77 research outputs found
Development of a methods repository for food choice behaviors and drivers at the household and individual levels
This brief identifies important constructs for assessing drivers of food choice behaviors and describes progress on the development of a repository of instruments and measures for assessing these constructs.
OBJECTIVES
1. List constructs that can be assessed to understand drivers of household and individual food choice behaviors.
2. Identify instruments and measures to assess each food choice construct and organize these into a searchable repository.
3. Illustrate the use of the Food Choice Repository
A New Isoform of the Histone Demethylase JMJD2A/KDM4A Is Required for Skeletal Muscle Differentiation
In proliferating myoblasts, muscle specific genes are silenced by epigenetic modifications at their promoters, including histone H3K9 methylation. Derepression of the promoter of the gene encoding the myogenic factor myogenin (Myog) is key for initiation of muscle differentiation. The mechanism of H3K9 demethylation at the Myog promoter is unclear, however. Here, we identify an isoform of the histone demethylase JMJD2A/KDM4A that lacks the N-terminal demethylase domain (ΔN-JMJD2A). The amount of ΔN-JMJD2A increases during differentiation of C2C12 myoblasts into myotubes. Genome-wide expression profiling and exon-specific siRNA knockdown indicate that, in contrast to the full-length protein, ΔN-JMJD2A is necessary for myotube formation and muscle-specific gene expression. Moreover, ΔN-JMJD2A promotes MyoD-induced conversion of NIH3T3 cells into muscle cells. ChIP-on-chip analysis indicates that ΔN-JMJD2A binds to genes mainly involved in transcriptional control and that this binding is linked to gene activation. ΔN-JMJD2A is recruited to the Myog promoter at the onset of differentiation. This binding is essential to promote the demethylation of H3K9me2 and H3K9me3. We conclude that induction of the ΔN-JMJD2A isoform is crucial for muscle differentiation: by directing the removal of repressive chromatin marks at the Myog promoter, it promotes transcriptional activation of the Myog gene and thus contributes to initiation of muscle-specific gene expression
NF-Y Recruits Ash2L to Impart H3K4 Trimethylation on CCAAT Promoters
BACKGROUND: Different histone post-translational modifications (PTMs) are crucial in the regulation of chromatin, including methylations of H3 at Lysine 4 by the MLL complex. A relevant issue is how this is causally correlated to the binding of specific transcription factors (TFs) in regulatory regions. NF-Y is a TF that regulates 30% of mammalian promoters containing the widespread CCAAT element. We and others established that the presence of H3K4me3 is dependent upon the binding of NF-Y. Here, we investigate the mechanisms of H3K4me3 deposition by NF-Y. METHODS: We employed Chromatin Immunoprecipitation in cells in which Ash2L and NF-Y subunits were knocked down by RNAi, to monitor the presence of histones PTMs and components of the MLL complex. We performed gene expression profiling of Ash2L-knocked down cells and analyzed the regulated genes. We performed ChIPs in leukemic cells in which MLL1 is devoid of the methyltransferase domain and fused to the AF4 gene. RESULTS: Knock down of the Ash2L subunit of MLL leads to a decrease in global H3K4me3 with a concomitant increase in H3K79me2. Knock down of NF-Y subunits prevents promoter association of Ash2L, but not MLL1, nor WDR5, and H3K4me3 drops dramatically. Endogenous NF-Y and Ash2L specifically interact in vivo. Analysis of the promoters of Ash2L regulated genes, identified by transcriptional profiling, suggests that a handful TF binding sites are moderately enriched, among which the CCAAT box. Finally, leukemic cells carrying the MLL-AF4 translocation show a decrease of H3K4me3, absence of Ash2L and increase in H3K79me2, while NF-Y binding was not significantly affected. CONCLUSIONS: Three types of conclusions are reached: (i) H3K4 methylation is not absolutely required for NF-Y promoter association. (ii) NF-Y acts upstream of H3K4me3 deposition by recruiting Ash2L. (iii) There is a general cross-talk between H3K4me3 and H3K79me2 which is independent from the presence of MLL oncogenic fusions
Recommended from our members
A rapid evidence assessment of UK citizen and industry understandings of sustainability - Why our understanding of sustainable food is important when making food choices
The Food Standards Agency (FSA) commissioned the Centre for Food Policy at City, University of London and collaborative partners to carry out a Rapid Evidence Assessment (REA) on UK citizen perceptions of food sustainability. This Executive Summary presents the findings of this REA, along with academic definitions of food sustainability (and how citizen definitions compare to these), and a rapid review of industry and NGO approaches to sustainability amongst a small random selection of 21 organisations across the food system. Please refer to the full report and appendices for detailed findings and methodology.
