Project description:RUNX2 is a transcription factor that is first expressed in early osteoblast-lineage cells and represents a primary determinant of osteoblastogenesis. While numerous target genes are regulated by RUNX2, little is known of sites on the genome occupied by RUNX2 or of the gene networks that are controlled by these sites. To explore this, we conducted a genome-wide analysis of the RUNX2 cistrome in both pre-osteoblastic MC3T3-E1 cells (POB) and their mature osteoblast progeny (OB), characterized the two cistromes and assessed their relationship to changes in gene expression. We found that although RUNX2 was widely bound to the genome in POB cells, this binding profile was reduced upon differentiation to OBs. Numerous sites were lost upon differentiation, new sites were also gained; many sites remained common to both cell states. Additional features were identified as well including location relative to potential target genes, abundance with respect to single genes, the frequent presence of a consensus TGTGGT RUNX2 binding motif, co-occupancy by C/EBPβ and the presence of a typical epigenetic histone enhancer signature. This signature was changed quantitatively following differentiation. While RUNX2 binding sites were associated extensively with adjacent genes, the distal nature of the majority of these sites prevented assessment of whether they represented direct targets of RUNX2 action. Changes in gene expression, however, revealed an abundance of genes that contained RUNX2 binding sites and were regulated in concert. These studies establish a basis for further analysis of the role of RUNX2 activity and its function during osteoblast lineage maturation. RNA was isolated and applied to gene expression microarrays in undifferentiated MC3T3-E1 cells as well as post 15 day osteogenic differentiation MC3T3-E1 cells. The samples were completed in biological triplicate.
Project description:The biological effects of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) on osteoblast differentiation and function differ significantly depending upon the cellular state of maturation. To explore this phenomenon mechanistically, we examined the impact of 1,25(OH)2D3 on the transcriptomes of both pre-osteoblastic (POBs) and differentiated osteoblastic (OBs) MC3T3-E1 cells, and assessed localization of the vitamin D receptor (VDR) at sites of action on a genome-scale using ChIP-seq analysis. We observed that the 1,25(OH)2D3-induced transcriptomes of POBs and OBs were quantitatively and qualitatively different, supporting not only the altered biology observed but the potential for a change in VDR interaction at the genome as well. This idea was confirmed through discovery that VDR cistromes in POBs and OBs were also strikingly different. Depletion of VDR binding sites in OBs, due in part to reduced VDR expression, was the likely cause of the loss of VDR-target gene interaction. Continued novel regulation by 1,25(OH)2D3, however, suggested that factors in addition to the VDR might also be involved. Accordingly, we show that transcriptomic modifications are also accompanied by changes in genome binding of the master osteoblast regulator RUNX2 and the chromatin remodeler C/EBPβ. Importantly, genome occupancy was also highlighted by the presence of epigenetic enhancer signatures which were selectively changed in response to both differentiation and 1,25(OH)2D3. The impact of VDR, RUNX2, and C/EBPβ on osteoblast differentiation is exemplified by their actions at the Runx2 and Sp7 gene loci. We conclude that each of these mechanisms may contribute to the diverse actions of 1,25(OH)2D3 on differentiating osteoblasts. RNA was isolated and applied to gene expression microarrays in undifferentiated MC3T3-E1 cells as well as post 15 day osteogenic differentiation MC3T3-E1 cells, which were treated for 24 hours with 10-7M 1,25(OH)2D3. For the vehicle matched samples, please refer to study GSE41955. The samples were completed in biological triplicate.
Project description:Investigation on expression levels of normal tissue from prostate cancer patients on locus 8q24. 3 chips with 3 arrays each study, using 3 pairs of normal vs. tumor tissue and 3 replicates of the same sample. Each chip contained one pair of normal vs. tumor and one copy of the repeated sample.
Project description:Investigation on expression levels of normal tissue from prostate cancer patients on locus 8q24. The region chr8:127640000-129120000 is tiled with 60 nt probes at 10 nt interval (hg18) 7 chip study, using 7 independent samples.
Project description:Investigation on expression levels of normal tissue from prostate cancer patients on locus 8q24. The region chr8:127640000-129120000 is tiled with isothermal probes (hg17) 7 chip study, using 7 independent samples.
Project description:Embryonic stem cells (ESCs) and induced-pluripotent stem cells (iPSCs) self-renew and differentiate into an array of cell types in vitro and in vivo. A complex network of genetic and epigenetic pathways regulates the self-renewal and differentiation of these pluripotent cells, and the structure and covalent modifications of chromatin play a prominent role in this process. We examine nucleosome occupancy in mouse and human embryonic stem cells (ESCs), induced-pluripotent stem cells (iPSCs), and differentiated cell types using MNase-seq. To address variability inherent in this technique, we developed a bioinformatic approach that enabled the identification of regions of difference (RoD) in nucleosome occupancy between pluripotent and somatic cells. The majority of changes in nucleosomal signatures that occur in differentiation are reset during reprogramming. We conclude that changes in nucleosome occupancy are a hallmark of pluripotency and likely identify key regulatory regions that play a role in determining cell identity. A six chip study using total RNA recovered from three cell types with 2 replicates each
Project description:Investigation of whole genome gene expression level changes of LncRNAs in tumor tissues and paired non-tumor tissues in HBV-positive hapatocellular carcinoma. The different expression genes were further analysised. The human LncRNA microarray analysis of the 10 samples (5 non-tumor tissues and 5 paired tumor tissues) were completed. Total RNA from each sample was quantified using the NanoDrop ND-1000 and RNA integrity was assessed using standard denaturing agarose gel electrophoresis. Total RNA of each sample was used for labeling and array hybridization as the following steps: 1) Reverse transcription with by Invitrogen Superscript ds-cDNA synthesis kit; 2) ds-cDNA labeling with NimbleGen one-color DNA labeling kit; 3) Array hybridization using the NimbleGen Hybridization System and followed by washing with the NimbleGen wash buffer kit; 4) Array scanning using the Agilent Scanner G2505C. Scanned images (TIFF format) were then imported into NimbleScan software (version 2.5) for grid alignment and expression data analysis. Expression data were normalized through quantile normalization and the Robust Multichip Average (RMA) algorithm included in the NimbleScan software. The Probe level (*_norm_RMA.pair) files and mRNA level (*_RMA.calls) files were generated after normalization. All mRNAs level files were imported into Agilent GeneSpring GX software (version 11.5.1) for further analysis.mRNAs that at least 3 out of 6 samples have values greater than or equal to lower cut-off: 50.0 (“All Targets Value”) were chosen for further data analysis. Differentially expressed mRNAs were identified through Volcano Plot filtering. Pathway analysis and GO analysis were applied to determine the roles of these differentially expressed mRNAs played in these biological pathways or GO terms. Finally, Hierarchical Clustering was performed to show the distinguishable mRNAs expression pattern among samples.
Project description:This research investigates the molecular mechanisms of trait deterioration of two experimental lines of entamopathogenic nematodes, an inbred line (L5M) and its original parental line (OHB), created by sub-culturing different experimental lines of the nematode-bacterium complex over 20 passages in insect hosts. These lines differed in their virulence, heat tolerance and fecundity . Transcriptional profiles of the two experimental lines were determined and select differentially expressed genes were validated by quantitative PCR. Samples from four biological replicates each of the parental strain (OHB) and the laboratory strain (L5M) were hybridized to the custom H. bacteriophora arrays.