Alternative mRNA splicing is the main reason vast mammalian proteomic complexity can be achieved with a limited number of genes. Splicing is physically and functionally coupled to transcription and the rate of transcript elongation has a profound effect on splicing. As the nascent pre-mRNA emerges from transcribing RNA polymerase II (RNAPII), it is assembled into a messenger ribonucleoprotein (mRNP) particle that represents its functional form, and the composition of which determines the fate of the mature transcript4. However, factors that connect the transcribing polymerase with the mRNP particle and help integrate transcript elongation with mRNA splicing remain obscure. Here, we characterized the interactome of chromatin-associated mRNP particles and thereby identified Deleted in Breast Cancer 1 (DBC1) and a protein we named ZIRD. These proteins are subunits of a novel protein complex, named DBIRD, which binds directly to RNAPII. DBIRD regulates alternative splicing of a large set of exons embedded in A/T-rich DNA, and is present at the affected exons. RNAi-mediated DBIRD depletion results in region-specific decreases in transcript elongation, particularly across areas encompassing affected exons. These data indicate that DBIRD complex acts at the interface between mRNP particles and RNAPII, integrating transcript elongation with regulation of alternative splicing.
DBIRD complex integrates alternative mRNA splicing with RNA polymerase II transcript elongation.
Cell line
View SamplesConnections between RNA polymerase II (RNAPII) transcription stress, R-loops, and genome instability have been established however, the underlying mechanisms remain poorly understood. Here we used a mutant version of elongation factor TFIIS (TFIISmut) to specifically induce increased levels of RNAPII pausing, arrest, and/or backtracking in human cells. TFIISmut expression results in slower elongation rates, relative depletion of polymerases from the end of genes, and increased levels of stopped RNAPII. It affects mRNA splicing and termination as well. Remarkably, however, TFIISmut expression also dramatically increases R-loops, which may form at the anterior end of backtracked RNAPII and trigger genome instability, including DNA strand breaks. These results shed new light on the relationship between transcription stress and R-loops, and suggest that different classes of R-loops exist, potentially with distinct consequences for genome instability. Overall design: To study RNAPII backtracking and its effects in human cells, we used HEK293 TREX cells in which we overexpressed, under the control of a dox-promoter, a dominant negative form of TFIIS (TFIIS mut), an elongation factor necessary for stimulating RNAPII intrinsic cleavage activity. TFIISmut cells were maintained in the presence of Dox to ensure over-expression for 48 hours prior to harvest..
Elongation Factor TFIIS Prevents Transcription Stress and R-Loop Accumulation to Maintain Genome Stability.
Cell line, Treatment, Subject
View SamplesHuman CD4 positive T cells were isolated from cord blood using CD4 positive isolation kit from Dynal. Cells were activated with plate bound anti-CD3 and soluble anti-CD28 in presence (iTreg) or absence (Th0) of IL2, TGF beta and ATRA. The cells were harvested at 0, 0.5, 1, 2, 4, 6, 12, 24, 48, and 72 hours. Overall design: Comparing the gene expression in activated CD4+ cells and iTreg differentiated cells in human. 9 time points, 3 replicates for each time point.
Transcriptional Repressor HIC1 Contributes to Suppressive Function of Human Induced Regulatory T Cells.
Specimen part, Subject
View SamplesOur aim was to identify genes that were differentially expressed in microglia stimulated with Lipopolysaccharide, Luteolin, or both.
Luteolin triggers global changes in the microglial transcriptome leading to a unique anti-inflammatory and neuroprotective phenotype.
No sample metadata fields
View SamplesForced sustained swimming exercise at optimal speed enhances growth in many fish species, particularly through hypertrophy of the white skeletal muscle. The exact mechanism of this effect has not been resolved yet. To explore the mechanism, we first subjected wild-type zebrafish to an exercise protocol validated for exercise-enhanced growth, and showed that exercised zebrafish, which indeed showed enhanced growth, had higher cortisol levels than the non-exercised controls. A central role was therefore hypothesized for the steroid hormone cortisol acting through the Glucocorticoid receptor (Gr). Second, we subjected wild-type zebrafish and zebrafish with a mutant Gr to exercise at optimal, suboptimal and super-optimal speeds and compared them with non-exercised controls. Exercised zebrafish showed growth enhancement at all speeds, with highest growth at optimal speeds. In the Gr mutant fish, exercise resulted in growth enhancement similar to wild-type zebrafish, indicating that cortisol cannot be considered as a main determinant of exercise-enhanced growth. Finally, the transcriptome of white skeletal muscle tissue was analysed by RNA sequencing. The results of this analysis showed that in the muscle tissue of Gr mutant fish a lower number of genes is regulated by exercise than in wild-type fish (183 versus 351). A cluster of 36 genes was regulated by exercise in both wild-type and mutant fish. In this cluster, genes involved in transcriptional regulation and protein ubiquitination were overrepresented. Since growth was enhanced similarly in both wild-type fish and mutants, these processes may play an important role in exercise-enhanced growth. Overall design: Deep-sequencing transcriptome analysis of white muscle samples derived from wild-type (++) or glucocorticoid receptor (Gr) mutant (--) Danio rerio specimens that were exposed to either a resting (REST) or a swimming (UOPT) regimen: wild-type resting (REST++; n=3), Gr mutant resting (REST--; n=3), wild-type swimming (UOPT++; n=3), Gr mutant swimming (UOPT--; n=3).
Cortisol Acting Through the Glucocorticoid Receptor Is Not Involved in Exercise-Enhanced Growth, But Does Affect the White Skeletal Muscle Transcriptome in Zebrafish (<i>Danio rerio</i>).
