Send to

Choose Destination
Infect Immun. 2009 Jan;77(1):232-44. doi: 10.1128/IAI.00978-08. Epub 2008 Oct 27.

Genome-wide screen in Francisella novicida for genes required for pulmonary and systemic infection in mice.

Author information

Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.


Francisella tularensis is a gram-negative, highly infectious, aerosolizable facultative intracellular pathogen that causes the potentially life-threatening disease tularemia. To date there is no approved vaccine available, and little is known about the molecular mechanisms important for infection, survival, and dissemination at different times of infection. We report the first whole-genome screen using an inhalation mouse model to monitor infection in the lung and dissemination to the liver and spleen. We queried a comprehensive library of 2,998 sequence-defined transposon insertion mutants in Francisella novicida strain U112 using a microarray-based negative-selection screen. We were able to track the behavior of 1,029 annotated genes, equivalent to a detection rate of 75% and corresponding to approximately 57% of the entire F. novicida genome. As expected, most transposon mutants retained the ability to colonize, but 125 candidate virulence genes (12%) could not be detected in at least one of the three organs. They fell into a variety of functional categories, with one-third having no annotated function and a statistically significant enrichment of genes involved in transcription. Based on the observation that behavior during complex pool infections correlated with the degree of attenuation during single-strain infection we identified nine genes expected to strongly contribute to infection. These included two genes, those for ATP synthase C (FTN_1645) and thioredoxin (FTN_1415), that when mutated allowed increased host survival and conferred protection in vaccination experiments.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center