Gene expression analysis is a widely used and powerful method for investigating the transcriptional behavior of biological systems, for classifying cell states in disease and for many other purposes. Recent studies indicate that common assumptions currently embedded in experimental and analytical practices can lead to misinterpretation of global gene expression data. We discuss these assumptions and describe solutions that should minimize erroneous interpretation of gene expression data from multiple analysis platforms. Overall design: Polyadenylated RNA depleted of ribosomal content was used for preparation of two independent sequencing libraries (low-Myc & high-Myc). A panel of synthetic RNA''s was added to these populations, based on cell number.
Revisiting global gene expression analysis.
Specimen part, Cell line, Subject
View SamplesThe goal of this analysis was to investigate the targets of the influenza A host shutoff ribonuclease PA-X. We profiled the relative levels of cellular RNAs in cells infected with influenza A virus (A/PuertoRico/8/1934 H1N1) comparing wild-type and mutants that make reduced levels of PA-X and/or make a truncated and inactive PA-X. We also profiled relative RNA levels in cells overexpressing wild-type PA-X or a catalytically inactive mutant (D108A). Overall design: for extopic expression, PA-X (from the A/PuertoRico/8/1934 H1N1 (PR8) strain) was expressed in A549 cells using a doxycyline-inducible transgene for 18 hrs; for infection, A549 cells were infected with the wild-type PR8 strain or mutant strain that carried mutations that reduce PA-X production or activity for 15 hrs. rRNA deplete RNA was subjected to high-throughput sequencing
The Influenza A Virus Endoribonuclease PA-X Usurps Host mRNA Processing Machinery to Limit Host Gene Expression.
Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
c-Myc is a universal amplifier of expressed genes in lymphocytes and embryonic stem cells.
Specimen part
View SamplesThe c-Myc HLH-bZIP protein has been implicated in physiological or pathological growth, proliferation, apoptosis, metabolism and differentiation at the cellular, tissue or organismal levels via regulation of numerous target genes. In part due to the incomplete inventory and functional accounting of Mycs targets, no principle unifies Myc action. To relate the dynamics of Myc-binding with target expression and function in a system where Myc-levels are temporally and physiologically regulated, the transcriptomes and the genome-wide distributions of Myc, RNA polymerase II and chromatin modifications were compared during lymphocyte activation and in ES cells. A remarkably simple rule emerged from this quantitative analysis: Myc is not an on-off switch, but is a non-linear amplifier of expression, acting universally at active genes, except for immediate early genes that are strongly induced before Myc. This rule of Myc action explains the vast majority of Myc biology observed in literature.
c-Myc is a universal amplifier of expressed genes in lymphocytes and embryonic stem cells.
Specimen part
View SamplesMolecular adaptation of the intestinal mucosa occurs during microbial conventionalization to maintain a balanced immune response. However, the genetic regulation of such adaptation is obscure. Here, combined analysis of germ free and conventionalized mice revealed that the major molecular adaptations were initiated at day 4 of conventionalization with a strong induction of innate immune functions followed by stimulation of adaptive immune functions. We identified central regulatory genes and reconstructed a common regulatory network that appeared to be sufficient to regulate the dynamic adaptation of the intestinal mucosa to the colonizing microbiota. The majority of the genes within this regulatory network play roles in mucosal inflammatory diseases in mouse and human. We propose that the identified central regulatory network may serve as a genetic signature for control of intestinal homeostasis in healthy mice and may help to unravel the genetic basis of pathway dysregulation in human intestinal inflammatory diseases.
Temporal and spatial interplay of microbiota and intestinal mucosa drive establishment of immune homeostasis in conventionalized mice.
