Project description:Transcription profiling of fission yeast /yox1/ deletion and genome wide location analysis of Yox1p and Cdc10p transcription factors reveal a negative feedback interaction: /yox1 /is transcriptionally activated by MBF, and Yox1p in turn transcriptionally represses the MBF target genes (including /yox1 /itself).
Project description:In order to identify novel regulators of haematopoietic stem cell emergence in the mouse embryonic AGM region, 3 different types of gene expression comparisons were performed. In the first one, whole dorsal aortas from embryonic day (E) 11 embryos and E9 embryos were dissected, tissues from each time point were pooled and their expression profile compared (whole aorta (WA) E9 vs E11). 3 different pools/biological replicas were obtained for each time point, a dye swap was included in each experiment, a technical replicate was performed for each pool (including the dye swap) and 2 self-self hybridisation controls were included. In the second comparison, GFP+ cells were isolated by fluorescence-activated cell sorting from pooled E9 and E11 aortas from transgenic embryos that express GFP under the regulatory elements of the Ly-6A gene. We obtained one pool for each time point and compared their transcription profile (GFP E9 vs E11). This comparison also contained a dye swap and a technical replicate (also of the dye swap). In the third comparison, the E11 aorta was cut into 3 roughly equal parts. Pools were obtained of the middle region ("m") and the two outer regions, rostral and caudal, together ("r+c") and their expression profile compared (11AO m vs r+c). There was one pool of each population, and the experiment included a dye swap and a technical replicate (also of the dye swap) and one self-self hybridisation control. Isolated RNA was amplified by T7-mediated in vitro transcription, with one round for the first and the third comparison and two rounds for the second comparison (sorted GFP+ cells). Probes were labelled during the reverse transcription step. Within array normalisation was achieved with Lowess Smooth and between arrays with Z scores. ANOVA analysis identified differentially expressed genes and K means clustering was used to segregate them into upregulated and downregulated genes.
Project description:To understand how metabolic and nutritional factors governing adaptation to the host niche contribute to the virulence of Aspergillus fumigatus we compared transcriptomes of developmentally matched A.fumigatus isolates following laboratory culture or initiation of infection in the neutropenic murine lung.
Project description:The presence of Set2-mediated methylation of H3K36 (K36me) correlates with transcription frequency throughout the yeast genome. K36me targets the Rpd3S complex to deacetylate transcribed regions and suppress cryptic transcription initiation at certain genes. Here, using a genome-wide approach, we report that the Set2-Rpd3S pathway is generally required for controlling acetylation at coding regions. When using acetylation as a functional read-out for this pathway, we discovered that longer genes and, surprisingly, genes transcribed at lower frequency exhibit a stronger dependency. Moreover, a systematic screen using high resolution tiling microarrays allowed us to identify a group of genes that rely on Set2-Rpd3S to suppress spurious transcripts. Interestingly, most of these genes are within the group that depend the same pathway to maintain a hypo-acetylated state at coding regions. These data highlight the importance of using the functional readout of histone codes to define the roles of specific pathways.
Project description:Expression data from Kc167 cells under normal conditions. Used to assess expression levels of genes with ORC bound at promoter. Control experiments in support of our previous modencode submssion GSE17282. Kc167 cells were harvested from log phase gorwth. RNA extraction and hybridization on Affymetrix microarrays. Chromatin immunoprecipitation with IgG against TAP-ORC2 or control cells.
Project description:One major effect of PI3-kinase activation downstream of the serine/threonine kinase Akt is the phosphorylation of the transcription factor FOXO1 and its neutralization. FOXO1 has several ubiquitous targets genes in many cell types that control cell quiescence, oxydative stress or apoptosis. However, it has been demonstrated that FOXO1 also has specific targets depending of the cellular context. The role of FOXO1 to regulate specific genes in T lymphocytes has not been investigated yet. To examine this point, we used the CD4+ leukemia Jurkat T-cell line, in which the PI3K pathway is constitutively turned-on and FOXO1 transcriptional activity strongly repressed. These cells were transduced with lentiviruses coding for a constitutively active form of FOXO1 fused to GFP and having the three AKT phosphorylation sites mutated to alanine (FOXO1-AAA-GFP) to restore its transcriptional activity. GFP-transduced cells were used as a control and the gene activation levels in the two cell populations analyzed 48 hours post-infection.
Project description:Nucleosomes must be deacetylated behind elongating RNA polymerase II to prevent cryptic initiation of transcription within the coding region. RNA polymerase II signals for deacetylation through methylation of histone H3 lysine 36 (H3K36) which provides the recruitment signal for the Rpd3S deacetylase complex. Recognition of methyl-H3K36 by Rpd3S requires the chromodomain of its Eaf3 subunit. Paradoxically, Eaf3 is also a subunit of the NuA4 acetyltransferase complex yet NuA4 does not recognize methyl H3K36 nucleosomes. We found that methyl H3K36 nucleosome recognition by Rpd3S also requires the PHD domain of its Rco1 subunit. Thus, the coupled chromo and PHD domains of Rpd3S specifies recognition of the methyl H3K36 mark; demonstrating the first combinatorial domain requirement within a protein complex to read a specific histone code.
Project description:Determination of the genome-wide distribution of ORC by chromatin immunoprecipitation in the Drosophila Kc167 cell line at the beginning of S phase. Kc167 cells were arrested at the G1/S transition with hydroxyurea (HU). Goal was to test whether the ORC binding distribution remained the same between G1 and S. ChIP-Chip of ORC in HU compared to input genomic DNA. Biological Replicates: 1