Figure 7.

(A) A grr1Δ mutation blocks full induction of CIT2 expression. Wild-type and grr1Δ cells were grown in rich YPD or minimal YNBD medium to midlog phase. Total mRNA was prepared and CIT2 mRNA levels were determined by Northern blot analysis. ACT1 was used as loading control. (B) A grr1Δ mutation blocks ubiquitination of Mks1p expressed from its own promoter. Ubiquitination of Mks1p was determined as described in Figure 3F. (C) The grr1Δ and rtg2Δ mutations additively reduce cell growth on medium lacking glutamate. Serial dilutions (5×) of cultures were prepared and cells were spotted onto solid YNBD medium with or without 0.02% glutamate. Cells were grown for 3-4 d at 30°C.