The chromatin of individual chromosomes is organized into chromosome territories (CTs) in the interphase nucleus. The spatial arrangement of CTs is non-random and evolutionarily conserved. The gene-dense and gene-poor CTs are positioned in the nuclear center and periphery, respectively. As candidates for key molecules involved in nuclear organization, we have investigated the nuclear actin-related proteins (Arps), which include the evolutionarily conserved actin-family together with conventional actin. We used a conditional knockout system with chicken DT40 cells to analyze the functions of the actin-related protein Arp6. Consistent with a previous identification of Arp6 in the SRCAP chromatin remodeling complex, the histone variant H2AZ was significantly decreased in the chromatin of Arp6-deficient cells. Most importantly, Arp6-deficient cells had impaired radial positioning of both gene-poor macrochromosome and gene-rich microchromosome CTs. A transcription microarray analysis of the cells suggests that the radial positioning of CTs impacts only a limited number of genes and plays an active role in repression, rather than in induction. As far as we know, this report is the first observation that an inner nuclear protein is required for the radial distribution of CTs, and will provide new insight into the mechanisms and physical significance of the positioning of CTs in the nucleus.
The actin family member Arp6 and the histone variant H2A.Z are required for spatial positioning of chromatin in chicken cell nuclei.
No sample metadata fields
View SamplesThe histone variant H2A.Z is evolutionarily conserved from yeast to vertebrates. H2A.Z regulates gene expression when localized to promoter region. Recently, we identified two genes encoding H2A.Z, H2A.Z-1 and H2A.Z-2 in vertebrate genome. However, it is not clear that both H2A.Z-1 and H2A.Z-2 were required for the function of H2A.Z in gene regulation. To address this issue, we generated the H2A.Z-1 and H2A.Z-2 double knock out (KO) cells in chicken DT40 cells. The expression pattern of H2A.Z-1 and H2A.Z-2 double KO cells was compared with WT cells to characterize the genes regulated by H2A.Z-1 and H2A.Z-2.
The actin family member Arp6 and the histone variant H2A.Z are required for spatial positioning of chromatin in chicken cell nuclei.
Specimen part, Cell line
View SamplesPersistent colonization of the gastric mucosa by Helicobacter pylori (Hp) elicits chronic inflammation and aberrant epithelial cell proliferation, which increases the risk of gastric cancer. We examined the ability of microRNAs to modulate gastric cell proliferation in response to persistent Hp infection and found that epigenetic silencing of miR-210 plays a key role in gastric disease progression. Importantly, DNA methylation of the miR-210 gene was increased in Hp-positive human gastric biopsies as compared to Hp-negative controls. Moreover silencing of miR-210 in gastric epithelial cells promoted proliferation. We identified STMN1 and DIMT1 as miR-210 target genes and demonstrated that inhibition of miR-210 expression augmented cell proliferation by activating STMN1 and DIMT1. Together, our results highlight inflammation-induced epigenetic silencing of miR-210 as a mechanism of induction of chronic gastric diseases, including cancer, during Hp infection.
Epigenetic silencing of miR-210 increases the proliferation of gastric epithelium during chronic Helicobacter pylori infection.
Cell line
View SamplesMediator complex has been known as pivotal regulator of RNA polymerase II. Mediator complex has two CDK subunits in vertebrates, named CDK8 and CDK19. To elucidate functional difference between CDK8 and CDK19 in human cell, we employ siRNA mediate knockdown assay using HeLa S3 cell line. According to this assay these CDKs possess highly redundancy in HeLa S3 cell transcription regulation mechanism but in several genes, each CDK shows gene specific regulatory function.
Identification of target genes for the CDK subunits of the Mediator complex.
Cell line
View SamplesMediator complex has been known as pivotal regulator of RNA polymerase II. Mediator complex has two CDK subunits in vertebrates, named CDK8 and CDK19. To elucidate functional difference between CDK8 and CDK19 in human cell, we employ siRNA mediate knockdown assay using HeLa S3 cell line. According to this assay these CDKs possess highly redundancy in HeLa S3 cell transcription regulation mechanism but in several genes, each CDK shows gene specific regulatory function.
Mediator complex recruits epigenetic regulators via its two cyclin-dependent kinase subunits to repress transcription of immune response genes.
Cell line
View SamplesWe have previously showed that whey protein hydrolysate (WPH) causes a greater increase in muscle protein synthesis than an identical composition of amino acids mixture does. The present study was conducted to investigate a comparative effect of WPH on gene expression. Male Sprague-Dawley rats subjected to a 2-h swimming exercise were administered either a carbohydrate-amino acid diet or a carbohydrate-WPH diet immediately after exercise. One hour after exercise, epitrochlearis muscle mRNA was sampled and subjected to DNA microarray analysis. As a result, ingestion of WPH altered 189 genes in considering the false discovery rate. Among the upregulated genes, 8 Gene Ontology (GO) terms were enriched, which included key elements in muscle repair after exercise such as Cd24, Ccl2, Ccl7 and Cxcl1. On the other hand, 9 GO terms were enriched in the gene sets downregulated by ingestion of WPH and these GO terms fell into 2 clusters, regulation of ATPase activity, and immune response. Furthermore, we found that WPH activate the 2 upstream proteins, extracellular signal-regulated kinase 1/2 (ERK1/2) and hypoxia-inducible factor-1 (HIF-1), which may act as key factors for regulation of gene expression. These results suggest that ingestion of WPH, compared to an identical composition of amino acid mixture, induces greater changes in the after-exercise gene expression profile via activation of the proteins, ERK1/2 and HIF-1.
