Project description:Several methicillin resistance (SCCmec) clusters characteristic of hospital-associated methicillin-resistant Staphylococcus aureus (MRSA) strains harbor the psm-mec locus. In addition to encoding the cytolysin, phenol-soluble modulin (PSM) mec, this locus has been attributed gene regulatory functions. Here we employed genome-wide transcriptional profiling to define the regulatory function of the psm-mec locus. The immune evasion factor protein A emerged as the primary conserved and strongly regulated target of psm-mec, an effect we show is mediated by the psm-mec RNA. Furthermore, the psm-mec locus exerted regulatory effects that were more moderate in extent and possibly mediated by the PSM-mec peptide. For example, expression of PSM-mec limited expression of mecA, thereby decreasing methicillin resistance. Our study shows that the psm-mec locus has a rare dual regulatory RNA and encoded cytolysin function, both with the potential to enhance MRSA virulence. Furthermore, our findings reveal a specific mechanism underscoring the recently emerging concept that S. aureus strains balance pronounced virulence and high expression of antibiotic resistance.
Project description:Neural circuits in the medial entorhinal cortex (MEC) encode an animal’s position and orientation in space. Within the MEC spatial representations, including grid and directional firing fields, have a laminar and dorsoventral organization that corresponds to a similar topography of neuronal connectivity and cellular properties. Yet, in part due to the challenges of integrating anatomical data at the resolution of cortical layers and borders, we know little about the molecular components underlying this organization. To address this we develop a new computational pipeline for high-throughput analysis and comparison of in situ hybridization (ISH) images at laminar resolution. We apply this pipeline to ISH data for over 16,000 genes in the Allen Brain Atlas and validate our analysis with RNA sequencing of MEC tissue from adult mice. We find that differential gene expression delineates the borders of the MEC with neighboring brain structures and reveals its laminar and dorsoventral organization. Our analysis identifies ion channel-, cell adhesion- and synapse-related genes as candidates for functional differentiation of MEC layers and for encoding of spatial information at different scales along the dorsoventral axis of the MEC. Our results support the hypothesis that differences in gene expression contribute to functional specialization of superficial layers of the MEC and dorsoventral organization of the scale of spatial representations.
Project description:Transcriptional profiling of Murine Embryonic Fibroblasts (MEFs) infected with Ad-MyD88 vs. Ad-GFP or mock infected. Three-condition experiment, Ad-MyD88 vs. Ad-GFP vs. Mock infected cells. Biological replicates: 3 Ad-MyD88, 3 Ad-GFP, 3 mock, independently grown and harvested. One replicate per array.
Project description:We identified PDK4 as a gene with adaptive transcriptional response to chemical stress. Although PDK4 is an energy resource regulator induced by starvation, expression of other fasting-inducible genes was unaffected, indicating additional physiological role of PDK4 for liver adaptation to the chemical stress. We used microarrays to determine genes with altered transcriptional level by PDK4 overexpression. Mice were infected with Ad-control (empty adenovirus vector) or Ad-PDK4 (PDK4 overexpressing adenovirus vector) at a dose of 10^9 PFU/mouse by tail vein injection. 3 days after the infection, mice were sacrificed for RNA preparation from the liver. Ad-control infected = 4, Ad-PDK4 infected = 3. Specimens from mice of each group were pooled, and 10 ug RNA from each pool was used for cRNA synthesis.
Project description:Transcriptional profiling of Bone-Marrow derived mouse Dendritic Cells (bmDCs) infected with Ad-MyD88 vs. Ad-GFP or mock infected Three-condition experiment, Ad-MyD88 vs. Ad-GFP vs. Mock infected cells. Biological replicates: 3 Ad-MyD88, 3 Ad-GFP, 3 mock, independently grown and harvested. One replicate per array.