Streamlined copper defenses make Bordetella pertussis reliant on custom-made operon

Copper is both essential and toxic to living beings, which tightly controls its intracellular concentration. At the host–pathogen interface, copper is used by phagocytic cells to kill invading microorganisms. We investigated copper homeostasis in Bordetella pertussis, which lives in the human respiratory mucosa and has no environmental reservoir. B. pertussis has considerably streamlined copper homeostasis mechanisms relative to other Gram-negative bacteria. Its single remaining defense line consists of a metallochaperone diverted for copper passivation, CopZ, and two peroxide detoxification enzymes, PrxGrx and GorB, which together fight stresses encountered in phagocytic cells. Those proteins are encoded by an original, composite operon assembled in an environmental ancestor, which is under sensitive control by copper. This system appears to contribute to persistent infection in the nasal cavity of B. pertussis-infected mice. Combining responses to co-occurring stresses in a tailored operon reveals a strategy adopted by a host-restricted pathogen to optimize survival at minimal energy expenditure.

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Jacob-Dubuisson Françoise
Oct 27, 2020 To analyse the genetic environment of a gene of interest (prxgrx), the protein nr NCBI sequence database was searched for occurrence of Redoxin and Glutaredoxin domains signatures using hmmsearch from the HMMER package and the Redoxin.hmm and Glutaredoxin.hmm files downloaded from the Pfam database. A custom python script was used to select proteins carrying both domains. The sequence redundancy of the protein set was reduced using the cd-hit program form the CD-HIT Suite. The Pfam domains of the different proteins were defined using the Pfam Domain Search function of the CLC main Workbench software. The Taxonomy of the protein set was defined using the Bio.Entrez module of the BioPython package. The genetic environment of the genes coding for the different proteins was established using an in-house python script that parses the GenBank files of a local prokaryotic database composed of GenBank files from the BCT, ENV and CON divisions as well as RefSeq and WGS data. Data Policy information about availability of data All manuscripts must include a data availability statement. This statement should provide the following information, where applicable: -Accession codes, unique identifiers, or web links for publicly available datasets -A list of figures that have associated raw data -A description of any restrictions on data availability Field-specific reporting Please select the one below that is the best fit for your research. If you are not sure, read the appropriate sections before making your selection.

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All studies must disclose on these points even when the disclosure is negative. To access proteomic data : -Project Name: Streamlining of defenses against copper makes host-restricted pathogen reliant on custom-made operon -Project accession: PXD020900 -Project DOI: 10.6019/PXD020900 All in vitro experiments and their statistical analyses were performed using at least 3 biological replicates. For the animal colonization experiment there were 4 mice per time point for wild type bacteria (as the colonisation kinetics of this strain is well known) and 5 mice per time point for the mutant strain. The first time point was performed with only 3 mice per group to check for similar bacterial loads in mice at the beginning of the experiment.
Two mice were excluded from the experiments: one died upon anesthesis, and the other was sacrificed because of another infection. The values obtained with the latter mouse were discarded.
In addition to biological and technical replicates, all experiments (except animal colonization) were repeated at least 2 times independently.
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