2,935 research outputs found
Impact of Building Information Modeling Implementation on the Acceptance of Integrated Delivery Systems: Structural Equation Modeling Analysis
In recent years, building information modeling (BIM) has been increasingly employed by the architecture, engineering and construction industry worldwide as a result of digital government initiatives. In spite of some promising early evidence on the benefits of BIM, the momentum of this top-down drive should build upon after-implementation empirical evidence. Through the structural equation modeling analysis of survey returns from 145 Chinese BIM-enabled projects, this research demonstrates that BIMās degree of implementation can positively affect the acceptability of integrated project delivery (IPD) in the future via increased perception of the need for supply chain incentivization and improved communication quality enabled by BIM. Rolling out BIM on a wider scale may yield an additional benefit in lowering the barrier to the implementation of IPD systems. This finding can serve as evidential support for government mandates that require the compulsory adoption of BIM in public projects
Noncoding RNA Landmarks of Pluripotency and Reprogramming
Noncoding RNAs have emerged as important determinants of pluripotency and reprogramming. In this issue of Cell Stem Cell, Kosik and colleagues now provide a detailed map of microRNA expression patterns to infer the biological states of embryonic and induced pluripotent stem cells
Molecular studies of Fas signaling and programmed cell death
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 1998.Includes bibliographical references.by Howard Y. Chang.Ph.D
Daxx, a Novel Fas-Binding Protein That Activates JNK and Apoptosis
The Fas cell surface receptor induces apoptosis upon receptor oligomerization. We have identified a novel signaling protein, termed Daxx, that binds specifically to the Fas death domain. Overexpression of Daxx enhances Fas-mediated apoptosis and activates the Jun N-terminal kinase (JNK) pathway. A C-terminal portion of Daxx interacts with the Fas death domain, while a different region activates both JNK and apoptosis. The Fas-binding domain of Daxx is a dominant-negative inhibitor of both Fas-induced apoptosis and JNK activation, while the FADD death domain partially inhibits death but not JNK activation. The Daxx apoptotic pathway is sensitive to both Bcl-2 and dominant-negative JNK pathway components and acts cooperatively with the FADD pathway. Thus, Daxx and FADD define two distinct apoptotic pathways downstream of Fas
Single-cell epigenomic variability reveals functional cancer heterogeneity.
BackgroundCell-to-cell heterogeneity is a major driver of cancer evolution, progression, and emergence of drug resistance. Epigenomic variation at the single-cell level can rapidly create cancer heterogeneity but is difficult to detect and assess functionally.ResultsWe develop a strategy to bridge the gap between measurement and function in single-cell epigenomics. Using single-cell chromatin accessibility and RNA-seq data in K562 leukemic cells, we identify the cell surface marker CD24 as co-varying with chromatin accessibility changes linked to GATA transcription factors in single cells. Fluorescence-activated cell sorting of CD24 high versus low cells prospectively isolated GATA1 and GATA2 high versus low cells. GATA high versus low cells express differential gene regulatory networks, differential sensitivity to the drug imatinib mesylate, and differential self-renewal capacity. Lineage tracing experiments show that GATA/CD24hi cells have the capability to rapidly reconstitute the heterogeneity within the entire starting population, suggesting that GATA expression levels drive a phenotypically relevant source of epigenomic plasticity.ConclusionSingle-cell chromatin accessibility can guide prospective characterization of cancer heterogeneity. Epigenomic subpopulations in cancer impact drug sensitivity and the clonal dynamics of cancer evolution
A Transcriptional Program Mediating Entry into Cellular Quiescence
The balance of quiescence and cell division is critical for tissue homeostasis and organismal health. Serum stimulation of fibroblasts is well studied as a classic model of entry into the cell division cycle, but the induction of cellular quiescence, such as by serum deprivation (SD), is much less understood. Here we show that SS and SD activate distinct early transcriptional responses genome-wide that converge on a late symmetric transcriptional program. Several serum deprivation early response genes (SDERGs), including the putative tumor suppressor genes SALL2 and MXI1, are required for cessation of DNA synthesis in response to SD and induction of additional SD genes. SDERGs are coordinately repressed in many types of human cancers compared to their normal counterparts, and repression of SDERGs predicts increased risk of cancer progression and death in human breast cancers. These results identify a gene expression program uniquely responsive to loss of growth factor signaling; members of SDERGs may constitute novel growth inhibitors that prevent cancer
Joint single-cell DNA accessibility and protein epitope profiling reveals environmental regulation of epigenomic heterogeneity.