Specimen part, Treatment, Subject
View SamplesNADPH-cytochrome P450 reductase (CPR) is important for the functions of many enzymes, such as microsomal cytochrome P450 (P450) monooxygenases and heme oxygenases. Two mouse models with deficient CPR expression in adults were recently generated in this laboratory: liver-Cpr-null (with liver-specific Cpr deletion) (Gu et al., J. Biol. Chem., 278, 2589525901, 2003) and Cpr-low (with reduced CPR expression in all organs examined) (Wu et al. J. Pharmacol. Expt. Ther. 312, 35-43, 2005). The phenotypes included a reduced serum cholesterol level and an induction of hepatic P450 in both models, and hepatomegaly and fatty liver in the liver-Cpr-null mouse alone. Our aim was to identify hepatic gene-expression changes related to these phenotypes. Cpr-lox mice, which have normal CPR expression (Wu et al., Genesis, 36, 177-181, 2003.), were used as the control in microarray analysis. A detailed analysis of the gene-expression changes in lipid metabolism and transport pathways revealed potential mechanisms, such as an increased activation of constitutive androstane receptor (CAR) and a decreased activation of peroxisomal proliferators activated receptor alpha (PPAR-gamma) by precursors of cholesterol biosynthesis, that underlie common changes (e.g., induction of multiple P450s and inhibition of genes for fatty acids metabolism) in response to CPR-loss in the two mouse models. Moreover, we also uncovered model-specific gene-expression changes, such as the induction of a lipid translocase (CD36 antigen) and the suppression of carnitine O-palmitoyltransferase 1 (CPT1a) and acyl-CoA synthetase long-chain family member 1 (Acsl1), that are potentially responsible for the severe hepatic lipidosis observed in liver-Cpr-null, but not Cpr-low mice.
Hepatic gene expression changes in mouse models with liver-specific deletion or global suppression of the NADPH-cytochrome P450 reductase gene. Mechanistic implications for the regulation of microsomal cytochrome P450 and the fatty liver phenotype.
No sample metadata fields
View SamplesAdenoid cystic carcinoma (ACC) is one of the most common malignancies that arise in the salivary glands, with an incidence of 4.5 per 1,000,000. It can also arise in glandular tissue closely related to salivary glands in the lacrimal gland, nasal passages and tracheobronchial tree, as well as in glands of the breast and vulva. At all of these sites, it is characterized by a distinctive histology of basaloid epithelial cells arranged in cribriform or tubular patterns, usually demonstrating abundant hyaline extracellular matrix secretion and some degree of myoepithelial differentiation. ACC is generally a slow-growing tumor characterized by a protracted clinical course, usually well over 5 years in duration, marked by regional recurrence, distant metastasis and/or spread along peripheral nerves. A recurrent chromosomal translocation, t(6;9)(q23;p21), has been identified in ACC, and recently it has been discovered that in a majority of ACC the MYB gene on chromosome 6 is fused to the 3 terminus of the NFIB gene on chromosome 9, creating a fusion gene product resulting in increased MYB-related transcriptional activation. Recently it has been determined that most cell lines with attribution of ACC derivation are either contaminants of other cell lines or do not have the characteristic MYB-NFIB translocation. Also, there are no animal models of this histologically and genetically defined tumor type. To address the paucity of experimental and pre-clinical models systems of ACC, we have for several years been establishing xenograft tumor lines from clinical samples of ACC. We describe our experience with these models and their characterization here.
Development and characterization of xenograft model systems for adenoid cystic carcinoma.
Specimen part
View SamplesTwist1 variants including wildtype Twist1, a non-phosphorylatable mutant Twist1/S42A and a phospho-mimicking mutant Twist1/S42D were expressed in 4T1 cells in which the endogenous Twist1 was depleted.
Akt/PKB-mediated phosphorylation of Twist1 promotes tumor metastasis via mediating cross-talk between PI3K/Akt and TGF-β signaling axes.
Specimen part
View SamplesWe found the PRC2 component EZH2 to be upregulated by the pathognomonic fusion oncogene EWS-FLI1 in Ewing tumors and mesenchymal stem cells (Richter GH et al., Proc Natl Acad Sci U S A. 2009;106:5324-9). Downregulation of EZH2 by RNA interference in Ewing tumor cell lines suppressed oncogenic transformation in vitro and in vivo. These data suggest that EZH2 might play a central role in Ewing Tumor pathology.
Epigenetic maintenance of stemness and malignancy in peripheral neuroectodermal tumors by EZH2.
No sample metadata fields
View SamplesExpansion for hematopoietic cells from umbilical cord blood is a strategy for use this cell source in clinic transplants, however, it is important to know about the genomic changes that can occur in expanded cells. In order to detect global expression profiles changes in hematopoietic stem and progenitors cells generated in vitro, we analyzed hematopoietics populations obtained by FACS in fresh from umbilical cord blood. HSC (fHSC) was defined as CD34+ CD38- CD71- CD45RA- Lin- and were cocultured with stromal cell line OP-9 plus FL, SCF, IL3, IL6, TPO, GMCSF and G-CSF by 7 days, after time we repurified HSC population by FACS using same immunophenotype (ivHSC). In other hand, fresh erythroid progenitors cells (fEPC) were identified as CD34+CD38+CD71+CD45RA- Lin- and fresh myeloid progenitors cells (fMPC) were identified as CD34+CD38+CD71-CD45RA+Lin-. In vitro progenitors cells (ivEPC and ivMPC) were obtained by culturing fHSC in Stemspan serum-free media plus SCF, TPO, IL6, FL and IL3 by 10 days, after time cells were repurified by FACS using same immunophenotype for fresh progenitors. In vitro generated cells were compared with their corresponding fresh population cells.
Functional Integrity and Gene Expression Profiles of Human Cord Blood-Derived Hematopoietic Stem and Progenitor Cells Generated In Vitro.
Specimen part
View Samples