Levels of C/EBP are low in myeloid blast crisis (BC) of chronic myelogenous leukemia (CML) and its expression in p210BCR/ABL-expressing hematopoietic cells induces granulocytic differentiation, inhibits proliferation and suppresses leukemogenesis. To assess the mechanisms involved in these effects, C/EBP targets were identified by microarray analyses. Upon C/EBP activation, expression of c-Myb and GATA-2 was repressed in 32D-BCR/ABL, K562 and CML-BC primary cells but only c-Myb levels decreased slightly in CD34+ normal progenitors. The role of these two genes for the biological effects of C/EBP was assessed by perturbing their expression in K562 cells. Expression of c-Myb blocked the proliferation inhibition and differentiation-inducing effects of C/EBP while c-Myb siRNA treatment enhanced C/EBP-mediated proliferation inhibition and induced changes in gene expression indicative of monocytic differentiation. GATA-2 expression suppressed the proliferation inhibitory effect of C/EBP but blocked in part the effect on differentiation; GATA-2 siRNA treatment had no effects on C/EBP induction of differentiation but inhibited proliferation of K562 cells, alone or upon C/EBP activation. In summary, the effects of C/EBP in p210BCR/ABL -expressing cells depend, in part, on transcriptional repression of c-Myb and GATA-2. Since perturbation of c-Myb and GATA-2 expression has non identical consequences for proliferation and differentiation of K562 cells, the effects of C/EBP appear to involve different transcription-regulated targets.
Transcriptional repression of c-Myb and GATA-2 is involved in the biologic effects of C/EBPalpha in p210BCR/ABL-expressing cells.
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View SamplesWe were interested to explain why p53 binds some high affinity sites in contrast to other high affinity sites that are not bound by p53.
p53 binds preferentially to genomic regions with high DNA-encoded nucleosome occupancy.
Cell line, Treatment
View SamplesNormal cells require continuous exposure to growth factors, in order to cross a restriction point and commit to cell cycle progression. This can be replaced by two short, appropriately spaced pulses of growth factors, where the first pulse primes a process, which is completed by the second pulse, and enables restriction point crossing. Through integration of comprehensive proteomic and transcriptomic analyses of each pulse, we identified three processes that regulate restriction point crossing: (i) The first pulse induces essential metabolic enzymes and activates p53-dependent restraining processes. (ii) The second pulse eliminates, via the PI3K/AKT pathway, the suppressive action of p53, as well as (iii) sets an ERK-EGR1 threshold mechanism, which digitizes graded external signals into an all-or-none decision obligatory for S-phase entry. Together, our findings uncover novel gating mechanisms, which ensure that cells ignore fortuitous growth factors, and undergo proliferation only in response to consistent mitogenic signals.
Two phases of mitogenic signaling unveil roles for p53 and EGR1 in elimination of inconsistent growth signals.
Specimen part, Cell line
View SamplesExpression data from NIH-3T3 cells left uninfected or infected with MCMV for 2, 4 or 6h on total RNA as well as newly transcribed RNA labeled for 1-2, 3-4, and 5-6hpi. For newly transcribed RNA, the isolated RNA was labeled for 1h and separated from total cellular RNA following Trizol RNA preparation and thiol-specific biotinylation. We used microarrays to analyze the effects of MCMV infection in total and newly transcribed RNA.
Real-time transcriptional profiling of cellular and viral gene expression during lytic cytomegalovirus infection.
Disease, Cell line, Time
View SamplesA sheet of choroid plexus epithelial cells extends into each cerebral ventricle and secretes signaling factors into the cerebrospinal fluid (CSF). To evaluate whether differences in the CSF proteome across ventricles arise, in part, from regional differences in choroid plexus gene expression, we defined the transcriptome of lateral ventricle (telencephalic) vs. fourth ventricle (hindbrain) choroid plexus. We find that positional identities of mouse, macaque, and human choroid plexi derive from gene expression domains that parallel their axial tissues of origin. We then show that molecular heterogeneity between telencephalic and hindbrain choroid plexi contributes to region-specific, age-dependent protein secretion in vitro. Transcriptome analysis of FACS-purified choroid plexus epithelial cells also predicts their cell type-specific secretome. Spatial domains with distinct protein expression profiles were observed within each choroid plexus. We propose that regional differences between choroid plexi contribute to dynamic signaling gradients across the mammalian cerebroventricular system. Overall design: Two-factor design with two levels per factor and n=2 biological replicates. Lateral (telencephalic) and fourth (hindbrain) choroid plexus samples are paired in that they are isolated from the same brains.
Spatially heterogeneous choroid plexus transcriptomes encode positional identity and contribute to regional CSF production.
