Human tumors often contain slowly proliferating cancer cells that resist treatment but we do not know precisely how these cells arise. We show that rapidly proliferating cancer cells can divide asymmetrically to produce slowly proliferating G0-like progeny that are enriched following chemotherapy in breast cancer patients. Asymmetric cancer cell division results from asymmetric suppression of AKT/PKB kinase signaling in one daughter cell during telophase of mitosis. Moreover, inhibition of AKT signaling with small molecule drugs can induce asymmetric cancer cell division and the production of slow proliferators. Cancer cells therefore appear to continuously flux between symmetric and asymmetric division depending on the precise state of their AKT signaling network. This model may have significant implications for understanding how tumors grow, evade treatment, and recur.
Asymmetric cancer cell division regulated by AKT.
Specimen part, Cell line
View SamplesLongevity mechanisms increase lifespan by counteracting the effects of aging. However, whether longevity mechanisms counteract the effects of aging continually throughout life, or whether they act during specific periods of life, preventing changes that precede mortality is unclear. Here, we uncover transcriptional drift, a phenomenon that describes how aging causes genes within functional groups to change expression in opposing directions. These changes cause a transcriptome-wide loss in mRNA stoichiometry and loss of co-expression patterns in aging animals, as compared to young adults. Using Caenorhabditis elegans as a model, we show that extending lifespan by inhibiting serotonergic signals by the antidepressant mianserin attenuates transcriptional drift, allowing the preservation of a younger transcriptome into an older age. Our data are consistent with a model in which inhibition of serotonergic signals slows age-dependent physiological decline and the associated rise in mortality levels exclusively in young adults, thereby postponing the onset of major mortality. Overall design: In this study set out to measure aging in the transcriptome by determining drift-variance changes with age in C.elegans. We set up three different cohorts of water or mianserin treated animals. The title of each cohort indicates the treatment (e.g. h2o or mia), the concentration (mia2, mia10, mia50), the day when the treatment was started (e.g. d1= day 1 of adulthood) and the day when the sample was collected (e.g. d10= day 10 of adulthood). cohort #1: Celegans was treated with water or mianserin (50uM) on day 1 and RNA was harvested on day1 (water only), d3, d5 and day 10 (file titles: h2o d1/d1, h2o d1/d3, h2o d1/d5, h2o d1/d10, mia50 d1/d3, mia50 d1/d5, mia50 d1/d10) cohort #2: Celegans was treated with mianserin (50uM) starting on day 3, and day 5, RNA was harvested on day 5 or 10 (file titles: mia50 d3/d10, mia50 d5/d10, mia50 d3/d5) cohort #3: Celegans was treated with mianserin 2 uM and 10 uM Mianserin on day 1 and Rna harvested on day 5 (file titles: mia2 d1/d5, mia10 d1/d5)
Suppression of transcriptional drift extends C. elegans lifespan by postponing the onset of mortality.
Subject
View SamplesMeig1-deficient mice show male germ cell development defect after they are 28 days old. To understand if the phenotype was caused by altered gene expression due to MEIG1 deficiency, total testicular RNA was isolated from 22 day old and 28 day old wild type and Meig1-deficient mice, microarray was conducted and gene expression was compared between wld-type and Meig1-deficient mice at the two time points.
A MEIG1/PACRG complex in the manchette is essential for building the sperm flagella.
Age, Specimen part
View SamplesIt is fundamentally unknown how normal cellular processes or responses to extracellular stimuli may invoke polyadenylation and degradation of ncRNA substrates or if human disease processes exhibit defects in polyadenylation of ncRNA substrates as part of their pathogenesis. Our results demonstrate that mononuclear cells from subjects with relapsing-remitting multiple sclerosis (RRMS) exhibit pervasive increases in levels of polyadenylated ncRNAs including Y1 RNA, 18S and 28S rRNA, and U1, U2, and U4 snRNAs and these defects are unique to RRMS. Defects in expression of both Ro60 and La proteins in RRMS appear to contribute to increased polyadenylation of ncRNAs. Further, IFN-ß1b, a common RRMS therapy, restores both Ro60 and La levels to normal as well as levels of polyadenylated Y1 RNA and U1 snRNA suggesting that aberrant polyadenylation of ncRNA substrates may have pathogenic consequences. Overall design: We extracted RNA from peripheral whole blood in healthy control subjects and patients with established relapsing-remitting multiple sclerosis using PaxGene tubes.
Defective structural RNA processing in relapsing-remitting multiple sclerosis.
No sample metadata fields
View SamplesTo improve our understanding of lncRNA expression in T cells, we used whole genome sequencing (RNA-seq) to identify lncRNAs expressed in human T cells and those selectively expressed in T cells differentiated under TH1, TH2, or TH17 polarizing conditions. The majority of these lineage-specific lncRNAs are co-expressed with lineage-specific protein-coding genes. These lncRNAs are predominantly intragenic with co-expressed protein-coding genes and are transcribed in sense and antisense orientations with approximately equal frequencies. Further, genes encoding TH lineage specific mRNAs are not randomly distributed across the genome but are highly enriched in the genome in genomic regions also containing genes encoding TH lineage-specific lncRNAs. Our analyses also identify a cluster of antisense lncRNAs transcribed from the RAD50 locus that are selectively expressed under TH2 polarizing conditions and co-expressed with IL4, IL5 and IL13 genes. Depletion of these lncRNAs via selective siRNA treatment demonstrates the critical requirement of these lncRNAs for expression of the TH2 cytokines, IL-4, IL-5 and IL-13. Collectively, our analyses identify new lncRNAs expressed in a TH lineage specific manner and identify a critical role for a cluster of lncRNAs for expression of genes encoding TH2 cytokines. Overall design: Human peripheral blood mononuclear cells (PBMC) were cultured under TH1, TH2, and TH17 polarizing conditions. TH1, TH2, and TH17 primary and effector cultures were isolated and poly(A)+ and total RNA sequencing performed.