Sex, Specimen part
View SamplesSignaling through the thrombospondin-1 receptor CD47 broadly limits cell and tissue survival of stress, but the molecular mechanisms are incompletely understood. We now show that loss of CD47 permits sustained proliferation of primary murine endothelial cells and enables these cells to spontaneously reprogram to form multipotent embryoid bodies. c-Myc, Klf4, Oct4, and Sox2 expression is elevated in CD47-null endothelial cells, in several tissues of CD47- or thrombospondin-1-null mice, and in a human T cell line lacking CD47. CD47 knockdown acutely increases mRNA levels of c-Myc and other stem cell transcription factors in cells and in vivo, whereas CD47 ligation by thrombospondin-1 suppresses c-Myc expression. The inhibitory effects of increasing CD47 levels can be overcome by maintaining c-Myc expression and are absent in cells with dysregulated c-Myc. Thus, CD47 antagonists enable cell self-renewal and reprogramming by overcoming negative regulation of c-Myc and other stem cell transcription factors.
Thrombospondin-1 signaling through CD47 inhibits self-renewal by regulating c-Myc and other stem cell transcription factors.
Specimen part, Cell line
View SamplesThe MMSET (Multiple Myeloma SET domain) protein is overexpressed in multiple myeloma patients with the translocation t(4;14). Although studies have shown the involvement of MMSET/WHSC1 in development, its mode of action in the pathogenesis of multiple myeloma (MM) is largely unknown. We found that MMSET is a major regulator of chromatin structure and transcription in t(4;14) MM cells. High levels of MMSET correlate with an increase in lysine 36 methylation of histone H3 and a decrease in lysine 27 methylation across the genome, leading to a more open structural state of the chromatin. Loss of MMSET expression alters adhesion properties, suppresses growth and induces apoptosis in MM cells. Consequently, genes affected by high levels of MMSET are implicated in the p53 pathway, cell cycle regulation and integrin signaling. Regulation of many of these genes required functional histone methyl-transferase (HMT) activity of MMSET. These results implicate MMSET as a major epigenetic regulator in t(4;14)+ MM.
The MMSET histone methyl transferase switches global histone methylation and alters gene expression in t(4;14) multiple myeloma cells.
Disease, Cell line
View SamplesTo normalize transcriptome data we combined total RNA isolated from 10^6 resting or activated B cells with 1 µl of 1/10 dilution of Ambion’s ERCC RNA Spike-in Mix (92 mRNA standards). mRNA was then isolated and processed following Illumina’s RNA-seq protocol v2.
Global regulation of promoter melting in naive lymphocytes.
Specimen part, Cell line
View SamplesImmunosuppression is needed in HLA identical sibling renal transplantation. We conducted a tolerance trial in this patient cohort using Alemtuzumab induction, donor hematopoietic stem cells, tacrolimus/mycophenolate immunosuppression converted to sirolimus, planning complete drug withdrawal by 24 months post-transplantation. After an additional 12 months with no immunosuppression, normal biopsies and renal function, recipients were considered tolerant. Twenty recipients were enrolled. Of the first 10 (>36 months post-transplantation), 5 had immunosuppression successfully withdrawn for 16-36 months (tolerant), 2 had disease recurrence and 3 had subclinical rejection in protocol biopsies (non-tolerant). Microchimerism disappeared after 1 year, and CD4+CD25highCD127-FOXP3+ T cells and CD19+IgD/M+CD27- B cells increased to 5 years post-transplantation in both groups, whereas immune/inflammatory gene expression pathways in the peripheral blood and urine were differentially downregulated in tolerant compared to non-tolerant recipients. Therefore, in this HLA identical renal transplant tolerance trial, absent chimerism, Treg and Breg immunophenotypes were indistinguishable between tolerant and non-tolerant recipients, but global genomic changes indicating immunomodulation were observed only in tolerant recipients.
Genomic biomarkers correlate with HLA-identical renal transplant tolerance.
Specimen part, Time
View SamplesIn this study, we sought to establish the usefulness of LCM on cDNA microarray analysis. We reported that LCM samples improved the sensitivity of detection of differentially expressed genes over conventional bulk tissue analysis. We also provided the new information of chemokine and its receptor interaction within psoriatic lesional skin.
Combined use of laser capture microdissection and cDNA microarray analysis identifies locally expressed disease-related genes in focal regions of psoriasis vulgaris skin lesions.
Specimen part, Subject
View Samples