Project description:We used microarrays to detail the global programme of gene expression of the mouse colon responses to Salmonella (SL1344 and SB1117) infection at the early phase (8 hours) and the late phase (4 days). We specifically examined the the differentillay gene expression profiles in mouse colon when it responded to pathogenic Salmonella stain SL1344 (with AvrA expression) or SB1117 (without AvrA expression).
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 used microarrays to detail the global programme of gene expression of the mouse colon responses to Salmonella (SL1344 and SB1117) infection at the early phase (8 hours) and the late phase (4 days). We specifically examined the the differentillay gene expression profiles in mouse colon when it responded to pathogenic Salmonella stain SL1344 (with AvrA expression) or SB1117 (without AvrA expression). Mice were infected with 1x107 CFU of samonella stains, SL1344 and SB1117 respectively (100µl suspension in HBSS) or treated with sterile HBSS (control) by oral gavage as previously described. At 8 hours and 4 days after infection, mice were sacrificed and RNA tissue samples from the intestinal tracts were removed for analysis.
Project description:Methoxyacetic acid (MAA) is the active metabolite of the widely used industrial chemical ethylene glycol monomethyl ether, an established testicular toxicant. MAA induces the degradation of testicular germ cells in association with changes in gene expression in both germ cells and Sertoli cells of the testis. This study investigates the impact of MAA on gene expression in testicular Leydig cells, which play a critical role in germ cell survival and male reproductive function. Cultured mouse TM3 Leydig cells were treated with MAA for 3, 8, and 24 h and global gene expression was monitored by microarray analysis. A total of 3,912 MAA-responsive genes were identified. Ingenuity Pathway analysis identified reproductive system disease, inflammatory disease and connective tissue disorder as the top biological functions affected by MAA. The MAA-responsive genes were classified into 1,366 early responders, 1,387 mid-responders, and 1,138 late responders, based on the time required for MAA to elicit a response. Analysis of enriched functional clusters for each subgroup identified 106 MAA early response genes involved in transcription regulation, including 32 genes associated with developmental processes and 60 DNA-binding proteins that responded to MAA rapidly but transiently, and which may contribute to the downstream effects of MAA seen for large numbers of mid and late response genes. Genes within the phosphatidylinositol/phospholipase C/calcium signaling pathway, whose activity is required for potentiation of nuclear receptor signaling by MAA, were also enriched in the set of early MAA response genes. These findings on the progressive changes in gene expression induced by MAA in Leydig cells may help elucidate the signaling pathways perturbed by this testicular toxicant and explain its mechanism of toxicity at the gene level.
Project description:The immune response against pathogens involves multiple cell state transitions and complex gene expression changes. Here we established an in vivo single-cell nascent RNA labeling sequencing method (scnasRNA-seq) and applied it to survey time-resolved RNA dynamics during immune response to acute enteric infection with Salmonella. We showed that detection of nascent RNA synthesis reflects more realistic information on cell activation and gene transcription than total RNA level. Interplay of nascent RNA synthesis and RNA degradation together modulate dynamics of total RNA. We found that bone marrow macrophages are first primed at very early stage upon Salmonella infection. In contrast, the innate immune response of macrophages in intestine is limited. Notably, intestinal CD8+ T cells and plasma cells are rapidly and specifically activated at early stage post infection. Intestinal late enterocytes quickly express MHC-I molecules and present Salmonella antigen to CD8+ T cells for their activation, serving as antigen presenting cells for initiation of adaptive immunity. Our findings unveil novel RNA control strategies of immune cells and dynamic time course of immune response activation upon Salmonella infection, challenging the doctrine boundary between innate immunity and adaptive immunity against bacterial infection.
Project description:The immune response against pathogens involves multiple cell state transitions and complex gene expression changes. Here we established an in vivo single-cell nascent RNA labeling sequencing method (scnasRNA-seq) and applied it to survey time-resolved RNA dynamics during immune response to acute enteric infection with Salmonella. We showed that detection of nascent RNA synthesis reflects more realistic information on cell activation and gene transcription than total RNA level. Interplay of nascent RNA synthesis and RNA degradation together modulate dynamics of total RNA. We found that bone marrow macrophages are first primed at very early stage upon Salmonella infection. In contrast, the innate immune response of macrophages in intestine is limited. Notably, intestinal CD8+ T cells and plasma cells are rapidly and specifically activated at early stage post infection. Intestinal late enterocytes quickly express MHC-I molecules and present Salmonella antigen to CD8+ T cells for their activation, serving as antigen presenting cells for initiation of adaptive immunity. Our findings unveil novel RNA control strategies of immune cells and dynamic time course of immune response activation upon Salmonella infection, challenging the doctrine boundary between innate immunity and adaptive immunity against bacterial infection.
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:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other