Post-exercise impact of ingested whey protein hydrolysate on gene expression profiles in rat skeletal muscle: activation of extracellular signal-regulated kinase 1/2 and hypoxia-inducible factor-1α.
Sex, Age, Specimen part, Treatment
View SamplesJdp2 is a member of the AP-1 family and suppresses histone acetyltransferase activity. We used microarrays to examine the gene expression pattern of neutrophil form Jdp2-/- mice.
The transcription factor Jdp2 controls bone homeostasis and antibacterial immunity by regulating osteoclast and neutrophil differentiation.
Specimen part
View SamplesSpiroplasma (Mollicutes) is one of the heritable bacterial endosymbionts of Drosophila species. Several strains like S. poulsonii manipulate host reproduction in a selfish manner. When females of D. melanogaster are infected with natural S. poulsonii strain MSRO (melanogaster sex ratio organism), only male offspring are killed during embryogenesis, and this phenomenon is called male-killing. To understand the molecular mechanism of male-killing, we compared gene expression profiles between MSRO-infected and uninfected embryos of D. melanogaster by using RNA-sequencing (RNA-seq). For embryonic sexing, we employed a transgenic reporter strain Sex-lethal (Sxl)-Pe-EGFP, which expresses GFP only in females. We collected female and male embryos at stage 10-11, when abnormal apoptosis associated with male-killing starts to occur in male progenies. For each sample, we analyzed three biological replicates.
Male-killing symbiont damages host's dosage-compensated sex chromosome to induce embryonic apoptosis.
No sample metadata fields
View SamplesThe CCR4-NOT complex, bearing poly(A) deadenylation activity, is a highly conserved regulator that is involved in biological control; however its action mechanisms and physiological targets remain unclear. Using genetic deletion of the CNOT3 subunit of this complex in early B cell progenitors, we show that CNOT3 plays a critical role in pro- to pre-B cell transition. CNOT3 participated in controlling germline transcription, compaction of the immunoglobulin heavy chain (Igh) locus, and Igh rearrangement, and in destabilizing tumor suppressor p53 mRNA. Moreover, by genetic ablation of p53 or introduction of pre-rearranged Igh transgene, the B cell developmental defect in the Cnot3 knockout background could be partly rescued, suggesting that CCR4-NOT complex exerts critical control in B cell differentiation processes by co-utilizing transcriptional and post-transcriptional mechanisms. Overall design: Pro-B cells mRNA profiles of Mb1(cre/+) and Cnot3(fl/fl)Mb1(cre/+) mice were generated by deep sequencing using Illumina HiSeq 1500
CNOT3 contributes to early B cell development by controlling Igh rearrangement and p53 mRNA stability.
No sample metadata fields
View SamplesBackground: ETV6/RUNX1 (E/R) (also known as TEL/AML1) is the most frequent gene fusion in childhood acute lymphoblastic leukemia (ALL) and also most likely the crucial factor for disease initiation, whereas its role in leukemia propagation and maintenance remains largely elusive. To address this issue we performed a shRNA-mediated knock-down (KD) of the E/R fusion gene and investigated the ensuing consequences on genome-wide gene expression patterns and deducible regulatory functions in two E/R-positive leukemic cell lines. Findings: Microarray analyses identified 777 genes whose expression was substantially altered. Although approximately equal proportions were either up- (KD-UP) or down-regulated (KD-DOWN), the effects on biological processes and pathways differed considerably. The E/R KD-DOWN set was significantly enriched for genes included in the cell activation, immune response, apoptosis, signal transduction and development and differentiation categories, whereas in the E/R KD-UP set only the PI3K/AKT/mTOR signaling and hematopoietic stem cells categories became evident. Comparable expression signatures obtained from primary E/R-positive ALL samples underline the relevance of these pathways and molecular functions. We also validated six differentially expressed genes representing the categories stem cell properties, B-cell differentiation, immune response, cell adhesion and DNA damage with RT-qPCR. Conclusion: The results of our analyses provide the first preliminary evidence that the continuous expression of the E/R fusion gene interferes with regular B-cell development by repressing key functions that are necessary under physiological circumstances. E/R may thus constitute also the essential driving force for the propagation and maintenance of the leukemic process irrespective of potential consequences of associated secondary changes. Finally, these findings may also provide a valuable source of potentially attractive therapeutic targets.
The leukemia-specific fusion gene ETV6/RUNX1 perturbs distinct key biological functions primarily by gene repression.
Cell line, Treatment
View Samples