title: Long-term survival of Borrelia burgdorferi lacking the hibernation promotion factor homolog in the unfed tick vector.
abstract: Borrelia burgdorferi, a causative agent of Lyme borreliosis, is a zoonotic pathogen that survives in nutrient-limited environments within a tick, prior to transmission to its mammalian host. Survival under these prolonged nutrient-limited conditions is thought to be similar to survival during stationary phase, which is characterized by growth cessation and decreased protein production. Multiple ribosome-associated proteins are implicated in stationary-phase survival of Escherichia coli. These proteins include hibernation-promoting factor (HPF), which dimerizes ribosomes and prevents translation of mRNA. Bioinformatic analyses indicate that B. burgdorferi harbors an hpf homolog, the bb0449 gene. BB0449 protein secondary structure modeling also predicted HPF-like structure and function. However, BB0449 protein was not localized in the ribosome-associated protein fraction of in vitro-grown B. burgdorferi. In wild-type B. burgdorferi, bb0449 transcript and BB0449 protein levels are low during various growth phases. These results are inconsistent with patterns of synthesis of HPF-like proteins in other bacterial species. In addition, two independently derived bb0449 mutants successfully completed the mouse-tick infectious cycle, indicating that bb0449 is not required for prolonged survival in the nutrient-limited environment in the unfed tick or any other stage of infection by B. burgdorferi. We suggest either that BB0449 is associated with ribosomes under specific conditions not yet identified or that BB0449 of B. burgdorferi has a function other than ribosome conformation modulation.
authors.affiliation: Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Fazzino
authors.affiliation: Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA ktilly@niaid.nih.gov prosa@niaid.nih.gov.
authors.forename: Kit
authors.initials: K
authors.lastname: Tilly
authors.affiliation: Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Dulebohn
authors.affiliation: Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA ktilly@niaid.nih.gov prosa@niaid.nih.gov.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Rosa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D025065:Borrelia burgdorferi / Q000235:genetics* / Q000472:pathogenicity; D017124:Conserved Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006605:Hibernation / Q000235:genetics; D018884:Ixodes / Q000254:growth & development / Q000382:microbiology*; D007814:Larva / Q000254:growth & development / Q000382:microbiology; D008193:Lyme Disease / Q000276:immunology / Q000382:microbiology / Q000473:pathology / Q000635:transmission; D051379:Mice; D050296:Microbial Viability; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012269:Ribosomal Proteins / Q000235:genetics* / Q000276:immunology; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D012269:Ribosomal Proteins