Fig 1. Identification of genes required for M. tuberculosis seeding in the lung of mice.

(A) Scheme of the TnSeq strategy used. BALB/c mice were infected intranasally with 10⁶ cfu of our H37Rv-derived transposon library. At 1 day and 8 days post-infection, four mice were sacrificed. Part of the lung and spleen homogenates were plated to evaluate bacterial load. The remaining part of the organ homogenates was used to inoculate a culture used for DNA extraction, transposon-junctions amplification and TnSeq analysis. (B) Bacterial load in the lung of mice after 1 and 8 days. Each dot corresponds to a different mouse and the mean of the four mice is indicated. (C) Genes in which insertion were underrepresented in mice after 1 or 8 days of infection in comparison to the inoculum. The list reports only the gene detected both using the ESSENTIAL and TRANSIT softwares; in red, the genes common to the two time points.