Project description:Chlamydia pneumoniae, an obligate intracellular bacterium, causes pneumonia in humans and mice. Toll-like receptors and the key adaptor molecule MyD88 play a critical role in inducing immunity against this microorganism and are crucial to survive the infection. To explore the influence of MyD88 on induction of immune responses in vivo on a genome wide level, WT or MyD88-/- mice were infected with C. pneumoniae upon anesthesia and the pulmonary transcriptome was analyzed three days later by microarrays. We find that the infection induced the transcription of 360 genes and repressed 18 genes in WT mice. Of these, 221 genes were not or weakly induced in lungs of MyD88-/- mice. This cluster contains primarily genes encoding for chemokines, cytokines and other immune effector molecules. Genes induced by interferons were abundant in a cluster of 102 genes which were only partially MyD88-dependent. Interestingly, a set of 37 genes were induced more strongly in MyD88-/- mice and most of them are involved in the regulation of cellular replication. In summary, ex vivo analysis of the pulmonary transcriptome upon infection with C. pneumoniae demonstrated a major impact of MyD88 on inflammatory responses but not on interferon-type responses, and identified MyD88-independent genes involved in cellular replication Experiment Overall Design: Microarray analysis was performed in biological triplicates with RNA from individual mice derived from three independent infection experiments. Samples were lungs from wt and myd88 knock out mice, three days after Chlamydia pneumoniae or mock infection. Altogther 12 samples were analyzed on Affymetrix MOE430A arrays.
Project description:Chlamydia pneumoniae, an obligate intracellular bacterium, causes pneumonia in humans and mice. Toll-like receptors and the key adaptor molecule MyD88 play a critical role in inducing immunity against this microorganism and are crucial to survive the infection. To explore the influence of MyD88 on induction of immune responses in vivo on a genome wide level, WT or MyD88-/- mice were infected with C. pneumoniae upon anesthesia and the pulmonary transcriptome was analyzed three days later by microarrays. We find that the infection induced the transcription of 360 genes and repressed 18 genes in WT mice. Of these, 221 genes were not or weakly induced in lungs of MyD88-/- mice. This cluster contains primarily genes encoding for chemokines, cytokines and other immune effector molecules. Genes induced by interferons were abundant in a cluster of 102 genes which were only partially MyD88-dependent. Interestingly, a set of 37 genes were induced more strongly in MyD88-/- mice and most of them are involved in the regulation of cellular replication. In summary, ex vivo analysis of the pulmonary transcriptome upon infection with C. pneumoniae demonstrated a major impact of MyD88 on inflammatory responses but not on interferon-type responses, and identified MyD88-independent genes involved in cellular replication Keywords: lung, Chlamydia pneumoniae, mice, myd88, TLR, infection, knock out
Project description:Transcription profiling of lungs from wild type and MyD88 knockout mice infected with Chlamydia pneumoniae to explore the influence of MyD88 on induction of immune responses.
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:Infection with Chlamydia pneumoniae, a human respiratory pathogen, has been associated with various chronic diseases such as asthma, coronary heart disease and importantly atherosclerosis. Possibly because the pathogen can exist in a persistent form. TNF-a has been reported to induce chlamydial persitence in epithelial cell lines, however the mechanism of TNF-a-induced persistence has not been reported. Moreover, C. pneumoniae persistently infect human dendritic cells (DCs) and activate DCs to produce cytokines including TNF-a. Induction of chlamydial persistence by other cytokines such as IFN-g is known to be due to indoleamine 2,3-dioxygenase (IDO) activity. The present study therefore, investigated whether C. pneumoniae infection can induce IDO activity in dendritic cells, and whether the restriction of chlamydial growth in the DCs by TNF-a is IDO-dependent. Our data indicate that infection of DCs with C. pneumoniae resulted in the induction of IDO expression. Reporting on our use of anti-TNF-a antibody adalimumab and varying concentrations of TNF-a, we further demonstrate that IDO induction following infection of DCs with C. pneumoniae is TNF-a-dependent. The anti-chlamydial activity induced by TNF-a and the expression of chlamydial 16S rRNA gene, euo, groEL1, ftsk and tal genes was correlated with the induction of IDO. Addition of excess amounts of tryptophan to the DC cultures resulted in abrogation of the TNF-a-mediated chlamydial growth restriction. These findings suggest that infection of DCs by C. pneumoniae induces production of functional IDO, which subsequently causes depletion of tryptophan. This may represent a potential mechanism for DCs to restrict bacterial growth in chlamydial infections. Keywords: Chlamydia pneumoniae, Dendritic cells, TNF-a, Indoleamine 2,3-dioxygenase
