Project description:Neural precursor cells from the ganglionic eminence at E14.5 were isolated and cultured as neurospheres. E2F3 and E2F4 genomic binding sites are mapped by ChIP-on-Chip on wild type or mutant cells.
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:To characterize the genetic basis of hybrid male sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven ‘hotspots,’ seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL - but not cis eQTL - were substantially lower when mapping was restricted to a ‘fertile’ subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility.
Project description:ZBTB38 is a transcription factor with affinity for methylated sequences in vitro. Here, we address ZBTB38 binding selectivity in vivo by mapping 3232 ZBTB38 binding sites throughout the human genome. These target sites are over-represented in Alu-repeats, and in the CpG island shores of highly expressed genes, hundreds of base pairs upstream of the transcription start site. In addition, the ZBTB38 target sites are highly similar to E2F4-binding motifs, but they are methylated, not bound by E2F4, and the corresponding genes are not cell-cycle regulated.
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 use ChIP-seq to discover the genome-wide sites of acetylation of lysine 56 of the histone H3 (H3K56), which is a target of three histone modifying enzymes with known roles in diabetes and insulin resistance, in human adipocytes derived from mesenchymal stem cells. Surprisingly, we find that a very large fraction of genes show some level of acetylation on H3K56, but the highest levels of acetylation are associated with genes previously reported to be involved in type 2 diabetes. Using computational methods, we propose that the transcription factor E2F4 may be involved in recruiting histone modifying enzymes to these sites. We confirm this prediction by measuring the binding of E2F4 using ChIP-seq. We also examine the binding of two other proteins using ChIP-Seq: HSF-1 and C/EBPM-NM-1M-BM- . HSF-1 is a master regulator of stress responses, and is a target of the same histone modifiers as H3K56. We find a high degree of overlap between HSF-1 binding and H3K56 acetylation even in cells that are not stressed. By contrast, C/EBPM-NM-1M-BM- , which is not known to be modified by these enzymes, shows much less overlap with the sites of H3K56 acetylation. Our results represent the first mapping of the regulatory code of human adipocytes. Examination of H3K56 acetylation sites and E2F4,C/EBPM-NM-1 and HSF-1 binding sites in human adipocytes.
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.