title: Constitutive Stringent Response Restores Viability of Bacillus subtilis Lacking Structural Maintenance of Chromosome Protein.
abstract: Bacillus subtilis mutants lacking the SMC-ScpAB complex are severely impaired for chromosome condensation and partitioning, DNA repair, and cells are not viable under standard laboratory conditions. We isolated suppressor mutations that restored the capacity of a smc deletion mutant (Δsmc) to grow under standard conditions. These suppressor mutations reduced chromosome segregation defects and abrogated hypersensitivity to gyrase inhibitors of Δsmc. Three suppressor mutations were mapped in genes involved in tRNA aminoacylation and maturation pathways. A transcriptomic survey of isolated suppressor mutations pointed to a potential link between suppression of Δsmc and induction of the stringent response. This link was confirmed by (p)ppGpp quantification which indicated a constitutive induction of the stringent response in multiple suppressor strains. Furthermore, sublethal concentrations of arginine hydroxamate (RHX), a potent inducer of stringent response, restored growth of Δsmc under non permissive conditions. We showed that production of (p)ppGpp alone was sufficient to suppress the thermosensitivity exhibited by the Δsmc mutant. Our findings shed new light on the coordination between chromosome dynamics mediated by SMC-ScpAB and other cellular processes during rapid bacterial growth.
authors.affiliation: INRA, UMR1319 Micalis, 78350, Jouy-en-Josas, France.|AgroParisTech, UMR Micalis 1319, 78350, Jouy-en-Josas, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Benoist
authors.affiliation: Mathématiques et Informatique Appliquées du Génome à l'Environnement, UR1404, INRA, Domaine de Vilvert, 78350, Jouy-en-Josas, France.
authors.forename: Cyprien
authors.initials: C
authors.lastname: Guérin
authors.affiliation: INRA, UMR1319 Micalis, 78350, Jouy-en-Josas, France.|AgroParisTech, UMR Micalis 1319, 78350, Jouy-en-Josas, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Noirot
authors.affiliation: INRA, UMR1319 Micalis, 78350, Jouy-en-Josas, France.|AgroParisTech, UMR Micalis 1319, 78350, Jouy-en-Josas, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Dervyn
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives / Q000235:genetics; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics; D020090:Chromosome Segregation / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D009154:Mutation / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D004269:DNA, Bacterial; C042715:argininehydroxamic acid; D012343:RNA, Transfer; D001120:Arginine