Project description:The microarray analysis of Francisella tularensis subsp. tularensis strains SCHU P9 (virulent) and SCHU P0/P5 (attenuated) revealed significant differences in gene expression. The results showed that 19 genes were upregulated in the virulent SCHU P9 strain, while two genes, including ftt_0965c, were significantly downregulated
Project description:We used an inhalation mouse model of infection to query a collection of 2149 mutants in a Francisella tularensis subsp. novicida background for genes required for growth, survival and systemic dissemination. A microarray-based genome-wide negative selection screen (Microarray tracking of transposon mutants = MATT) allowed us to monitor the behavior of transposon insertions in 1371 unique genes. Interestingly most of these genes persisted in lung and colonized liver and spleen. We found 44 (35%) genes negatively selected in lung and 81 (65%) genes negatively selected in liver and/or spleen. If negative selection in lung occurred, the attenuated mutants in general persisted at 24h after infection, disseminated to liver and/or spleen and appeared to be lost in lung after 48 to 72h of infection. These genes with a strong phenotype in lung but also potential for dissemination might be attractive vaccine or drug candidates. Keywords: Genome-Wide Negative Selection Screen