clones contained the TGS1 gene. Six plasmids contained a yeast genomic DNA locus, provisionally named DTS1 (DTS = deletion of TGS1 suppressor). Two plasmids contained a different yeast genomic locus, provisionally named DTS2.