During translation elongation, the ribosome ratchets along its mRNA template, incorporating each new amino acid and translocating from one codon to the next. The elongation cycle requires dramatic structural rearrangements of the ribosome. We show here that deep sequencing of ribosome-protected mRNA fragments reveals not only the position of each ribosome but also, unexpectedly, its particular stage of the elongation cycle. Sequencing reveals two distinct populations of ribosome footprints, 28-30 nucleotides and 20-22 nucleotides long, representing translating ribosomes in distinct states, differentially stabilized by specific elongation inhibitors. We find that the balance of small and large footprints varies by codon and is correlated with translation speed. The ability to visualize conformational changes in the ribosome during elongation, at single-codon resolution, provides a new way to study the detailed kinetics of translation and a new probe with which to identify the factors that affect each step in the elongation cycle. Overall design: Ribosome profiling, or sequencing of ribosome-protected mRNA fragments, in yeast. We assay ribosome footprint sizes and positions in three conditions: untreated yeast (3 replicates) and yeast treated with translation inhibitors cycloheximide (2 replicates) and anisomycin (2 biological replicates, one technical replicate). We also treat yeast with 3-aminotriazole to measure the effect of limited histidine tRNAs on ribosome footprint size and distribution (two treatment durations).
Distinct stages of the translation elongation cycle revealed by sequencing ribosome-protected mRNA fragments.
Cell line, Treatment, Subject
View SamplesWe report here senescent changes in the structure and organization of the mucociliary pseudostratified epithelium of the mouse trachea and the main stem bronchi. We confirm previous reports of the graduate appearance of age-related, gland-like structures (ARGLS) in the submucosa, espeically in the intercartilage regions and carina. Immunohistochemistry shows these structures contain ciliated and secretory cells and Krt5+ basal cells, but not the myoepithelial cells or ciliated ducts typical of normal submucosal glands. Data suggests they arise de novo by budding from teh surface epithelium rather than by delayted growth of small or cryptic submucosal glands. In old mice the surface epithelium contains fewer cells per unit length than in young mice and the proportion of Krt5+, p63+ basal cells is reduced in both males and females. However, there appears to be no significant difference in the ability of basal stem cells isolated from individual young and old mice to form clonal tracheospheres in culture or in the ability of the pithelium to repair after damage by inhaled sulfur dioxide. Gene expression analysis by Affymetrix microarray and quantitative PCR, as well as immunohistochemistry and flow sorting studies, are consistent with low-grade chronic inflammation in the tracheas of old versus young mice. The significance of these changes for ARGL formation are not clear since several treatments that induce acute inflammation in young mice did not result in budding of the surface epithelium.
Age-related changes in the cellular composition and epithelial organization of the mouse trachea.
Sex, Age, Specimen part
View SamplesLong term exposure to incretin hormones is known to have salutory effects on beta cell function and viability. While short-term cAMP induction is known to have a signature CREB-CRTC target gene response, the long-term effects of cAMP on beta cell gene expression are less well understood.
mTOR links incretin signaling to HIF induction in pancreatic beta cells.
Cell line, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
BMP signaling and cellular dynamics during regeneration of airway epithelium from basal progenitors.
Sex, Specimen part, Treatment
View SamplesThe conducting airway epithelium of the rodent and human lung is made up of about equal proportions of ciliated and secretory cells. In addition, in regions where the epithelium is pseudostratfied, ~30% of the epithelium consists of undifferentiated basal cells (BCs). Evidence suggests that these BCs are multipotent stem cells that can self renew over the long term and give rise to both ciliated and secretory lineages. The goal of this project is to identify cellular and molecular mechanisms by which the basal cells normally maintain the epithelium and repair it after injury.
BMP signaling and cellular dynamics during regeneration of airway epithelium from basal progenitors.
Specimen part, Treatment
View SamplesThe conducting airway epithelium of the rodent and human lung is underlaid by mesenchymal cells that include vasculature, smooth muscle, fibroblasts and cartilage. The goal of this project is to identify cellular and molecular changes in the mesenchyme after injury to the epithelium by exposure to SO2 and which may participate in repair of the epithelium
BMP signaling and cellular dynamics during regeneration of airway epithelium from basal progenitors.
Sex, Specimen part, Treatment
View SamplesDuring fasting, increases in circulating pancreatic glucagon maintain glucose balance by up-regulating hepatic gluconeogenesis. Triggering of the cAMP pathway stimulates the gluconeogenic program through the phosphorylation of CREB and via the de-phosphorylation of the CREB coactivator CRTC2. Hormonal and nutrient signals are also thought to modulate gluconeogenic genes by promoting epigenetic changes that facilitate assembly of the transcriptional machinery, although the nature of these modifications is unclear. Here we show that histone H3 acetylation at Lys 9 (H3K9Ac) is elevated over gluconeogenic genes during fasting and in diabetes, where it contributes to increases in hepatic glucose production. Following its dephosphorylation, CRTC2 promoted increases in H3K9Ac by mediating the recruitment of the lysine acetyltransferase 2B (KAT2B) and WD repeat-containing protein 5 (WDR5), a core subunit of histone methyltransferase (HMT) complexes. In turn, KAT2B and WDR5 stimulated the gluconeogenic program through a self-reinforcing cycle whereby increases in H3K9Ac further potentiated CRTC2 occupancy at CREB binding sites. Breaking this cycle, by depletion of KAT2B or WDR5, decreased gluconeogenic gene expression. As administration of a small molecule KAT2B antagonist lowered circulating blood glucose concentrations in insulin resistance, our results demonstrate how this enzyme may be a useful target for diabetes treatment.
Glucagon regulates gluconeogenesis through KAT2B- and WDR5-mediated epigenetic effects.
Sex, Age, Specimen part
View SamplesEpithelial basal cells (BCs) are an important stem cell population of the airways. We purified BCs from a KRT5-GFP transgenic mouse line and used Affymetrix arrays to compare there gene expression to that of non-BC epithelium.
Basal cells as stem cells of the mouse trachea and human airway epithelium.
Specimen part, Cell line
View SamplesToca 511 is a modified Retroviral Replicating Vector based on Moloney g-retrovirus with an amphotropic envelope. As an investigational cancer treatment, Toca 511 preferentially infects cancer cells without direct cell lysis and encodes an enhanced yeast cytosine deaminase that converts the antifungal drug 5-fluorocytosine to the anticancer drug, 5-fluorouracil. A panel of established human cancers cell lines, derived from glioblastoma, colon, and breast cancer tissue was used to evaluate parameters critical for effective anticancer activity. As part of these analyses, we profiled relative mRNA levels across these cell lines via RNA sequencing. Overall design: mRNA expression profiles across nine human cancer cell lines.
Retroviral Replicating Vectors Deliver Cytosine Deaminase Leading to Targeted 5-Fluorouracil-Mediated Cytotoxicity in Multiple Human Cancer Types.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Evidence for multiple roles for grainyhead-like 2 in the establishment and maintenance of human mucociliary airway epithelium.[corrected].
Specimen part, Treatment
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