PMC:509305 / 9445-18236 JSON TXT

Annnotations TAB JSON ListView MergeView

craft-ca-core-dev

craft-sa-dev

2_test

{"project":"2_test","denotations":[{"id":"15314659-423976-84764697","span":{"begin":5264,"end":5268},"obj":"423976"},{"id":"15314659-7389204-84764698","span":{"begin":5283,"end":5287},"obj":"7389204"},{"id":"15314659-8662234-84764699","span":{"begin":5621,"end":5625},"obj":"8662234"},{"id":"15314659-8013918-84764700","span":{"begin":7392,"end":7396},"obj":"8013918"},{"id":"T88647","span":{"begin":5264,"end":5268},"obj":"423976"},{"id":"T91165","span":{"begin":5283,"end":5287},"obj":"7389204"},{"id":"T82964","span":{"begin":5621,"end":5625},"obj":"8662234"},{"id":"T36122","span":{"begin":7392,"end":7396},"obj":"8013918"}],"text":"Mapping of Loci Predisposing to Lupus in the Hybrid Strain (129 × C57BL/6)\nMice were genotyped with 143 microsatellite markers distributed throughout the autosomes such that 98% of the genes were within 20 cM of an informative marker. A summary of the genome-wide linkage analysis for each of the disease traits measured is shown in Table 3. The areas of linkage were defined according to the parental origin, 129 or C57BL/6. Only linkages identified in both experimental groups are reported in Table 3, with the exception of the Chromosome 1 distal segment, where the linkage analysis could not be applied to the (129 × C57BL/6)F2.Apcs −/− mice as this region was of fixed 129 origin. Chromosomes where linkages were present only in one of the two cohorts are shown in Figures 1–3.\nFigure 1 Linkage of Chromosome 2 with ANA and Anti-Chromatin Abs in (129 × C57BL/6)F2.Apcs−/− Mice\nThese associations were not detected in (129 × C57BL/6)F2 animals. Centimorgan positions were deduced by interval mapping, anchoring marker locations to data from http://www.informatics.jax.org. Dotted lines and the dashed line indicate the threshold over which linkages were considered suggestive or significant, respectively, as defined in Materials and Methods.\nFigure 3 Linkage of Chromosome 4 with Anti-dsDNA Abs\nThe estimated peak in (129 × C57BL/6)F2 mice was at position 51.3 cM, whilst in the (129 × C57BL/6)F2.Apcs−/−animals it was was at position 71 cM, indicating that most likely these were two independent loci. Centimorgan positions were deduced by interval mapping, anchoring marker locations to data from http://www.informatics.jax.org. Dotted lines the indicate threshold over which linkage was considered suggestive, as defined in Materials and Methods.\nTable 3 Summary of Genome-Wide Linkage Analysis in Apcs −/− and Wild-Type (129 × C57BL/6)F2 Female Mice\na Suggestive linkage\nb Significant linkage\nc Highly significant linkage as defined in the material and method section\nChr, Chromosome; Est. Peak, Estimated Peak; LOD, logarithm of odds; N/A, not applicable\nChromosomes where linkages were not present in both experimental groups are not illustrated. See Materials and Methods for details. The oligonucleotide sequences and approximate positions of the microsatellite markers used were taken from the Mouse Genome Database, Mouse Genome Informatics, Jackson Laboratory, Bar Harbor, Maine, United States (http://www.informatics.jax.org) The quantitative trait linkage (QTL) analysis identified several intervals on Chromosome 1 with linkage to disease serological markers, and these regions were all derived from the 129 mouse strain (see Table 3; Figures 4 and 5). Interestingly, whilst ANA and anti-chromatin Ab levels showed suggestive or significant linkages only to the telomeric region of Chromosome 1, with an estimated peak occurring at a position approximately 90 cM near the Apcs gene, anti-dsDNA or anti-ssDNA Ab production was also linked to other segments on Chromosome 1, indicating a more complex genetic contribution from the 129 mouse strain.\nFigure 4 Interval Mapping Scans Showing QTL on Chromosome 1 with Anti-dsDNA and Anti-ssDNA Abs\nCentimorgan positions were deduced by interval mapping, anchoring marker locations to data from http://www.informatics.jax.org. Dotted lines indicate the threshold over which linkage was considered suggestive, dashed lines indicate the threshold over which linkage was considered significant, and dotted/dashed lines indicate highly significant linkage, as defined in Materials and Methods. See Table 3 for additional details.