Expression and functions of long noncoding RNAs during human T helper cell differentiation.
No sample metadata fields
View SamplesWe used Affymetrix DNA arrays to investigate the extent to which nuclear HDAC4 accumulation affects neuronal gene expression.
HDAC4 governs a transcriptional program essential for synaptic plasticity and memory.
Specimen part
View SamplesThe Carboxy-terminal domain (CTD) of RNA Polymerase II (RNAPII) in mammals undergoes extensive post-translational modification, which is essential for transcriptional initiation and elongation. Here, we show that the CTD of RNAPII is methylated at a single arginine (R1810) by the transcriptional co-activator CARM1. Although methylation at R1810 is present on the hyper-phosphorylated form of RNAPII in vivo, Ser-2 or Ser-5 phosphorylation inhibit CARM1 activity towards this site in vitro, suggesting that methylation occurs before transcription initiation. Mutation of R1810 results in the mis-expression of a variety of snRNAs and snoRNAs, an effect that is also observed in Carm1-/- MEFs. These results demonstrate that CTD methylation facilitates the expression of select RNAs, perhaps serving to discriminate the RNAPII-associated machinery recruited to distinct gene types. Overall design: To address the function of RNAPII methylation, we generated Raji cell lines expressing an RNA Polymerase II resistant to a-amanitin and carrying either wild-type R1810 or an arginine to alanine substitution at that same residue, abolishing R1810 methylation of the CTD. In cells cultured in a-amanitin, the a-amanitin-resistant mutants fully replaced the functions of endogenous RNAPII, allowing us to study if gene-expression is affected by the absence of R1810me
The C-terminal domain of RNA polymerase II is modified by site-specific methylation.
No sample metadata fields
View SamplesThis study sought to evaluate the effects of dietary MeHg exposure on adult female yellow perch (Perca flavescens) and zebrafish (Danio rerio) reproduction by relating controlled exposures with subsequent reproductive effects. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, and the use of zebrafish allowed for a detailed analysis of the molecular effects of MeHg. MeHg exposures at environmentally relevant levels were done in zebrafish for a full life cycle, mimicking a realistic exposure scenario, and in adult yellow perch for twenty weeks, capturing early seasonal ovarian development. In zebrafish, several genes involved in reproductive processes were shown to be dysregulated by RNA-seq and QPCR, but no significant phenotypic or physiological changes were observed with ovarian staging, fecundity, or embryo mortality. Yellow perch did not appear to be affected by MeHg, either at a molecular level, as assessed by QPCR of eight genes in the pituitary, liver, and ovary tissue, or a physiological level, as seen with ovarian somatic index, circulating estradiol, and ovarian staging. Lack of impact in yellow perch limits the usefulness of zebrafish as a model and suggests that the reproductive sensitivity to environmentally relevant levels of MeHg differs between yellow perch and zebrafish. Overall design: 12 samples of total RNA isolated from adult zebrafish ovaries were analyzed. Each exposure group (1, 3, and 10 ppm MeHg) had three replicates, as did the vehicle control. Each sample was comprised of pooled total RNA of up to 6 individual fish.
Female reproductive impacts of dietary methylmercury in yellow perch (Perca flavescens) and zebrafish (Danio rerio).
No sample metadata fields
View SamplesRsf1p is a putative transcription factor required for efficient growth using glycerol as sole carbon source but not for growth on the alternative respiratory carbon source ethanol.
Rsf1p is required for an efficient metabolic shift from fermentative to glycerol-based respiratory growth in S. cerevisiae.
No sample metadata fields
View SamplesGene expression profiling is an important tool in the development of medical countermeasures against chemical warfare agents (CWAs). Non-human primates (NHPs), specifically the rhesus macaque (Macaca mulatta), the cynomologus macaque (Macaca fascicularis) and the African green monkey (Chlorocebus aethiops), are vital models in the development of CWA prophylactics, therapeutics, and diagnostics. However, gene expression profiling of these NHPs is complicated by the fact their genomes are not completely sequenced, and that no commercially available oligonucleotide microarrays (genechips) exist. We, therefore, sought to determine whether gene expression profiling of NHPs could be performed using human genechips. Whole blood RNA was isolated from each species and used to generate genechip probes. Hybridization of the NHP samples to human genechips (Affymetrix Human U133 Plus 2.0) resulted in comparable numbers of transcripts detected compared with human samples. Statistical analysis revealed intraspecies reproducibility of genechip quality control metrics; interspecies comparison between NHPs and humans showed little significant difference in the quality and reproducibility of data generated using human genechips. Expression profiles of each species were compared using principal component analysis (PCA) and hierarchical clustering to determine the similarity of the expression profiles within and across the species. The cynomologus group showed the least intraspecies variability, while the human group showed the greatest intraspecies variability. Intraspecies comparison of the expression profiles identified probesets that were reproducibly detected within each species. Each NHP species was found to be dissimilar to humans; the cynomologus group was the most dissimilar. Interspecies comparison of the expression profiles revealed probesets that were reproducibly detected in all species examined. These results show that human genechips can be used for expression profiling of NHP samples and provide a foundation for the development of tools for comparing human and NHP gene expression profiles.
Comparison of non-human primate and human whole blood tissue gene expression profiles.
No sample metadata fields
View Samples