No sample metadata fields
View SamplesCells producing adrenalin are largely derived from nerve-associated Schwann cell precursors via an intermediate progenitor “bridge” cell. We demonstrate that large numbers of chromaffin cells arise from peripheral glial stem cells, termed Schwann cell precursors (SCPs) Overall design: SCPs migrate along the visceral motor nerve to the vicinity of the forming adrenal gland where they detach from the nerve and form post-synaptic neuroendocrine chromaffin cells. An intricate molecular logic drives two sequential phases of gene expression, one unique for a distinct transient cellular state and another for cell-type specification. Subsequently, these programs downregulate SCP- and upregulate chromaffin-cell-gene networks. The adrenal medulla forms through limited cell expansion and requires the recruitment of numerous SCPs. Thus, peripheral nerves serve as a stem cell niche for neuroendocrine system development.
RNA velocity of single cells.
Specimen part, Subject
View SamplesHek293 cells were metabolically labelled using 4-thiouracil as described in (Schwalb et al, Science. 2016 Jun 3;352(6290):1225-8) but without fragmentation, and then bulk RNA was prepared for sequencing using the STRT method (Islam et al, Genome Res. 2011 Jul;21(7):1160-7). Samples were incubated in duplicate for 5, 15 and 30 minutes and included an unlabeled control representing the steady-state expression state. Overall design: 2 samples each of 4 incubation times, 2 cDNA preparations, 2 tagmentation replicates, and 2 biological replicates
RNA velocity of single cells.
Cell line, Subject
View SamplesExtracellular vesicles (EVs) enable cell-to-cell communication in the nervous system essential for development and adult function. Endosomal Sorting Complex Required for Transport (ESCRT) complex proteins regulate EV formation and release. Recent work shows loss of function (LOF) mutations in, CHMP1A, which encodes one ESCRT-III member, cause autosomal recessive microcephaly with pontocerebellar hypoplasia in humans (Mochida et al., 2012). Here we show CHMP1A is required for maintenance of progenitors in human cerebral organoids and that mouse Chmp1a is required for progenitor proliferation in cortex and cerebellum and specifically for sonic hedgehog (SHH) mediated proliferation through SHH secretion. CHMP1A mutation reduces intraluminal vesicle (ILV) formation in multivesicular bodies (MVBs), and EV release. SHH protein is present on a subset of EVs marked by a unique set of proteins we call ART-EVs. CHMP1A's requirement in formation of ART-EVs and other EVs provides a model to elucidate EV functions in multiple brain processes. Overall design: Gene expression profiling in a hiPSC WT line and a hiPSC CHMP1A null line. Comparative analysis by RNA-seq in hIPSCs and directed differentiation to cerebral organoids. Treatment with smoothened agonist (SAG) was used for examination of SHH dependent response in WT and CHMP1A null organoids.
The ESCRT-III Protein CHMP1A Mediates Secretion of Sonic Hedgehog on a Distinctive Subtype of Extracellular Vesicles.
Specimen part, Subject
View SamplesCholecystokinin (CCK) is a satiety hormone produced by discrete enteroendocrine cells scattered among absorptive cells of the small intestine. CCK is released into blood following a meal; however, the mechanisms inducing hormone secretion are largely unknown. Ingested fat is the major stimulant of CCK secretion. We recently identified a novel member of the lipoprotein remnant receptor family known as immunoglobulin-like domain containing receptor 1 (ILDR1) in intestinal CCK cells and postulated that this receptor conveyed the signal for fat-stimulated CCK secretion. In the intestine, ILDR1 is expressed exclusively in CCK cells. Orogastric administration of fatty acids elevated blood levels of CCK in wild type but not ILDR1-deficient mice, although the CCK secretory response to trypsin inhibitor was retained. The uptake of fluorescently labeled lipoproteins in ILDR1-transfected CHO cells and release of CCK from isolated intestinal cells required a unique combination of fatty acid plus HDL. CCK secretion secondary to ILDR1 activation is associated with increased [Ca2+]i consistent with regulated hormone release. These findings demonstrate that ILDR1 regulates CCK release through a mechanism dependent on fatty acids and lipoproteins and that absorbed fatty acids regulate gastrointestinal hormone secretion.
Immunoglobulin-like domain containing receptor 1 mediates fat-stimulated cholecystokinin secretion.
Specimen part
View SamplesChoroid plexuses (CP) develop early during development. They form a barrier between the blood and the cerebrospinal fluid, and fulfill important protective and nutritive functions. We used Affymetrix microarrays to assess whether CP of the lateral ventricles (LVCP) have similar functions in developing and adult brain. We identified distinct families of protective and transport genes and found that most of these genes were already well expressed during development.
Developmental changes in the transcriptome of the rat choroid plexus in relation to neuroprotection.
Specimen part
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