Inducible expression of (pp)pGpp synthetases in < i > Staphylococcus aureus < /i > is associated with activation of stress response genes

by Petra Horvatek, Andrea Salzer, Andrew Magdy Fekry Hanna, Fabio Lino Gratani, Daniela Keinh örster, Natalya Korn, Marina Borisova, Christoph Mayer, Dominik Rejman, Ulrike Mäder, Christiane Wolz The stringent response is characterized by the synthesis of the messenger molecules pppGpp, ppGpp or pGpp (here collectively designated (pp)pGpp). The phenotypic consequences resulting from (pp)pGpp accumulation vary among species and can be mediated by different underlying mechanisms. Most genome -wide analyses have been performed under stress conditions, which often mask the immediate effects of (pp)pGpp-mediated regulatory circuits. InStaphylococcus aureus, (pp)pGpp can be synthesized via the RelA-SpoT-homolog, RelSau upon amino acid limitation or via one of the two small (pp)pGpp synthetases RelP or RelQ upon cell wall stress. We used RNA-Seq to compare the global effects in response to induction of the synthetase ofrel-Syn (coding for the enzymatic region of RelSau) orrelQ without the need to apply additional stress conditions. Induction ofrel-Syn resulted in changes in the nucleotide pool similar to induction of the stringent response via the tRNA synthetase inhibitor mupirocin: a reduction in the GTP pool, an increase in the ATP pool and synthesis of pppGpp, ppGpp and pGpp. Induction of all three enzymes resulted in similar changes in the transcriptome. However, RelQ was less active than Rel-Syn and RelP, indicating strong restriction of its (pp)pGpp-synthesis activityin vi...
Source: PLoS Genetics - Category: Genetics & Stem Cells Authors: Source Type: research