Fig 2.

C. neoformans RHO1 is essential. KN99α and P_CTR4-RHO1, a strain with the endogenous RHO1 promoter replaced by a copper-repressible promoter, were grown overnight in YPD medium containing 200 μM BCS at 30°C and then diluted to an OD₆₅₀ of 1.0 in PBS. Five microliters of 10-fold serial dilutions were plated onto YPD plates containing either 200 μM BCS to allow expression of RHO1 from the copper promoter or 25 μM CuSO₄ to repress expression of RHO1 from this promoter. The ability of cells to grow was analyzed after 2 and 5 days (shown) at 30°C.