Project description:The winged helix protein FOXA2 and the nuclear receptor PPARg are highly conserved, regionally-expressed transcription factors that regulate networks of genes controlling complex metabolic functions. Cistrome analysis for FOXA2 in mouse liver and PPARg in mouse adipocytes has previously produced consensus binding sites that are nearly identical to those used by the factors in human cells. Despite this conservation of the canonical binding motif, we report here that the great majority of specific binding regions for FOXA2 in human liver and for PPARg in human adipocytes are not in the orthologous locations to the mouse genome. Nevertheless, gene-centric analysis reveals strong shared transcription factor occupancy near genes in tissue-specific metabolic pathways that are functionally conserved across species. Genes with only species-specific binding sites fail to show enrichment for these pathways. Thus, the biological functions of transcription factors that control specific metabolic functions are highly shared across species. Two TFs, FOXA2 and PPARg, were studied for genome-wide conservation of binding between mouse and human in specific tissues/cell-types (liver for FOXA2, adipocytes for PPARg). The number of replicates for each TF was chosen to obtain a comparable number of reads between the TFs and species. Human FOXA2 ChIP-seq was performed on two biological replicates of human liver samples, in three technical replicates each. Input DNA was also collected and sequenced from both biological samples. Mouse FOXA2 ChIP-seq was performed on four biological replicates of mouse liver samples. The ChIP and sequencing were repeated on two of these biological replicates to create technical replicates for additional sequence reads. Input DNA was sequenced from three additional mouse livers. Human PPARg ChIP-seq was performed on a human adipocyte cell-line (SGBS) differentiated in two replicate cultures. Input DNA was also collected and sequenced from one culture. Mouse PPARg ChIP-seq was performed on 3T3-L1 cells differentiated into adipocytes in culture in a single replicate, and this sequence data was pooled with existing data previously generated by the same lab, already available in GEO (GSE21314). A standard pool of input DNA sample sequence from multiple mouse tissue was used for analyzing the Mouse PPARg ChIP-seq data.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:Background and Aims: The forkhead box A (FOXA) family of pioneer transcription factors is critical for the development of many endoderm-derived tissues including the lung and the liver. Here we investigate the role of FOXA2 in regulating intestinal epithelial cell function. Methods: ChIP-seq was used to identify FOXA2 binding sites genome-wide. Targets of FOXA2 were validated using ChIP-qPCR and siRNA-mediated depletion of FOXA1/2 followed by RT-qPCR. A luciferase-based assay was used to measure intracellular cAMP after FOXA1/2 modulation.Results: Peaks of FOXA2 occupancy were frequent at loci contributing to gene ontology pathways of regulation of cell migration, cell motion, and plasma membrane function. Depletion of both FOXA1 and FOXA2 led to a significant reduction in the expression of multiple transmembrane proteins including ion transporters. One of the targets was the adenosine A2B receptor, and reduced receptor mRNA levels were associated with a functional decrease in intracellular cAMP. We also observed that 30% of FOXA2 binding sites contained a GATA motif and that FOXA1/A2 depletion reduced GATA-4, but not GATA-6 protein levels. Conclusions: These data show that FOXA2 plays a critical role in regulating intestinal epithelial cell function. FOXA2 depletion affects the expression of ion transporters and other transmembrane proteins, which form a network essential for maintaining normal ion and solute transport. Moreover, we show that the FOXA and GATA families of transcription factors may work cooperatively to regulate gene expression genome-wide. To determine the role of FOXA2 in regulating gene expression in intestinal epithelial cells, ChIP-seq was performed for FOXA2 in Caco2 (colorectal adenocarcinoma) cells.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
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:Sex differences in liver gene expression are dictated by sex-differences in circulating growth hormone (GH) profiles. Presently, the pituitary hormone dependence of mouse liver gene expression was investigated on a global scale to discover sex-specific early GH response genes that might contribute to sex-specific regulation of downstream GH targets and to ascertain whether intrinsic sex-differences characterize hepatic responses to plasma GH stimulation. RNA expression analysis using 41,000-feature microarrays revealed two distinct classes of sex-specific mouse liver genes: genes subject to positive regulation (class-I) and genes subject to negative regulation by pituitary hormones (class-II). Genes activated or repressed in hypophysectomized (Hypox) mouse liver within 30-90min of GH pulse treatment at a physiological dose were identified as direct targets of GH action (early response genes). Intrinsic sex-differences in the GH responsiveness of a subset of these early response genes were observed. Notably, 45 male-specific genes, including five encoding transcriptional regulators that may mediate downstream sex-specific transcriptional responses, were rapidly induced by GH (within 30min) in Hypox male but not Hypox female mouse liver. The early GH response genes were enriched in 29 male-specific targets of the transcription factor Mef2, whose activation in hepatic stellate cells is associated with liver fibrosis leading to hepatocellular carcinoma, a male-predominant disease. Thus, the rapid activation by GH pulses of certain sex-specific genes is modulated by intrinsic sex-specific factors, which may be associated with prior hormone exposure (epigenetic mechanisms) or genetic factors that are pituitary-independent, and could contribute to sex-differences in predisposition to liver cancer or other hepatic pathophysiologies.
Project description:We report the genome-wide map of nucleosome positions in the mouse liver, with emphasis on transcriptional start sites, CpG islands, Foxa2 binding sites, and their correlation with gene expression. Despite the heterogeneity of liver tissue, we could clearly discern the nucleosome pattern of the predominant liver cell, the hepatocyte. By analyzing nucleosome occupancy and the distributions of heterochromatin protein 1 (Hp1), CBP, and p300 in Foxa1/2-deficient livers we find, surprisingly, that the maintenance of nucleosome position and chromatin structure surrounding Foxa2 binding sites is independent of Foxa1/2. Examination of nucleosome map and Foxa2 binding in the mouse liver.