Ftir1^C57BL/6J
QTL Variant Detail

Summary

• QTL variant: Ftir1^C57BL/6J
• Name: Francisella tularensis infection repsonse 1; C57BL/6J
• MGI ID: MGI:5909260
• QTL: Ftir1 Location: unknown Genetic Position: Chr19, Syntenic

Variant origin

• Strain of Specimen: C57BL/6J

Variant description

• Allele Type: QTL

Notes

Mapping and Phenotype information for this QTL, its variants and associated markers

J:240144

Differences among individuals in susceptibility to infectious diseases can be modulated by host genetics. In mice, A/J (AJ) and C57BL/6J (B6) mice show differential susceptibilities to various pathogens, including the intracellular pathogen Francisella tularensis.

Since macrophages are considered the primary target site for Francisella infection and replication, the current study used AXB/BXA recombinant inbred (RI) mice and their progenitors (AJ and B6 mice) to investigate the relationship between macrophage genotype and response to F. tularensis.

Mice were infected intranasally with 250 CFU of F. tularensis LVS in sterile phosphate-buffered saline (PBS) (50l) and followed for survival or bacterial burden. To determine bacterial burden, mice were euthanized and specific tissues (lung, spleen, and liver) were collected 6 days after infection.

The differences in bacterial counts were evident at the initial stage of infection (2 h after infection) (Fig. 2B), whereas at the later time point (24 h) there was no significant difference between bacterial counts in bone marrow derived macrophages (BMDMs) from the two sources.

To assess the relevance of the results to infection with a fully virulent strain, F. tularensis SchuS4 bacterial proliferation was tested in the BMDMs. Similarly to the LVS, SchuS4 had a higher bacterial growth index in AJ macrophages than in B6 cells, with significantly different bacterial counts at 2 h but not at 24 h after infection.

934 AXB/BXA genetic informative markers obtained from http://www.genenetwork.org to perform a genome-wide scan in R/qtl (NCBI Build 37). The significance of QTL LOD scores was assessed with 1,000 permutations of the phenotype data,and the correspondingP values were reported. QTL significance was reported at a genome-wide threshold corresponding to P values of <0.05.

QTL analysis revealed QTL Ftir1, Francisella tularensis infection repsonse 1, mapping to Chromosome 19, peaking at 22.410 Mb with a LOD score of 3.0 that was associated with bacterial counts 2 hours after infection.

References

• Original: J:240144 Fink A, et al., Early Interactions of Murine Macrophages with Francisella tularensis Map to Mouse Chromosome 19. mBio. 2016 Mar 15;7(2):e02243
• All: 1 reference(s)