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:We used microarrays to analyze gene expression changes in the Ikaros null ILC87 T cell tumor line after re-expression of Ikaros. ILC87 cells were transduced to stably express the 4-hydroxytamoxifen-inducible (4OHT) Ikaros1-ER fusion protein. ILC87-Ik1-ER cells were treated with mock (EtOH) or 4OHT for 1 day and the global gene expression changes were assessed by microarray analysis.
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:Ikaros encodes a transcription factor that functions as a tumor suppressor in T-ALL. The mechanisms through which Ikaros regulates gene expression and cellular proliferation in T-ALL are unknown. Re-introduction of Ikaros into Ikaros-null T-ALL cells results in cessation of cellular proliferation and induction of T-cell differentiation. We performed dynamic global epigenomic and gene expression analyses to determine the role of Ikaros in tumor suppression during this process. Our results identified novel Ikaros functions in the epigenetic regulation of gene expression: Ikaros directly regulates de novo formation and depletion of enhancers, as well as de novo formation of active enhancers and activation of poised enhancers; Ikaros directly induces the formation of super-enhancers; and Ikaros demonstrates pioneering activity by directly regulating chromatin accessibility. Dynamic analyses demonstrate the long-lasting effect of Ikaros DNA binding on enhancer activation, de novo formation of enhancers and super-enhancers, and chromatin accessibility. Ikaros induces profound, global re-distribution of HDAC1 via recruitment of HDAC1 to promoter and enhancer regions of different target genes. Expression analysis identified a large number of novel signaling pathways that are directly regulated by Ikaros and Ikaros-induced enhancers, and that are responsible for the cessation of proliferation and induction of T-cell differentiation in T-ALL cells.
Project description:Ikaros encodes a transcription factor that functions as a tumor suppressor in T-ALL. The mechanisms through which Ikaros regulates gene expression and cellular proliferation in T-ALL are unknown. Re-introduction of Ikaros into Ikaros-null T-ALL cells results in cessation of cellular proliferation and induction of T-cell differentiation. We performed dynamic global epigenomic and gene expression analyses to determine the role of Ikaros in tumor suppression during this process. Our results identified novel Ikaros functions in the epigenetic regulation of gene expression: Ikaros directly regulates de novo formation and depletion of enhancers, as well as de novo formation of active enhancers and activation of poised enhancers; Ikaros directly induces the formation of super-enhancers; and Ikaros demonstrates pioneering activity by directly regulating chromatin accessibility. Dynamic analyses demonstrate the long-lasting effect of Ikaros DNA binding on enhancer activation, de novo formation of enhancers and super-enhancers, and chromatin accessibility. Ikaros induces profound, global re-distribution of HDAC1 via recruitment of HDAC1 to promoter and enhancer regions of different target genes. Expression analysis identified a large number of novel signaling pathways that are directly regulated by Ikaros and Ikaros-induced enhancers, and that are responsible for the cessation of proliferation and induction of T-cell differentiation in T-ALL cells.
Project description:Ikaros encodes a transcription factor that functions as a tumor suppressor in T-ALL. The mechanisms through which Ikaros regulates gene expression and cellular proliferation in T-ALL are unknown. Re-introduction of Ikaros into Ikaros-null T-ALL cells results in cessation of cellular proliferation and induction of T-cell differentiation. We performed dynamic global epigenomic and gene expression analyses to determine the role of Ikaros in tumor suppression during this process. Our results identified novel Ikaros functions in the epigenetic regulation of gene expression: Ikaros directly regulates de novo formation and depletion of enhancers, as well as de novo formation of active enhancers and activation of poised enhancers; Ikaros directly induces the formation of super-enhancers; and Ikaros demonstrates pioneering activity by directly regulating chromatin accessibility. Dynamic analyses demonstrate the long-lasting effect of Ikaros DNA binding on enhancer activation, de novo formation of enhancers and super-enhancers, and chromatin accessibility. Ikaros induces profound, global re-distribution of HDAC1 via recruitment of HDAC1 to promoter and enhancer regions of different target genes. Expression analysis identified a large number of novel signaling pathways that are directly regulated by Ikaros and Ikaros-induced enhancers, and that are responsible for the cessation of proliferation and induction of T-cell differentiation in T-ALL cells.