Normal 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 SamplesGrowth factors (GFs) suppression by steroid hormones recurs in embryology and is co-opted in pathology. While studying mammary cell migration, which is stimulated by GFs and antagonized by glucocorticoids (GCs), we found that GCs inhibit positive feedback loops activated by GFs and stimulate the reciprocal negative loops. Although no alterations in DNA methylation accompany the transcriptional events instigated by either stimulus, forced demethylation of distal regions broadened the repertoire of inducible genes. Our data indicate that the crosstalk involve transcription factors like p53 and NF-kB, along with reduced pausing (and traveling) of RNA polymerase II (RNAPII) at the promoters (and bodies) of GF-inducible genes. In addition, while GFs hyper-acetylated chromatin at unmethylated promoters and enhancers of genes involved in motility, GCs hypo-acetylated the corresponding regions. In conclusion, stably unmethylated genomic regions that encode feedback regulatory modules and differentially recruit RNAPII and acetylases/deacetylases underlie suppression of growth factor signaling by glucocorticoids. Overall design: RNA-Seq – EGF treatemnt for 60 min of WT and DNMT1a and DNMT3b double-knockout HCT116 cells
Epigenetic mechanisms underlie the crosstalk between growth factors and a steroid hormone.
Treatment, Subject
View SamplesTo identify molecular pathological alterations in AD brains, we performed interspecies comparative microarray analyses using RNAs prepared from postmortem human brain tissues donated for the Hisayama study and hippocampal RNAs from the triple-transgenic mouse model of AD (3xTg-AD)
Altered expression of diabetes-related genes in Alzheimer's disease brains: the Hisayama study.
Sex, Age, Specimen part
View SamplesTo identify molecular pathological alterations in AD brains, we performed interspecies comparative microarray analyses using RNAs prepared from postmortem human brain tissues donated for the Hisayama study and hippocampal RNAs from the triple-transgenic mouse model of AD (3xTg-AD)
Altered expression of diabetes-related genes in Alzheimer's disease brains: the Hisayama study.
Sex, Age, Specimen part
View SamplesGeneChip-based screen for genes induced in the initial phase of neural differentiation from ES cells.
Intrinsic transition of embryonic stem-cell differentiation into neural progenitors.
No sample metadata fields
View SamplesRegulation of organ size is important for development and tissue homeostasis. In Drosophila, Hippo signaling controls organ size by regulating the activity of a TEAD transcription factor, Scalloped, through modulation of its coactivator protein Yki. The role of mammalian Tead proteins in growth regulation, however, remains unknown. Here we examined the role of mouse Tead proteins in growth regulation. In NIH3T3 cells, cell density and Hippo signaling regulated the activity of Tead proteins by modulating nuclear localization of a Yki homologue, Yap, and the resulting change in Tead activity altered cell proliferation. Tead2-VP16 mimicked Yap overexpression, including increased cell proliferation, reduced cell death, promotion of EMT, lack of cell contact inhibition, and promotion of tumor formation. Growth promoting activities of various Yap mutants correlated with their Tead-coactivator activities. Tead2-VP16 and Yap regulated largely overlapping sets of genes. However, only a few of the Tead/Yapregulated genes in NIH3T3 cells were affected in Tead1-/-;Tead2-/- or Yap-/- embryos. Most of the previously identified Yap-regulated genes were not affected in NIH3T3 cells or mutant mice. In embryos, levels of nuclear Yap and Tead1 varied depending on cell types. Strong nuclear accumulation of Yap and Tead1 were seen in myocardium, correlating with requirements of Tead1 for proliferation. However, their distribution did not always correlate with proliferation. Taken together, mammalian Tead proteins regulate cell proliferation and contact inhibition as a transcriptional mediator of Hippo signaling, but the mechanisms by which Tead/Yap regulate cell proliferation differ depending on cell types, and Tead, Yap and Hippo signaling may play multiple roles in mouse embryos.
Mammalian Tead proteins regulate cell proliferation and contact inhibition as transcriptional mediators of Hippo signaling.
No sample metadata fields
View SamplesWe found that a H3K4 specific histone methyltransferase MLL1, a mammalian homologue of Drosophila trithorax, is essential for circadian transcription. MLL1 is in a complex with CLOCK:BMAL1 and contributes to their rhythmic recruitment to circadian promoters and cyclic H3K4 tri-metylation. To analyze the function of MLL1 on circadian gene regulation, we performed comparative microarray analysis of global gene expression levels in WT and MLL1-deficient MEF, at two different circadian time points (CT18 and CT30). This analysis identified several genes whose expression levels were remarkably changed between CT18 and CT30 in WT and MLL1-KO MEF. Typical clock-regulated genes such as Per2, Per3, Bmal1, or Dbp were found to be changing in WT but not in MLL1-KO MEFs.
The histone methyltransferase MLL1 permits the oscillation of circadian gene expression.
Specimen part, Time
View SamplesHuman embryonic stem cells (hESCs) have the unique property of immortality, ability to infinitely self-renew and survive in vitro. In contrast to tumor-deribed cells, their immortality are free from any genomic abberations. Instead, they depend on the AKAP-Lbc/Rho signaling cascade. To understand the downstream way, we performed RNA-seq analyses between normal and AKAP-Lbc-depleted hESCs using the doxycyclin-inducible gene silensing strategy. Overall design: We use the genetically modified hESCs in which AKAP-13-targeting shRNA is induced by doxycyclin(dox) treatment. To minimize cell loss during treatment, anti-apoptotic factor Bcl-XL is overexpressed. We collected RNA from dox-treated and untreated cells in biological triplicate. We measured gene expression in these 2 sample groups using RNA-seq (illumina HiSeq) .
Rho-Signaling-Directed YAP/TAZ Activity Underlies the Long-Term Survival and Expansion of Human Embryonic Stem Cells.
No sample metadata fields
View SamplesGenome instability is a potential limitation to the research and therapeutic application of induced pluripotent stem cells (iPSCs). Observed genomic variations reflect the combined activities of DNA damage, cellular DNA damage response (DDR), and selection pressure in culture. To understand the contribution of DDR on the distribution of copy number variations (CNVs) in iPSCs, we mapped CNVs of iPSCs with mutations in the central DDR gene ATM onto genome organization landscapes defined by genome-wide replication timing profiles. We show that following reprogramming the early and late replicating genome is differentially affected by CNVs in ATM deficient iPSCs relative to wild type iPSCs. Specifically, the early replicating regions had increased CNV losses during retroviral reprogramming. This differential CNV distribution was not present after later passage or after episomal reprogramming. Comparison of different reprogramming methods in the setting of defective DNA damage response reveals unique vulnerability of early replicating open chromatin to retroviral vectors.
Influence of ATM-Mediated DNA Damage Response on Genomic Variation in Human Induced Pluripotent Stem Cells.
Specimen part
View SamplesCancer cells have wide variety of gene expression profile. The objective of the study is to reveal the cancer-associated gene expression profile.
Gene expression signatures for identifying diffuse-type gastric cancer associated with epithelial-mesenchymal transition.
Specimen part
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