Here we introduce Protein-indexed Assay of Transposase Accessible Chromatin with sequencing (Pi-ATAC) that combines single-cell chromatin and proteomic profiling. In conjunction with DNA transposition, the levels of multiple cell surface or intracellular protein epitopes are recorded by index flow cytometry and positions in arrayed microwells, and then subject to molecular barcoding for subsequent pooled analysis. Pi-ATAC simultaneously identifies the epigenomic and proteomic heterogeneity in individual cells. Pi-ATAC reveals a casual link between transcription factor abundance and DNA motif access, and deconvolute cell types and states in the tumor microenvironment in vivo. We identify a dominant role for hypoxia, marked by HIF1Ī± protein, in the tumor microvenvironment for shaping the regulome in a subset of epithelial tumor cells
Module Map of Stem Cell Genes Guides Creation of Epithelial Cancer Stem Cells
SummarySelf-renewal is a hallmark of stem cells and cancer, but existence of a shared stemness program remains controversial. Here, we construct a gene module map to systematically relate transcriptional programs in embryonic stem cells (ESCs), adult tissue stem cells, and human cancers. This map reveals two predominant gene modules that distinguish ESCs and adult tissue stem cells. The ESC-like transcriptional program is activated in diverse human epithelial cancers and strongly predicts metastasis and death. c-Myc, but not other oncogenes, is sufficient to reactivate the ESC-like program in normal and cancer cells. In primary human keratinocytes transformed by Ras and IĪŗBĪ±, c-Myc increases the fraction of tumor-initiating cells by 150-fold, enabling tumor formation and serial propagation with as few as 500 cells. c-Myc-enhanced tumor initiation is cell-autonomous and independent of genomic instability. Thus, activation of an ESC-like transcriptional program in differentiated adult cells may induce pathologic self-renewal characteristic of cancer stem cells
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Identification of proteins binding coding and non-coding human RNAs using protein microarrays
Background: The regulation and function of mammalian RNAs has been increasingly appreciated to operate via RNA-protein interactions. With the recent discovery of thousands of novel human RNA molecules by high-throughput RNA sequencing, efficient methods to uncover RNA-protein interactions are urgently required. Existing methods to study proteins associated with a given RNA are laborious and require substantial amounts of cell-derived starting material. To overcome these limitations, we have developed a rapid and large-scale approach to characterize binding of in vitro transcribed labeled RNA to ~9,400 human recombinant proteins spotted on protein microarrays. Results: We have optimized methodology to probe human protein microarrays with full-length RNA molecules and have identified 137 RNA-protein interactions specific for 10 coding and non-coding RNAs. Those proteins showed strong enrichment for common human RNA binding domains such as RRM, RBD, as well as K homology and CCCH type zinc finger motifs. Previously unknown RNA-protein interactions were discovered using this technique, and these interactions were biochemically verified between TP53 mRNA and Staufen1 protein as well as between HRAS mRNA and CNBP protein. Functional characterization of the interaction between Staufen 1 protein and TP53 mRNA revealed a novel role for Staufen 1 in preserving TP53 RNA stability. Conclusions: Our approach demonstrates a scalable methodology, allowing rapid and efficient identification of novel human RNA-protein interactions using RNA hybridization to human protein microarrays. Biochemical validation of newly identified interactions between TP53-Stau1 and HRAS-CNBP using reciprocal pull-down experiments, both in vitro and in vivo, demonstrates the utility of this approach to study uncharacterized RNA-protein interactions.Stem Cell and Regenerative Biolog
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