Duplication of eukaryotic genomes during S phase is coordinated in space and time. In order to identify zones of initiation and cell-type as well as gender-specific plasticity of DNA replication, we profiled replication timing, histone acetylation and transcription throughout the Drosophila genome. We observed two waves of replication initiation with many distinct zones firing in early and multiple, less defined peaks at the end of S phase, suggesting that initiation becomes more promiscuous at the end of S phase. A comparison of different cell types revealed widespread plasticity of replication timing on autosomes. Most occur in large regions but only half coincide with local differences in transcription. In contrast to confined autosomal differences, a global shift in replication timing occurs throughout the single male X chromosome. Unlike in females, the dosage compensated X chromosome replicates almost exclusively early. This difference occurs at sites which are not transcriptionally hyperactivated, but show increased acetylation of lysine 16 of histone H4. This suggests a transcription-independent, yet chromosome-wide process related to chromatin. Importantly, H4K16ac is also enriched at initiation zones as well as early replicating regions on autosomes during S phase. Together, our data reveal novel organizational principles of DNA replication of the Drosophila genome and imply chromatin structure as a determinant of replication timing locally and chromosome-wide.
Chromatin state marks cell-type- and gender-specific replication of the Drosophila genome.
Sex
View SamplesThe replication of a genomic region during S-phase can be highly dynamic between cell types that differ in transcriptome and epigenome. Replication timing has been positively correlated with several histone modifications that occur at active genes, while repressive histone modifications mark late replicating regions. This raises the question if chromatin modulates the initiating events of replication. To gain insights into this question we have studied the function of heterochromatin protein 1 (HP1), a reader of to the repressive histone lysine 9 methylation of H3, in genome-wide organization of replication. Cells with reduced levels of HP1 show an advanced replication timing of centromeric repeats in agreement with the model that repressive chromatin mediates the very late replication of large clusters of constitutive heterochromatin. Surprisingly however regions with high levels of interspersed repeats on the chromosomal arms in particular on chromosome 4 and in pericentromeric regions of chromosome 2 behave differently. Here loss of HP1 results in delayed replication timing. The fact that these regions are bound by HP1 suggests a direct effect. Thus while HP1 mediates very late replication of centromeric DNA it is also required for early replication of autosomal regions with high levels of repeats. This observation of opposing functions of HP1 suggests a model where repeat inactivation on autosomes is required for proper activation of origins of replication that fire early, while HP1 mediated repression at constitutive heterochromatin is required to ensure replication of centromeric repeats at the end of S phase.
Heterochromatin protein 1 (HP1) modulates replication timing of the Drosophila genome.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Molecular pathogenesis of post-transplant acute kidney injury: assessment of whole-genome mRNA and miRNA profiles.
Specimen part
View Samples18 zero-hour and 18 selected post-transplant (Tx) biopsy samples from 18 kidney allografts (8 acute kidney injury (AKI), 10 PBx - protocol biopsies - controls) were analyzed by using the Affymetrix GeneChip Human Gene 2.0 ST Array.
Molecular biomarker candidates of acute kidney injury in zero-hour renal transplant needle biopsies.
Specimen part
View SamplesRelapse, associated with therapy resistance, is a major clinical problem in acute myeloid leukemia (AML), yet little is known about the underlying molecular mechanisms. Using genome wide gene expression profiling on 11 paired samples from diagnosis and relapse, we show that the expression of a substantial number of genes was altered in a highly consistent manner between these disease stages. Furthermore, the relapse associated gene expression profile was significantly enriched for leukemia stem cell (LSC) genes, indicating that recurring AML is characterized by increased stemness, and supporting the concept that it is due to the outgrowth of chemotherapy resistant LSCs.
A gene expression profile associated with relapse of cytogenetically normal acute myeloid leukemia is enriched for leukemia stem cell genes.