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:BackgroundCopy number variation is an important dimension of genetic diversity and has implications in development and disease. As an important model organism, the mouse is a prime candidate for copy number variant (CNV) characterization, but this has yet to be completed for a large sample size. Here we report CNV analysis of publicly available, high-density microarray data files for 351 mouse tail samples, including 290 mice that had not been characterized for CNVs previously.ResultsWe found 9634 putative autosomal CNVs across the samples affecting 6.87% of the mouse reference genome. We find significant differences in the degree of CNV uniqueness (single sample occurrence) and the nature of CNV-gene overlap between wild-caught mice and classical laboratory strains. CNV-gene overlap was associated with lipid metabolism, pheromone response and olfaction compared to immunity, carbohydrate metabolism and amino-acid metabolism for wild-caught mice and classical laboratory strains, respectively. Using two subspecies of wild-caught Mus musculus, we identified putative CNVs unique to those subspecies and show this diversity is better captured by wild-derived laboratory strains than by the classical laboratory strains. A total of 9 genic copy number variable regions (CNVRs) were selected for experimental confirmation by droplet digital PCR (ddPCR).ConclusionThe analysis we present is a comprehensive, genome-wide analysis of CNVs in Mus musculus, which increases the number of known variants in the species and will accelerate the identification of novel variants in future studies.
Project description:BackgroundLong terminal repeat (LTR) retrotransposons make up a large fraction of the typical mammalian genome. They comprise about 8% of the human genome and approximately 10% of the mouse genome. On account of their abundance, LTR retrotransposons are believed to hold major significance for genome structure and function. Recent advances in genome sequencing of a variety of model organisms has provided an unprecedented opportunity to evaluate better the diversity of LTR retrotransposons resident in eukaryotic genomes.ResultsUsing a new data-mining program, LTR_STRUC, in conjunction with conventional techniques, we have mined the GenBank mouse (Mus musculus) database and the more complete Ensembl mouse dataset for LTR retrotransposons. We report here that the M. musculus genome contains at least 21 separate families of LTR retrotransposons; 13 of these families are described here for the first time.ConclusionsAll families of mouse LTR retrotransposons are members of the gypsy-like superfamily of retroviral-like elements. Several different families of unrelated non-autonomous elements were identified, suggesting that the evolution of non-autonomy may be a common event. High sequence similarity between several LTR retrotransposons identified in this study and those found in distantly-related species suggests that horizontal transfer has been a significant factor in the evolution of mouse LTR retrotransposons.
Project description:Here we report the expansion of the genetic code of Mus musculus with various unnatural amino acids including Nɛ-acetyl-lysine. Stable integration of transgenes encoding an engineered Nɛ-acetyl-lysyl-tRNA synthetase (AcKRS)/tRNAPyl pair into the mouse genome enables site-specific incorporation of unnatural amino acids into a target protein in response to the amber codon. We demonstrate temporal and spatial control of protein acetylation in various organs of the transgenic mouse using a recombinant green fluorescent protein (GFPuv) as a model protein. This strategy will provide a powerful tool for systematic in vivo study of cellular proteins in the most commonly used mammalian model organism for human physiology and disease.
Project description:House mice (Mus musculus) emit ultrasonic vocalizations (USVs), which are surprisingly complex and have features of bird song, but their functions are not well understood. Previous studies have reported mixed evidence on whether there are sex differences in USV emission, though vocalization rate or other features may depend upon whether potential receivers are of the same or opposite sex. We recorded the USVs of wild-derived adult house mice (F1 of wild-caught Mus musculus musculus), and we compared the vocalizations of males and females in response to a stimulus mouse of the same- or opposite-sex. To detect and quantify vocalizations, we used an algorithm that automatically detects USVs (Automatic Mouse Ultrasound Detector or A-MUD). We found high individual variation in USV emission rates (4 to 2083 elements/10 min trial) and a skewed distribution, with most mice (60%) emitting few (≤50) elements. We found no differences in the rates of calling between the sexes overall, but mice of both sexes emitted vocalizations at a higher rate and higher frequencies during opposite- compared to same-sex interactions. We also observed a trend toward higher amplitudes by males when presented with a male compared to a female stimulus. Our results suggest that mice modulate the rate and frequency of vocalizations depending upon the sex of potential receivers.