title: Integrated transcriptomic and proteomic analysis of the global response of Wolbachia to doxycycline-induced stress.
abstract: The bacterium Wolbachia (order Rickettsiales), representing perhaps the most abundant vertically transmitted microbe worldwide, infects arthropods and filarial nematodes. In arthropods, Wolbachia can induce reproductive alterations and interfere with the transmission of several arthropod-borne pathogens. In addition, Wolbachia is an obligate mutualist of the filarial parasites that cause lymphatic filariasis and onchocerciasis in the tropics. Targeting Wolbachia with tetracycline antibiotics leads to sterilisation and ultimately death of adult filariae. However, several weeks of treatment are required, restricting the implementation of this control strategy. To date, the response of Wolbachia to stress has not been investigated, and almost nothing is known about global regulation of gene expression in this organism. We exposed an arthropod Wolbachia strain to doxycycline in vitro, and analysed differential expression by directional RNA-seq and label-free, quantitative proteomics. We found that Wolbachia responded not only by modulating expression of the translation machinery, but also by upregulating nucleotide synthesis and energy metabolism, while downregulating outer membrane proteins. Moreover, Wolbachia increased the expression of a key component of the twin-arginine translocase (tatA) and a phosphate ABC transporter ATPase (PstB); the latter is associated with decreased susceptibility to antimicrobials in free-living bacteria. Finally, the downregulation of 6S RNA during translational inhibition suggests that this small RNA is involved in growth rate control. Despite its highly reduced genome, Wolbachia shows a surprising ability to regulate gene expression during exposure to a potent stressor. Our findings have general relevance for the chemotherapy of obligate intracellular bacteria and the mechanistic basis of persistence in the Rickettsiales.
authors.affiliation: Institute of Integrative Biology and the Centre for Genomic Research, University of Liverpool, Liverpool, Merseyside, UK.
authors.forename: Alistair C
authors.initials: AC
authors.lastname: Darby
authors.affiliation: Institute of Infection & Global Health, Liverpool Science Park IC2, University of Liverpool, Liverpool, Merseyside, UK.
authors.forename: A Christina
authors.initials: AC
authors.lastname: Gill
authors.affiliation: Institute of Infection & Global Health, Liverpool Science Park IC2, University of Liverpool, Liverpool, Merseyside, UK.
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Armstrong
authors.affiliation: Institute of Infection & Global Health, Liverpool Science Park IC2, University of Liverpool, Liverpool, Merseyside, UK.
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Hartley
authors.affiliation: Institute of Infection & Global Health, Liverpool Science Park IC2, University of Liverpool, Liverpool, Merseyside, UK.
authors.forename: Dong
authors.initials: D
authors.lastname: Xia
authors.affiliation: Institute of Infection & Global Health, Liverpool Science Park IC2, University of Liverpool, Liverpool, Merseyside, UK.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Wastling
authors.affiliation: Institute of Infection & Global Health, Liverpool Science Park IC2, University of Liverpool, Liverpool, Merseyside, UK.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Makepeace
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000251:Adenosine Triphosphatases / Q000235:genetics; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001181:Arthropods / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics; D002460:Cell Line; D004318:Doxycycline / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D026901:Membrane Transport Proteins / Q000235:genetics; D040901:Proteomics; D012329:RNA, Bacterial / Q000235:genetics; D022661:RNA, Untranslated; D013312:Stress, Physiological / Q000235:genetics*; D020577:Wolbachia / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism
chemical_list: C411065:6S RNA; D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D012329:RNA, Bacterial; D022661:RNA, Untranslated; D000251:Adenosine Triphosphatases; C120060:phosphate import ATP-binding protein, Bacteria; D004318:Doxycycline