Project description:By investigating the germinal center (GC) formation in STAT6ko/WT bone marrow-mixed chimera we found that GC formation in type 2 immune responses is dependent on B cell intrinsic expression of IL-4/IL-13-induced genes. We therefore used microarrays to find Stat6 dependent genes that are important for germinal center formation and/or organization after infection with the nematode Nippostrongylus brasiliensis (N. brasiliensis).
Project description:By investigating the germinal center (GC) formation in STAT6ko/WT bone marrow-mixed chimera we found that GC formation in type 2 immune responses is dependent on B cell intrinsic expression of IL-4/IL-13-induced genes. We therefore used microarrays to find Stat6 dependent genes that are important for germinal center formation and/or organization after infection with the nematode Nippostrongylus brasiliensis (N. brasiliensis). Bone marrow of STAT6ko (CD45.2+) and WT (CD45.1+) were mixed and injected in lethaly irradiated WT (CD45.1+) mice. After 8 weeks, 5 Bone marrow-mixed chimera were infected with N. brasiliensis and draining lymph nodes were collected at day 14 after the infection and pooled. RNA was isolated from sort-purified CD45.1+ or CD45.2+ GC B cells (B220+CD38loGL-7hi).
Project description:IL-4/STAT6-regulated transcriptome and proteome were compared in primary B cells isolated from wild-type and STAT6-deficient mice. B cells were purified from the spleen and stimulated in vitro with anti-CD40 and LPS or anti-IgM-F(ab)2 in the presence or absence of IL-4. Transcriptome analysis was performed with oligonucleotide microarrays. Global relative quantification of proteins was achieved by gel-enhanced label-free liquid chromatography/mass spectrometry (LC/MS). Hierarchical clustering and principal component analysis revealed that IL-4-induced changes of the transcriptome were almost completely dependent on STAT6. In contrast, the quantitative proteome analysis revealed that the expression of many IL-4-regulated proteins changes even in the absence of STAT6. The top 75 proteins with changes in abundance levels induced by IL-4 in a STAT6-dependent manner were also found to be regulated at the transcriptional level. Most of these proteins were not previously known to be regulated by STAT6 in B cells. We confirmed the MS-based quantitative proteome data by flow cytometric and Western blot analysis of selected proteins. This study provides a framework for further functional characterization of STAT6-regulated proteins in B cells that might be involved in germinal center formation and class switch recombination.
Project description:The importance of unanchored Ub in innate immunity has been shown only for a limited number of unanchored Ub-interactors. We investigated what additional cellular factors interact with unanchored Ub and whether unanchored Ub plays a broader role in innate immunity. To identify unanchored Ub-interacting factors from murine lungs, we used His-tagged recombinant poly-Ub chains as bait. These chains were mixed with lung tissue lysates and protein complexes were isolated with Ni-NTA beads. Sample elutions were subjected to mass spectrometry (LC-MSMS) analysis.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.