\nFigure 5 Interval Mapping Scans Showing QTL on Chromosome 1 with ANA and Anti-Chromatin Abs\nCentimorgan positions were deduced by interval mapping, anchoring marker locations to data from http://www.informatics.jax.org. Dotted lines indicate the threshold over which linkage was considered suggestive, and dashed lines indicate the threshold over which linkage was considered significant, as defined in Materials and Methods. See Table 3 for additional details. Guided by these observations, we investigated whether the increased levels of ANA and anti-chromatin Ab observed in the Apcs −/− mice were caused by a gene(s) within the fixed 129 region surrounding the mutated Apcs gene, rather than caused by the mutated Apcs gene itself. We compared the levels of these auto-Abs between all (129 × C57BL/6)F2.Apcs −/− mice and a group of 33 wild-type mice that were selected for being homozygous 129 in the region of Chromosome 1 between microsatellites D1Mit105 and D1Mit 223 (80–106 cM) (Figure 6A–6D). In contrast to the results reported in Table 1, this comparison showed no significant differences between the two experimental groups. This result demonstrates that, most likely, the 129-derived region and not the lack of Apcs was mediating the production of ANA and anti-chromatin Ab. Consistent with this explanation, we found that the 129 mice have significantly higher levels of Apcs in circulation compared with the C57BL/6 mice (median, 83 mg/l; range, 25–208; n = 16 versus median, 5 mg/l; range, 4–9; n = 10, respectively; p \u003c 0.0001). The C57BL/6 strain has previously been reported to be one of the murine strains defined as low Apcs producers (Pepys et al. 1979; Baltz et al. 1980). In addition, sequence analysis of the entire Apcs coding region in both strains failed to identify any coding sequence polymorphisms in the Apcs gene (data not shown), indicating that a structural variant of the protein is unlikely to be the explanation for our findings. This is consistent with a previous report by Drake et al. (1996) that showed no Apcs coding sequence differences amongst several autoimmune and nonautoimmune murine strains.\nFigure 6 Auto-Ab Profiles\n(A) ANA titres in the (129 × C57BL/6)F2.Apcs −/− mice and (129 × C57BL/6)F2 at 1 y of age. A small circle represents one mouse; a large circle, a variable number of animals, as indicated in parentheses. Serum samples were titrated to endpoint.\n(B) ANA titres in the (129 × C57BL/6)F2.Apcs −/− mice and a selected number of wild-type (129 × C57BL/6)F2 animals carrying the Chromosome 1 region between D1Mit105 and D1Mit223 (80–106 cM) of 129 origin. The symbols are as in (A).\n(C and D) Anti-chromatin Ab levels expressed in AEUs related to a standard positive sample, which was assigned a value of 100 AEU. The comparison is between the same groups of mice as in (A) and (B), respectively. The symbols are as in (A). In addition to the 129-derived segments, in both cohorts the C57BL/6 strain contributed to the autoimmune traits with one major susceptibility locus on Chromosome 3. A genomic region between D3Mit40 and D3Mit13, with an estimated peak at position approximately 51 cM, showed a significant linkage to ANA production and weaker linkages to anti-ssDNA and anti-chromatin production (see Table 3; Figure 7). The high frequency of autoimmune phenotype in the (129 × C57BL/6) hybrid genetic background and its absence in either of the inbred parental strains imply that there are essential interactions between 129- and C57BL/6-derived alleles for the expression of autoimmunity. We investigated further the effects of genes from the C57BL/6 background by repeating the linkage analysis in (129 × C57BL/6)F2 mice, whilst controlling for the very strong 129 effect on distal Chromosome 1, as previously described (Zeng 1994). The results of this analysis showed that the statistical support for the linkage of the C57BL/6 locus on Chromosome 3 for ANA increased from logarithm of odds (LOD) 5.4 to LOD 6.4.\nFigure 7 Interval Mapping Scans Showing QTL on Chromosome 3 with ANA, Anti-Chromatin, and Anti-ssDNA Abs\nSee Table 3 for additional details. Centimorgan positions were deduced by interval mapping, anchoring marker locations to data from http://www.informatics.jax.org. Dotted lines indicate the threshold over which linkage was considered suggestive, the dashed line indicate the threshold over which linkage was considered significant, and dotted/dashed lines indicate highly significant linkage, as defined in Materials and Methods. In contrast to these strong associations with disease serological markers, the QTL analysis identified only two potential linkages to glomerulonephritis: one in the wild-type mice on Chromosome 7 across a 10 cM region between D7Mit246 (15 cM) and D7Mit145 (26.5 cM) of 129 origin (LOD 2.86, p = 0.0013), and one on Chromosome 17 between D17Mit100 (11.7 cM) and D17Mit216 (29.4 cM) from the C57BL/6 strain (LOD 1.3, p = 0.049 and LOD 1.67, p = 0.021 in the wild-type and Apcs −/− mice, respectively). Histological evidence of glomerulonephritis was only found in approximately 20% of the mice in each cohort, which reduces the power of the QTL analysis for this disease trait."}

craft-ca-core-ex-dev

PMC:509305 / 9445-18236 JSONTXT

Annnotations TAB JSON ListView MergeView

craft-ca-core-dev

craft-sa-dev

2_test

craft-ca-core-ex-dev

PMC:509305 / 9445-18236 JSON TXT