Project description:The aim of the experiment was to visualize genes under the control of Ikaros during early T cell development. We used mice carrying floxed Ikaros alleles that were crossed with the Rosa26-CreERT2 mice, and which were injected with tamoxifen for 4 days. DN4 thymocytes were sorted from 4 mice (5-6 week-old) which are positive or not for the Rosa26-CreERT2 transgene. DN4 cells were sorted from 2 Ikf/f Rosa26-CreERT2+ mice and 2 Ikf/f mice, which were all treated with tamoxifen for 4 days. Loss of Ikaros was confirmed in sorted cells from the Ikf/f Rosa26-CreERT2+ mice by western blot. Gene expression profiles were determined on total RNA from sorted cells with Affymetrix Mouse Gene arrays.
Project description:T cell development is accompanied by epigenetic changes that ensure the silencing of stem cell-related, and the activation of lymphocyte-specific programs. How transcription factors influence these changes remains unclear. We show that the Ikaros transcription factor interacts with the Polycomb Repressive Complex 2 (PRC2) in CD4-CD8- thymocytes, and allows its binding to >200 developmentally-regulated genes, many of which are expressed in hematopoietic stem cells. Loss of Ikaros in CD4-CD8- cells leads to diminished histone H3 Lys27 (H3K27) trimethylation and ectopic expression of these genes. Ikaros binding triggers PRC2 recruitment and H3K27 trimethylation. Furthermore, Ikaros interacts with PRC2 independently of the Nucleosome Remodeling and Deacetylation complex. Our results identify Ikaros as a fundamental regulator of PRC2 function in developing T cells. Genome-wide comparison of different histone modifications, Ikaros, Suz12 and NuRD binding in different stages of T cell development in WT and Ikaros mutant mice. Profiling of H3K27me3 in DN1, DN2, DN3, DN4 and DP thymocytes and hematopoietic stem and progenitor cells (LSK cells) of WT and Ikaros mutant mice. Profiling of H3K4me3 and H3ac in WT and Ikaros mutant DP thymocytes. Global analysis of Ikaros binding in WT DN3, DN4 and DP cells, Suz12 binding in WT and Ikaros mutant DN3 cells, and Mta2 and Mi2beta binding in WT DN3 cells. Genome-wide profiling of Ikaros binding and H3K27me3 upon Ikaros activation in Ikaros-deficient leukemic T cells.
Project description:The aim of the experiment was to visualize genes under the control of Ikaros during early T cell development. We used mice carrying floxed Ikaros alleles that were crossed with the Rosa26-CreERT2 mice, and which were injected with tamoxifen for 4 days. DN4 thymocytes were sorted from 4 mice (5-6 week-old) which are positive or not for the Rosa26-CreERT2 transgene.
Project description:In order to understand the molecular mechanisms of DN thymocyte development, it may be also of use to clarify how these developmental processes are regulated in terms of their entire gene expression, to which cell differentiation is ultimately ascribed. In the current study, we approached this issue by investigating gene expression profiles in discrete subsets of DN thymocytes under development, in which DN2, DN3, and DN4 thymocytes were sorted and subjected to expression profiling analysis with high-density oligonucleotide microarrays. Experiment Overall Design: The DN2, DN3, and DN4 populations were FACS-sorted from DN thymocytes harvested from four C57BL/6 mice and analyzed by Affymetrix® Mouse Genome 430 2.0 Array® for gene expression. Four independent experiments were performed using 16 mice.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
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.
Project description:The regulation of post-transcriptional modifications of pre-mRNA by alternative splicing is important for cellular function, development and immunity The receptor tyrosine phosphatase CD45, which is expressed on all hematopoietic cells, is known for its role in the development and activation of T cells. To investigate the role of hnRNP L further, we have generated conditional hnRNP L knockout mice carrying floxed alleles and the T-cell specific Lck-Cre recombinase transgene. The Lck-Cre transgene is active in DN3, DN4 as well as in DP and SP cells. We found that deletion of hnRNP L results in a decreased thymic cellularity caused by a partial block at the transition stage between DN4 and DP cells. In addition, hnRNP L-/- thymocytes express aberrant levels of the CD45RA splice isoform and show high levels of phosphorylated Lck at the activator tyrosine Y394 but lacking phosphorylation of the inhibitory tyrosine Y505. This is indicative of an increased basal Lck activation and correlated with a higher proliferation rate of DN4 cells in hnRNP L-/- mice. Deletion of hnRNP L also blocked egress of SP cells to peripheral lymphoid organs and the migration of SP thymocytes in response to the chemokines CCL21 and SDF-1a. Since we found that actin polymerization was also compromised in hnRNP L-/- SP cells, we propose that a defect in the signal transduction cascade downstream of the chemokine receptors CCR7 and CXCR4 caused by the absence of hnRNP L is responsible for this phenotype. Our results indicate that hnRNPL regulates pre-T cell development and migration by regulating CD45 pre-mRNA splicing and chemokine receptor signaling. RNA-seq from Thymocytes from WT mice compared to KO (hnRNP L) mice
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility. Gene expression was measured in whole testis from males aged 62-86 days. Samples include 190 first generation lab-bred male offspring of wild-caught mice from the Mus musculus musculus - M. m. domesticus hybrid zone.