Figure 3. Complementation of yeast COQ2 null mutant by yeast and human COQ2 genes.

(A) Null mutant strain CENΔCoq2 (•) and the same yeast strain harbouring vectors containing human (▵) or yeast (□) COQ2 from two isolated clones were grown overnight in 15 ml of YPD and SD-ura respectively. The cultures were diluted into 50 ml YPG (A₆₀₀=0.1). Growth was monitored by A₆₀₀ measurements. Open and closed symbols represent measurement of two independent clones except for the control null mutant strain CENΔCoq2, which is one clone (A₆₀₀=0.003–0.05). (B) Effect of N-terminal sequence deletions of the human COQ2 gene. Ctrl-1, null mutant strain CENΔCoq2; Ctrl-2 and Ctrl-3, yeast harbouring control plasmids. Cells were grown in YPD and SD-ura. A spot test for growth was performed by dropping 2.5 μl of each culture on to YPG agar plates and incubating at 30 °C for 5 days. Two independent spots were applied.