The main research question addressed is: What does sustainability mean to UK citizens when it comes to food and diet? The report addresses the following secondary questions: How does the UK academic literature define sustainability, ‘sustainable food’ and ‘sustainable diet’?, how do citizens’ perceptions compare to this, and ‘What does sustainability mean to industry when it comes to food and diet?’. 'A number of sub-questions and themes were explored to answer the main research question, such as understanding and importance of sustainability and its impact on food choices, trade-offs, drivers and barriers to sustainable food choices and differences across demographic groups.
To note: In this Executive Summary we refer to communities and individuals in the UK as “UK citizens”, rather than UK consumers. The use of the term citizen is not meant to be a reference to citizenship either directly via birth in the UK or through the process of naturalization
Global Regulator SATB1 Recruits β-Catenin and Regulates TH2 Differentiation in Wnt-Dependent Manner
Chromatin organizer SATB1 and Wnt transducer β-catenin form a complex and regulate expression of GATA3 and TH2 cytokines in Wnt-dependent manner and orchestrate TH2 lineage commitment
TRAF6 Promotes Myogenic Differentiation via the TAK1/p38 Mitogen-Activated Protein Kinase and Akt Pathways
p38 mitogen-activated protein kinase (MAPK) is an essential kinase involved in myogenic differentiation. Although many substrates of p38 MAPK have been identified, little is known about its upstream activators during myogenic differentiation. TRAF6 is known to function in cytokine signaling during inflammatory responses. However, not much is known about its role in myogenic differentiation and muscle regeneration. We showed here that TRAF6 and its intrinsic ubiquitin E3 ligase activity are required for myogenic differentiation. In mouse myoblasts, knockdown of TRAF6 compromised the p38 MAPK and Akt pathways, while deliberate activation of either pathway rescued the differentiation defect caused by TRAF6 knockdown. TAK1 acted as a key signal transducer downstream of TRAF6 in myogenic differentiation. In vivo, knockdown of TRAF6 in mouse muscles compromised the injury-induced muscle regeneration without impairing macrophage infiltration and myoblast proliferation. Collectively, we demonstrated that TRAF6 promotes myogenic differentiation and muscle regeneration via the TAK1/p38 MAPK and Akt pathways
SMAR1 binds to T(C/G) repeatvand inhibits tumor progression by regulating miR-371-373 cluster
Chromatin architecture and dynamics are regulated by various histone and non-histone proteins. The
matrix attachment region binding proteins (MARBPs) play a central role in chromatin organization and function through numerous regulatory proteins. In the present study, we demonstrate that nuclear matrix protein SMAR1 orchestrates global gene regulation as determined by massively parallel ChIPsequencing. The study revealed that SMAR1 binds to T(C/G) repeat and targets genes involved in diverse
biological pathways. We observe that SMAR1 binds and targets distinctly different genes based on the
availability of p53. Our data suggest that SMAR1 binds and regulates one of the imperative microRNA clusters in cancer and metastasis, miR-371-373. It negatively regulates miR-371-373 transcription as confirmed by SMAR1 overexpression and knockdown studies. Further, deletion studies indicate that a ~200 bp region in the miR-371-373 promoter is necessary for SMAR1 binding and transcriptional
repression. Recruitment of HDAC1/mSin3A complex by SMAR1, concomitant with alteration of histone marks results in downregulation of the miRNA cluster. The regulation of miR-371-373 by SMAR1 inhibits breast cancer tumorigenesis and metastasis as determined by in vivo experiments. Overall, our study highlights the binding of SMAR1 to T(C/G) repeat and its role in cancer through miR-371-37
p53 Target Gene SMAR1 Is Dysregulated in Breast Cancer: Its Role in Cancer Cell Migration and Invasion
