Experiment
Disease phenotypes associated with Leishmania major infection were mapped in animals from (CcS-16 x BALB/cHeA)F2 and (CcS-20 x BALB/cHeA)F2 intercross populations. CcS-16 and CcS-20 are recombinant congenic (RC) strains derived from STS/A and BALB/cHeA. Animals were infected with Leishmania major after 9 weeks of age and sacrificed 8 weeks post-infection.
F2 hybrids between BALB/c and CcS20/Dem and F2 hybrids between BALB/c and CcS16 were tested from clinical and immunological consequences post infection. They were genotyped with mircosatellite markers covering the STS-derived segments. Linkage analysis of differing pathological and immunological parameters indicated novel loci and novel functions for previously mapped loci.
In the (BALB/c x CcS20)F2 intercross a Chromosome 5 QTL linked to D5Mit55 and D5Mit114 was identified, text refers to this QTL as Lmr3.
03.18.2016 Curator Note: Because Lmr3 was orginally mapped in J:82715 using a (BALB/c x CcS5)F2 mapping population, which differs from the cross used here, we consider the current study a separate mapping experiment and have equated this QTL with Lmr24, originally identified in J:82717 on Chr 5 using (BALB/c x CcS20)F2 mice.
In the present study the following individual QTL mapped within Lmr24:
Lmr24b was linked with splenomegaly at D5Mit55, corrected p=0.0000646, BALB/c alleles were associated with more severe splenomegaly at Lmr24b.
Lmr24c was identified linked with skin lesions at D5Mit55, corrected p=0.00136, BALB/c alleles were associated with larger skin lesions at Lmr24c.
Lmr24d was linked with splenomegaly at D5Mit114, corrected p=0.00407, BALB/c alleles were associated with more severe splenomegaly at Lmr24d.
Lmr24e was linked with IFN gamma serum levels at D5Mit55, p=0.0484, BALB/c alleles at this locus were associated with higher IFN gamma serum levels; and
Lmr24f, mapping to D5Mit175, was identified in interaction with Lmr17 at D9Mit2 influencing IFN gamma, corrected p=0.0046. Homozygote BALB/c alleles at Lmr24f and homozygous STS/A alleles at Lmr17 (D9Mit2) increase IFN gmma levels.
A novel locus, Lmr26, was also identified mapping to Chromosome 5 with marker D5Mit143, corrected p=0.00477. The BALB/c allele at this locus increased the spontaneous proliferation of spleen cells post infection.
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CcS16 -
Linkage to serum IFN-gamma levels mapped to 52.5 cM on mouse Chromosome 2 near D2Mit102,and linkage to spontaneous spleen cell proliferation mapped to 50.3 cM near D2Mit389. This locus is identified as Lmr14 (leishmaniasis resistance 14). STS/A-derived alleles at Lmr14 confer increased serum IFN-gamma and accounts for 5.74% of the variance,while BALB/cHeA-derived alleles confer increased splenocyte proliferation and accounts for 5.11% of the variance. Lmr14 interacts with Lmr5 on chromosome 10 to influence serum IL-12 levels. F2 animals homozygous for STS/A-derived alleles at both Lmr14 and Lmr5 exhibit the highest serum IL-12. This interaction accounts for 8.65% of the variance, and the effect of each individual locus is minimal. Serum TNF-alpha levels are increased in F2 animals homozygous for BALB/cHeA-derived at Lmr14 and Lmr12 on chromosome 16. This interaction accounts for 6.03% of the variance and the effect of each individual locus is minimal. Serum TNF-alpha is lowered by homozygosity for STS/A-derived alleles at Lmr14 and Lmr13 on chromosome 18. This interaction accountsfor 7.24%of the variance, and the effect of each locus individually is minimal. Lmr16 is a novel locus mapping to 99 cM near D2Mit52. Lmr16 does not have an effect by itself but interacts with Lmr18 on chromosome 16 to affect spontaneous splenocyte proliferation. Nfatc2 (95.5 cM) and Cd40 (formerly Tnfrsf5, 97 cM) are potential candidate genes for Lmr18.
Previously identified QTL Lmr11 (leishmaniasis resistance 11) mapped to 44.8 cM on mouse Chromosome 3 near D3Mit49 in linkage with serum IL-6 levels. This locusaccounts for 13.98% of the serum IL-6 variance. STS/A-derived alleles at Lmr11 confer increased serum IL-6 levels.
Previously identified QTL Lmr9 (leishmaniasis resistance 9) mapped to 0 cM on mouse Chromosome 4 near D4Mit149 in linkage with serum IL-6levels.This locus accounts for 14.36% of the serum IL-6 variance. STS/A-derived alleles at Lmr9 confer increased serum IL-6.
