Project description:The expression of a large proportion of the fission yeast genome changes periodically with the cell cycle. Several key transcription factors have been identified that regulate these oscillating and interdependent waves of gene expression. However, for a significant number of cell cycle-regulated genes the regulator(s) driving these oscillations remain unknown. Cbf11 and Cbf12, the fission yeast CSL transcription factors, have been implicated in the regulation of cell cycle progression, yet the details of their functioning are poorly understood. Using a combination of transcriptome profiling and genome-wide mapping of CSL-DNA interactions we have identified a comprehensive set of CSL-regulated genes. Our data indicate that Cbf11 and Cbf12 contribute directly and indirectly to the regulation of periodically expressed genes in fission yeast. We show that during S phase/cytokinesis Cbf11 directly activates the transcription of several periodic genes required in the cell to prevent catastrophic mitosis. In agreement with these findings, multiple aspects of cell cycle progression are perturbed when CSL cellular levels are genetically manipulated. We have identified Cbf11 as a novel cell cycle phase-specific activator of genes required for proper coordination of cell and nuclear division, and prevention of catastrophic mitosis in fission yeast.
Project description:In this study we explored the antiviral gene expression induced in the CNS of MHV-infected mice, by performing whole-genome expression profiling. Three different mouse strains (BALB/c, 129SvEv and 129SvEv IFNAR-/- mice), differing in their susceptibility to infection with MHV, were used.
Project description:Infection of cells with murine hepatitis virus strain A59 (MHV-A59) results in massive amounts of viral RNA within infected cells. When applying transcriptional profiling by means of microarray analysis, this could potentially cause problems since high amounts of viral RNA could in theory interfere with the analysis. Since coronavirus RNAs are polyadenylated, the viral RNAs are also amplified by oligo(dT) primers (a standard procedure when processing RNA samples for array hybridization). In this experiment we compared two different array platforms for the potential interference of viral RNA, using MHV-A59 infection of LR7 (murine fibroblasts) as a model.
Project description:We studied transcriptional responses of the fission yeast Schizosaccharomyces pombe to different intensities of H2O2 stress as well as two other oxidants: menadione sodium bisulfite and tert-butyl hydroperoxide. DNA microarrays were used to study the changes in expression profiles and the transcriptional regulation. We compare and contrast global expression and regulation of different intensities of H2O2 stress and different oxidants. The transcriptional response to low doses of H2O2 is very similar to menadione sodium bisulfite and the genes were controlled primarily by the transcription factor Pap1. The transcriptional response to medium and high doses of H2O2 is very similar to tert-butyl hydroperoxide and the genes were mostly regulated by the stress-activated MAP kinase Sty1p and the transcription factor Atf1p. We also compare global regulation of oxidative stress genes in fission and budding yeasts and discuss evolutionary implications.
Project description:Comparison of L5 DRG gene expression profiles at day 14 from gp120+ddC treated animals vs sham (SA + saline) treated animals.<br>This experiment is part of larger study, where the expression profiles of three disparate models of neuropathic pain (SNT, VZV infection and gp120+ddC) are compared in order to find genes that are responsible for mechanical hypersensitivity formation/maintenance.
Project description:Fission yeast cells belong to one of two specialized cell types, M or P. Specific environmental conditions trigger sexual differentiation, which leads to an internal program starting with pheromone signalling between M and P cells, followed by mating, meiosis and sporulation. The initial steps of this process are controlled by Ste11p, a master transcriptional regulator that activates the expression of cell type-specific genes (only expressed in either M or P cells) as well as genes expressed in both M and P cells. <br><br> Pheromone signalling is activated by Ste11p-dependent transcription, and in turn enhances some of this transcription in a positive feedback. To obtain a genome-wide view of Ste11p target genes, their cell-type specificity, and their dependence on pheromone, we used DNA microarrays along with different genetic and environmental manipulations of fission yeast cells.We directly compared the transcriptome of homothallic wild-type cells (h90 fus1) with that of ste11 delta mutants under conditions that induce sexual differentiation. To allow for indirect effects of the ste11 delta mutation, we took advantage of the fact that ectopic expression of ste11 can drive cells into sexual differentiation and therefore is expected to cause the expression of Ste11p targets. We thus defined Ste11p targets as those genes whose expression was significantly reduced in a ste11 delta mutant and significantly increased when ste11 is overexpressed in vegetative cells.<br> <br> This study looked at the effect of deletion or overexpression of ste11, and changes in gene expression after nitrogen starvation of h plus, h minus, h90fus1 and h90ste11 cells.
Project description:Microarray based CGH was conducted over a group of 29 strains of S. Enteritidis spanning different epidemiological periods in Uruguay, plus 6 other S. Enteritidis strains isolated from distant geographical regions. We also included 9 Salmonella enterica strains of other serovars isolated in Uruguay. A S. Enteritidis dispensable genome of 233 chromosomal genes and high extent of variation in virulence plasmid was found. Strains isolated before the epidemic show the highest genomic differences as compared with the PT4 reference strain. Comparison with the gene content of other serovars demonstrate extensive horizontal gene transfer between circulating strains beyond serovar definition. Our results show that the epidemic of S Enteritidis in Uruguay was produced by the introduction of strains closely related to PT4, and corroborate the extensive genetic homogeneity among S. Enteritidis isolates worldwide. Phage SE14 emerges as the only specific region for S. Enteritidis. Genetic differences detected in pre-epidemic strains, mainly associated with the absence of phage SE20, suggest that genetic features encoded in this phage may be related to particular epidemiological behavior.