Tumor suppressor SMAR1 interacts and stabilizes p53 through phosphorylation at its serine-15 residue. We show that SMAR1 transcription is regulated by p53 through its response element present in the SMAR1 promoter. Upon Doxorubicin induced DNA damage, acetylated p53 is recruited on SMAR1 promoter that allows activation of its transcription. Once SMAR1 is induced, cell cycle arrest is observed that is correlated to increased phospho-ser-15-p53 and decreased p53 acetylation. Further we demonstrate that SMAR1 expression is drastically reduced during advancement of human breast cancer. This was correlated with defective p53 expression in breast cancer where acetylated p53 is sequestered into the heterochromatin region and become inaccessible to activate SMAR1 promoter. In a recent report we have shown that SMAR1 represses Cyclin D1 transcription through recruitment of HDAC1 dependent repressor complex at the MAR site of Cyclin D1 promoter. Here we show that downmodulation of SMAR1 in high grade breast carcinoma is correlated with upregulated Cyclin D1 expression. We also established that SMAR1 inhibits tumor cell migration and metastases through inhibition of TGFβ signaling and its downstream target genes including cutl1 and various focal adhesion molecules. Thus, we report that SMAR1 plays a central role in coordinating p53 and TGFβ pathways in human breast cancer
An epigenetic mechanism mediates developmental nicotine effects on neuronal structure and behavior
Developmental nicotine exposure causes persistent changes in cortical neuron morphology and in behavior. We used microarray screening to identify master transcriptional or epigenetic regulators mediating these effects of nicotine and discovered increases in Ash2lmRNA, encoding a component of a histone methyltransferase complex. We therefore examined genome-wide changes in trimethylation of histone H3 on Lys4 (H3K4me3), a mark induced by the Ash2l complex associated with increased gene transcription. A large proportion of regulated promoter sites were involved in synapse maintenance. We found that Mef2c interacts with Ash2l and mediates changes in H3K4me3. Knockdown of Ash2l or Mef2c abolished nicotine-mediated alterations of dendritic complexity in vitro and in vivo, and attenuated nicotine-dependent changes in passive avoidance behavior. In contrast, overexpression mimicked nicotine-mediated alterations of neuronal structure and passive avoidance behavior. These studies identify Ash2l as a target induced by nicotinic stimulation that couples developmental nicotine exposure to changes in brain epigenetic marks, neuronal structure and behavior
TESS Hunt for Young and Maturing Exoplanets (THYME) VII : Membership, rotation, and lithium in the young cluster Group-X and a new young exoplanet
The public, all-sky surveys Gaia and TESS provide the ability to identify new
young associations and determine their ages. These associations enable study of
planetary evolution by providing new opportunities to discover young
exoplanets. A young association was recently identified by Tang et al. and
F{\"u}rnkranz et al. using astrometry from Gaia (called "Group-X" by the
former). In this work, we investigate the age and membership of this
association; and we validate the exoplanet TOI 2048 b, which was identified to
transit a young, late G dwarf in Group-X using photometry from TESS. We first
identified new candidate members of Group-X using Gaia EDR3 data. To infer the
age of the association, we measured rotation periods for candidate members
using TESS data. The clear color--period sequence indicates that the
association is the same age as the Myr-old NGC 3532. We obtained
optical spectra for candidate members that show lithium absorption consistent
with this young age. Further, we serendipitously identify a new, small
association nearby Group-X, which we call MELANGE-2. Lastly, we statistically
validate TOI 2048 b, which is \rearth\ radius planet on a 13.8-day
orbit around its 300 Myr-old host star.Comment: Revised to correct error in reported planet radius (original: 2.1
Earth radii, corrected: 2.6 Earth radii) and units for planetary radius ratio
entries in Table 8. All data tables available open-access with the AJ articl
- …