The cph2 upc2 double mutant is completely defective in hypoxic growth. WT (HLY4151), cph2 (HLY4152), cph2+CPH2 (HLY4195), upc2 (54), and two independently obtained cph2 upc2 double mutant strains (HLY4007 and HLY4008) were grown in YPD to an OD600 of ∼1. Cells were diluted to an OD600 of 0.1 and then serially diluted 5-fold, spotted (1.25 μl) onto YPD and SC plates, and grown at 37°C in normoxia or 0.2% O2 and 5% CO2 for a day before pictures were taken.