A Genome-Wide Screen for Regulators of TORC1 in Response to Amino Acid Starvation Reveals a Conserved Npr2/3 Complex
Figure 4
npr2Δ and npr3Δ cells fail to repress RP gene expression when grown in a non-preferred nitrogen source.
(A) Gene expression profile of WT and npr2Δ cells shifted from YPD to N-free media. For each gene, a fold change in expression from YPD media to 30 minutes in N-free media is plotted. This ratio for WT cells is plotted in the X-axis and the same ratio for npr2Δ is plotted in the Y-axis. Identical results were obtained with npr3Δ. The expression of large and small ribosomal protein genes, RPL and RPS, respectively, is in shown in red. (B) Relative level of RP gene expression with respect to WT. The expression of each RP mRNA in npr2Δ and npr3Δ cells was compared to the level of its expression in WT cells and the average ratio is shown. Note the higher expression of RP genes in npr2Δ and npr3Δ cells in N-free media and similar expression in YPD media. (C) Quantitative RT-PCR of RPL and RPS mRNA. Total RNA was isolated from WT, npr2Δ and npr3Δ cells grown in either YPD or N-free media and the expression was determined by RT-PCR. Each mRNA was quantitated with respect to WT cells grown in N-free media. (D) Quantitative RT-PCR was performed on cells grown in N-free media supplemented 10 mM proline, 10 mM glutamine or 2% peptone. Each mRNA was quantitated with respect to WT cells grown in 10 mM glutamine media. (E) Quantitative RT-PCR was performed on cells grown in N-free media supplemented with 0, 1 or 50 mM ammonium sulfate. Each mRNA was quantitated with respect to WT cells grown in 50 mM ammonium sulfate.