Sex, Age
View SamplesObesity is strongly associated with the metabolic syndrome, a compilation of risk factors that predispose individuals to the development of cardiometabolic disease (CMD), i.e. cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). Controlling or preventing the worldwide epidemic of metabolic syndrome requires novel interventions to address this substantial health challenge. The objective of this study was the identification of potential new targets for the simultaneous prevention and treatment of insulin resistance and atherosclerosis, conditions that underlie T2DM and CVD, respectively. Therefore, we used an unbiased bioinformatics approach to identify molecules that are upregulated in both conditions by combining data from two microarray experiments and two meta-analyses. In the microarray experiments we compared gene expression in white adipose tissue (WAT) of obese mice as well as aortae of obese and atherosclerotic mice to respective lean controls. Furthermore, we performed a meta-analysis of published microarrays investigating atherosclerotic vessels and included a published meta-analysis on T2DM into our analyses. We obtained a pool of thirty-four genes that were upregulated in 3 out of the 4 underlying databases. These included well-known as well as novel crucial molecules for treatment of T2DM and CVD. Macrophage metalloelastase 12 (MMP12) was found highly ranked in all analyses and, therefore, chosen for further validation. Analyses of visceral and subcutaneous white adipose tissue from obese compared to lean mice and humans convincingly confirmed the up-regulation of MMP12 in obesity at mRNA, protein and, of note, activity levels. In conclusion, by this unbiased approach an interesting pool of potential molecular targets or biomarkers for treatment and prevention of CMD was identified with MMP12 being confirmed on multiple levels.
Identification of matrix metalloproteinase-12 as a candidate molecule for prevention and treatment of cardiometabolic disease.
Specimen part
View SamplesAdipose tissue inflammation and atherosclerosis are the main mechanisms behind type 2 diabetes and cardiovascular disease respectively, the major risks associated with the metabolic syndrome. Studies considering more than single factors behind the complexity of the metabolic syndrome are valuable to achieve a better and wider understanding of the metabolic syndrome. In this study common dysregulated pathways between adipose tissue inflammation and atherosclerosis were identified using two different bioinformatic tools to perform pathway analysis. First, we run a gene set enrichment analysis utilizing with data from two microarray experiments done with gonadal white adipose tissue and atherosclerotic aorta. Once the common dysregulated pathways between both tissues were identify, the inflammatory response and the oxidative phosphorylation pathways from the Hallmark geneset were selected to conduct a deeper checkup at the single gene level of these pathways. Second, we carried out a pathway analysis validation with the Panther software combining the microarray data with a published type 2 diabetes mellitus metanalysis and cardiovascular disease metanalysis which included human data. In conclusion, this study provides worthwhile data pointing out and describing several dysregulated and common pathways in adipose tissue inflammation and atherosclerotic aorta with a potential implication in the pathogenesis of type 2 diabetes and atherosclerosis.
Common dysregulated pathways in obese adipose tissue and atherosclerosis.
Specimen part
View SamplesBackground and aims: The transcription factor Stat3 has been considered to promote progression and metastasis of intestinal cancers.
Stat3 is a negative regulator of intestinal tumor progression in Apc(Min) mice.
Sex, Specimen part
View SamplesMyocardial left ventricular biopsies from male patients (n=6) with isolated aortic stenosis and pronounced left ventricular hypertrophy undergoing aortic valve replacement were harvested either from hearts with normal ejection fraction (EF,>50%) or with low EF (<30%). Biopsies were further obtained from non-hypertrophied hearts with normal EF (>60%) from coronary artery disease patients undergoing coronary artery bypass graft surgery (n=3). Total RNA isolated from biopsies was analyzed using Affymetrix HG-U133A and U133B GeneChip sets.
No associated publication
Sex, Specimen part, Disease, Disease stage
View SamplesAim of this project was the evaluation of the effect of flushing (intraportal and intraoperative) hepatic allografts with tacrolimus before transplantation. Group A was administered tacrolimus, 20ng/ml in 1500ml albumin solution; and Group B was administered only albumin solution. Wedge biopsie of the allograft were harvested after 15 min flushing time and the gene expression profile were determined.
Effect of intraportal infusion of tacrolimus on ischaemic reperfusion injury in orthotopic liver transplantation: a randomized controlled trial.
Specimen part, Treatment
View Samples