Splenomegaly, skin lesion size, and serum IFN-gamma mapped to mouse Chromosome 5 between D5Mit55 (28 cM) and D5Mit114 (44 cM). This locus is the previously identified QTL Lmr3 (leishmaniasis resistance 3). Lmr3 accounts for 5.29% of the splenomegaly variance, 2.7% of the skin lesion size variance, and 5.22% of the serum IFN-gamma variance. BALB/cHeA-derived alleles at Lmr3 conferincreased splenomegaly, skin lesion size, and serum IFN-gamma levels. Lmr3 interacts with Lmr10 on chromosome 8 to influence skin lesion size. F2 animals homozygous for BALB/cHeA-derived alleles at both Lmr3 and Lmr10 exhibit the largest skin lesions. Lmr3 also interacts with Lmr17 on chromosome 9 to influence serum IFN-gamma levels. F2 animals homozygous for BALB/cHeA-derived alleles at Lrm3 and STS/A-derived alleles at Lrm17 exhibit higher serum IFN-gamma concentrations. Lmr3 also shows linkage to spontaneous spleen cell proliferation at D5Mit143 (86 cM), accounting for 0.98% of the variance. BALB/cHeA-derived alleles confer increased spleen cell proliferation.
Linkage to skin lesion size mapped to Lmr4 at 29 cM on mouse Chromosome 6 between D6Mit122and D6Mit10. BALB/cHeA-derived alleles at Lmr4 confer increased skin lesion size. Il12rb2 at 30.1 cM is a potential candidate gene.
Splenomegaly mapped to mouse Chromosome 8 between D8Mit125 (19.5 cM) and D8Mit54 (31 cM). This locus is the previously identified QTL Lmr10 (leishmaniasis 10) and accounts for 5.08% of the variance. BALB/cHeA-derived alleles at Lmr10 confer increased splenomegaly. Lmr10 also shows linkage to skin lesion size and interacts with Lrm3 on chromosome 5. F2 animals homozygous forBALB/cHeA-derived alleles at both Lmr3 and Lmr10 exhibit the largest skin lesions. Lmr10 accounts for 3.89% of the skin lesion variance.
A novel locus named Lmr17 (leishmaniasis resistance 17) mapped to mouse Chromosome 9 at D9Mit2 (17 cM). STS/A-derived alleles at Lmr17 conferincreased serum TNF-alpha levels. This locus accounts for 6.78% of the serum TNF-alpha variance. Lmr7 also interacts with Lmr3 on chromosome 5 to influence serum IFN-gamma levels. F2 animals homozygous for BALB/cHeA-derived alleles at Lrm3 and STS/A-derived alleles at Lrm17 exhibit higher serum IFN-gamma concentrations.
An interaction between novel locus Lmr19 (leishmaniasis resistance 19) on mouse Chromosome 10 near D10Mit67 (49 cM) and Lmr12 on chromosome 16 affects spontaneous spleencellproliferation. F2 animals homozygous for BALB/cHeA-derived alleles at Lmr19 and STS/A-derived alleles at Lmr12 exhibit increased spontaneous spleen cell proliferation. This interaction accounts for 8.53% of the variance and each locus individually has minimal effect.
Serum IFN-gamma levels mapped to 40 cM on mouse Chromosome 11 near D11Mit15. This locus accounts for 10.83% of the variance and is identified as Lmr15 (leishmaniasis resistance 15). STS/A-derived alleles at Lmr15 confer decreased serum IFN-gamma.
Spontaneous spleen cell proliferation mapped to 57.7 cM on mouse Chromosome 16 near D16Mit7. This novel locus is named Lmr18 (leishmaniasis resistance 18). BALB/cHeA-derived alleles at Lmr18 confer decreased spontaneous spleen cell proliferation. Lmr18 interacts with Lmr16 on chromosome 2 to enhance proliferation. F2 animals homozygous for BALB/cHeA-derived alleles at Lmr18 and STS/A-derived alleles at Lmr16 exhibit increased spontaneous spleen cell proliferation. Ifngr2 at 63.3cM is a potential candidate gene for Lmr18. Lmr12 at 32 cM is linked to serum IL-4 levels at D16Mit126. STS/A-derived alleles at Lmr12 confer increased serum IL-4 levels and accounts for 11.1% of the variance. Spontaneous spleen cell proliferation is increased in F2 animals homozygous for STS/A-derived alleles at Lmr12 and BALB/cHeA-derived alleles at Lmr19. This interaction accounts for 8.53% of the variance and each locus individually has minimal effect.
Lmr7 on mouse Chromosome 17 was detected in linkage to spontaneous spleen cell proliferation. BALB/cHeA-derived alleles at Lmr7 confer decreased proliferation.
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