title: The dormancy regulator DosR controls ribosome stability in hypoxic mycobacteria.
abstract: It is thought that during latent infection, Mycobacterium tuberculosis bacilli are retained within granulomas in a low-oxygen environment. The dormancy survival (Dos) regulon, regulated by the response regulator DosR, appears to be essential for hypoxic survival in M. tuberculosis, but it is not known how the regulon promotes survival. Here we report that mycobacteria, in contrast to enteric bacteria, do not form higher-order structures (e.g. ribosomal dimers) upon entry into stasis. Instead, ribosomes are stabilized in the associated form (70S). Using a strategy incorporating microfluidic, proteomic, and ribosomal profiling techniques to elucidate the fate of mycobacterial ribosomes during hypoxic stasis, we show that the dormancy regulator DosR is required for optimal ribosome stabilization. We present evidence that the majority of this effect is mediated by the DosR-regulated protein MSMEG_3935 (a S30AE domain protein), which is associated with the ribosome under hypoxic conditions. A Δ3935 mutant phenocopies the ΔdosR mutant during hypoxia, and complementation of ΔdosR with the MSMEG_3935 gene leads to complete recovery of dosR mutant phenotypes during hypoxia. We suggest that this protein is named ribosome-associated factor under hypoxia (RafH) and that it is the major factor responsible for DosR-mediated hypoxic survival in mycobacteria.
authors.affiliation: Division of Cell and Molecular Biology, Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Andrej
authors.initials: A
authors.lastname: Trauner
authors.forename: Kathryn E A
authors.initials: KE
authors.lastname: Lougheed
authors.forename: Mark H
authors.initials: MH
authors.lastname: Bennett
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Hingley-Wilson
authors.forename: Huw D
authors.initials: HD
authors.lastname: Williams
mesh_terms: D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D050296:Microbial Viability / Q000235:genetics; D009154:Mutation; D020102:Mycobacterium smegmatis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D020871:RNA Stability; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D018085:Regulon / Q000235:genetics*; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C542863:DosR protein, Mycobacterium tuberculosis; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; D011494:Protein Kinases