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. Author manuscript; available in PMC: 2021 Aug 26.
Published in final edited form as: Cell Syst. 2020 Jul 28;11(2):121–130.e6. doi: 10.1016/j.cels.2020.07.005

Figure 4. Removal of the stringent response negatively impacts cell growth during aaRS underproduction.

Figure 4.

(A) Induction of CodY-controlled amino acid biosynthetic genes as a proxy for stringent response activation across aaRS expression. RNA-seq was performed on strains producing IleS and ArgS over a range of induction conditions. The fold change in transcriptome fraction (RPKM) for genes related to amino acid metabolism was compared to wildtype. See Table S1 for list of genes. aaRS production was calibrated in the same way as Figure 1C. (B) Potential models for aaRS fitness landscape for cells lacking the stringent response. The stringent response may amplify the effects of insufficient tRNA charging (Regulation detrimental), or reduce adverse effects (Regulation beneficial). (C) Effects on aaRS fitness landscape of stringent response removal. Strains with stringent response intact (circles) were competed against stringent null cells (squares) across the aaRS production landscape. Measurements of fitness and aaRS production were calculated as in Figure 1. See also Figure S4.