Project description:We used microarrays to perform a global gene expression analysis in Tcf1-expressing Thy1+CD25+ T lineage cells that develop on OP9 stroma in the absence of Notch1 signals. We compare this to the starting population, LMPP progenitors, and to control expressing T lineage cells that developed on OP9 stroma expressing Notch ligand DL4. The overall goal of this study was to determine if Tcf1 initiates T lineage specification in lymphoid progenitors. We found that Tcf1 was sufficient to upregulate many T lineage genes as compared to control expressing progenitors on OP9-DL4. Abstract of manuscript: The thymus imposes the T cell fate on incoming multipotent progenitors, but the molecular mechanisms are poorly understood. We show that transcription factor Tcf1 initiates T-lineage-specific gene expression. Tcf1 is downstream of Notch1 signaling and expressed in early T-cell progenitors. Progenitors deficient for Tcf1 are unable to initiate normal T-lineage specification. Conversely, ectopic expression of Tcf1 in hematopoietic progenitors is sufficient to induce expression of T-lineage specific genes in vitro. Thus, our study identifies Tcf1 as critically involved in the establishment T cell identity. Wiltype LMPPs were isolated by a FACSAria cell sorter and retrovirally transduced with a Tcf1-containing (Tcf1-VEX) or control vector (VEX) retrovirus. Tcf1-expressing cells and control-vector expressing cells were then seeded on OP9 stroma or OP9 stroma expressing Notch ligand DL4, respectively. On day 10, Thy1+CD25+ T lineage cells were sorted from Tcf1-expressing cells on OP9 stroma and compared to sorted LMPPs and Thy1+CD25+ T lineage cells that developed from control-vector expressing cells on OP9-DL4.
Project description:Tcf1 is necessary for optimal T lineage development. Tcf1 deficient progenitors fail to initiate the T lineage program in vitro and development is severely defective in vivo. We used microarrays to assess the overal global gene expression differences from Tcf1 wildtype and deficient lymphoid biased progenitors cultures on Notch-ligand expressing stroma to determine if Tcf1 deficient progenitors are able to intiate the T lineage specification program. Abstract of manuscript: The thymus imposes the T cell fate on incoming multipotent progenitors, but the molecular mechanisms are poorly understood. We show that transcription factor Tcf1 initiates T-lineage-specific gene expression. Tcf1 is downstream of Notch1 signaling and expressed in early T-cell progenitors. Progenitors deficient for Tcf1 are unable to initiate normal T-lineage specification. Conversely, ectopic expression of Tcf1 in hematopoietic progenitors is sufficient to induce expression of T-lineage specific genes in vitro. Thus, our study identifies Tcf1 as critically involved in the establishment T cell identity. Tcf1 wildtype and deficient bone marrow lymphoid primed progenitors (LMPPs, Lineage marker- Sca+kit+Flt3high) were harvested in triplicate and seeded onto OP9-DL4 expressing stroma for 4 days upon which highly pure lineage negative and Thy1+CD25+ T cells were cell sorted for expression analysis. The lineage negative populations represent three seperate mice from each genotype and the Thy1+CD25+T lineage population represents two replicates from the Tcf1 wildtype group. No Thy1+CD25+ T lineage cells develop from Tcf1 deficient progentiors.
Project description:We used microarrays to perform a global gene expression analysis in Tcf1-expressing Thy1+CD25+ T lineage cells that develop on OP9 stroma in the absence of Notch1 signals. We compare this to the starting population, LMPP progenitors, and to control expressing T lineage cells that developed on OP9 stroma expressing Notch ligand DL4. The overall goal of this study was to determine if Tcf1 initiates T lineage specification in lymphoid progenitors. We found that Tcf1 was sufficient to upregulate many T lineage genes as compared to control expressing progenitors on OP9-DL4. Abstract of manuscript: The thymus imposes the T cell fate on incoming multipotent progenitors, but the molecular mechanisms are poorly understood. We show that transcription factor Tcf1 initiates T-lineage-specific gene expression. Tcf1 is downstream of Notch1 signaling and expressed in early T-cell progenitors. Progenitors deficient for Tcf1 are unable to initiate normal T-lineage specification. Conversely, ectopic expression of Tcf1 in hematopoietic progenitors is sufficient to induce expression of T-lineage specific genes in vitro. Thus, our study identifies Tcf1 as critically involved in the establishment T cell identity.
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: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:HIV cure efforts are increasingly focused on harnessing CD8 T cell functions; however, a deeper understanding of CD8 T cells promoting HIV control is necessary to properly inform therapeutic approaches. Here, we identified a novel TOX-expressing CD8 T cell population associated with control of SIV infection in lymphoid tissue of rhesus macaques defined as an antigen-responsive TCF1+ CD39+ subset expressing high levels of TOX and inhibitory receptors but lower levels of canonical cytolytic molecules such as granzyme B, granzyme A, and perforin. Transcriptional analysis of SIV-specific CD8 T cells, as well as proteomic analysis of purified CD8 T cell subsets, revealed these TCF1+ CD39+ cells as an intermediate effector population retaining stem-like features while maintaining a lineage relationship with terminal effector cells. TCF1+ CD39+ CD8 T cells expressed higher levels of CXCR5 than terminally differentiated cells, were found at higher frequency in follicular micro-environments, and were preferentially located in the proximity of SIV-RNA+ cells both in lymph node T cell zone and B cell follicles. Importantly, their frequency was strongly associated with reduced plasma viremia and lower reservoir size. Finally, we confirmed the presence of a highly similar TOX-enriched TCF1+ CD39+ cell population in lymph node biopsies from ART-naïve and ART-treated people living with HIV. Collectively, these data identify a unique population of lymphoid CD8 T cells possessing both stem-like and effector properties that contribute to limiting HIV/SIV persistence.
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.
Project description:Expression data from Tcf1 deficient and Tcf1 wildtype cultured bone marrow lymphoid primed progenitors after four days on Notch ligand expressing stroma (OP9-DL4).