Project description:We discovered that mice with hematopoietic-specific deletion of Lsd1 lacked Gr-1+ Mac1+ neutrophilic granulocytes whereas the numbers of Gr-1dim Mac1+ granulocytic progenitor cells was increased. To determine the genes altered by Lsd1-loss, Gr-1dim Mac1+ granulocytic progenitor cells from Lsd1fl/fl and Lsd1fl/fl Mx1Cre mice were FACS-purified to be analyzed by gene expression profiling.
Project description:We discovered that mice with hematopoietic-specific deletion of Lsd1 lacked Gr-1+ Mac1+ neutrophilic granulocytes whereas the numbers of Gr-1dim Mac1+ granulocytic progenitor cells was increased. To determine the genes altered by Lsd1-loss, Gr-1dim Mac1+ granulocytic progenitor cells from Lsd1fl/fl and Lsd1fl/fl Mx1Cre mice were FACS-purified to be analyzed by gene expression profiling. Primary Gr-1dim Mac1+ granulocytic progenitor cells were isolated from the bone marrow of Lsd1fl/fl and Lsd1fl/fl Mx1Cre animals by FACS-sorting, one week after the final p(I:C) dose. Total RNA from three biological replicates per genotype was extracted and used to hybridize to Affymetrix expression arrays using the Mouse Genome 430 2.0 array platform.
Project description:Here we describe that lysine-specific demethylase 1 (Lsd1/KDM1a), which demethylates histone H3 on LysM-bM-^@M-^I4 or LysM-bM-^@M-^I9 (H3K4/K9), is an indispensible epigenetic governor of hematopoietic differentiation. Integrative genomic analysis in primary hematopoietic cells, combining global occupancy of Lsd1, genome-wide analysis of its histone substrates H3K4 mono- and di-methylation and gene expression profiling, reveals that Lsd1 represses hematopoietic stem and progenitor cell (HSPC) gene expression programs during hematopoietic differentiation. We found that Lsd1 function was not restricted to transcription start sites, but is also critical at enhancers. Loss of Lsd1 at these sites was associated with increased H3K4me1 and H3K4me2 methylation levels on HSPC genes and their derepression. Failure to fully silence HSPC genes compromised differentiation of hematopoietic stem cells and mature blood cell lineages. Our data indicate that Lsd1-mediated concurrent repression of enhancer and promoter activity of stem and progenitor cell genes is a pivotal epigenetic mechanism required for proper hematopoietic maturation. To identify direct target genes of Lsd1 in myeloid cells we mapped global occupancy of Lsd1 in 32D granuolocytic progenitor cells and compared H3K4me1/me2/me3 and H3K27ac histone modifications in Lsd1fl/fl (wild type) vs. Lsd1fl/f Mx1Cre (knockout) Gr1dim Mac1 granuolocytic progenitor cells.
Project description:We discovered that mice that lack Lsd1 in hematopoietic cells were exhibited increased frequencies of CD150+ CD48- lin- c-Kit+ Sca-1+ LT-HSCs, but completely lacked the lin- c-Kit+ Sca-1- myeloid progenitor compartment. To determine the genes altered by Lsd1-loss, CD150+ CD48- lin- c-Kit+ Sca-1+ LT-HSCs from Lsd1fl/fl and Lsd1fl/fl Mx1Cre mice were FACS-purified to be analyzed by gene expression profiling.
Project description:Cellular binary fate decisions require the progeny to silence genes associated with the alternative fate. The major subsets of alpha:beta T cells have been extensively studied as a model system for fate decisions. While the transcription factor RUNX3 is required for the initiation of Cd4 silencing in CD8 T cell progenitors, it is not required to maintain the silencing of Cd4 and other helper T lineage genes. The other runt domain containing protein, RUNX1, silences Cd4 in an earlier T cell progenitor, but this silencing is reversed whereas the gene silencing after RUNX3 expression is not reverse. Therefore, we hypothesized that RUNX3 and not RUNX1 recruits other factors that maintains the silencing of helper T lineage genes in CD8 T cells. To this end, we performed a proteomics screen of RUNX1 and RUNX3 to determine candidate silencing factors.
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:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.