scholarly journals Endogenous BioID elucidates TCF7L1 interactome modulation upon GSK-3 inhibition in mouse ESCs

2018 ◽  
Author(s):  
Steven Moreira ◽  
Caleb Seo ◽  
Victor Gordon ◽  
Sansi Xing ◽  
Ruilin Wu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Transcription Factors ◽  
Target Gene ◽  
Single Copy ◽  
List Type ◽  
Interacting Proteins ◽  
Mouse Escs ◽  
Biotin Ligase ◽  
Biotin Labeling

Modulation of Wnt target gene expression via the TCF/LEFs remains poorly understood. We employ proximity-based biotin labeling (BioID) to examine GSK-3 inhibitor effects on the TCF7L1 interactome in mouse ESCs. We generated ESC lines with biotin ligase BirA* fused to TCF7L1 by knocking it into the endogenous TCF7L1 locus or by inserting a doxinducible BirA*-TCF7L1 transgene into the Rosa26 locus. Induction yielded BirA*-TCF7L1 levels 3-fold higher than in the endogenous system, but substantial overlap in biotinylated proteins with high peptide counts were detected by each method. Known TCF7L1 interactors TLE3/4 and β-catenin, and numerous proteins not previously associated with TCF7L1, were identified in both systems. Despite reduced BirA*-TCF7L1 levels, the number of hits identified with both BioID approaches increased after GSK-3 inhibition. We elucidate the network of TCF7L1 proximal proteins regulated by GSK-3 inhibition, validate the utility of endogenous BioID, and provide mechanistic insights into TCF7L1 target gene regulation.HighlightsBirA*-TCF7L1 at single-copy physiological levels generates robust BioID dataCHIR99021 reduces TCF7L1 levels but increases detectable TCF7L1-proximal proteinsThe TCF7L1 interactome of largely epigenetic/transcription factors fluctuates with GSK-3 inhibitionJMJD1C, SALL4 and BRG1/SMARCA4 are validated as TCF7L-interacting proteins

Gene regulation through chromatin remodelling by members of the nuclear receptor superfamily

2000 ◽  
Vol 28 (4) ◽  
pp. 369-373 ◽  
Author(s):  
I. J. McEwan
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Transcription Factors ◽  
Thyroid Hormones ◽  
Target Gene ◽  
Protein Complexes ◽  
Nuclear Receptor Superfamily ◽  
Target Gene Expression ◽  
Dna Elements ◽  
Introductory Review

The intracellular receptors for steroid hormones, thyroid hormones, retinoids and vitamin D3 are known to bind to specific DNA elements and thus regulate target gene expression. This introductory review and the following papers address some of the mechanisms underlying this action. In particular, the ability of this family of transcription factors to recruit multi-protein complexes that have the capacity to remodel chromatin structure in order to silence or activate target gene expression is discussed.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals Epigenetic manipulation of gene expression

2005 ◽  
Vol 169 (6) ◽  
pp. 847-857 ◽  
Author(s):  
Rudy L. Juliano ◽  
Vidula R. Dixit ◽  
Hyunmin Kang ◽  
Tai Young Kim ◽  
Yuko Miyamoto ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Gene Regulation ◽  
Transcription Factors ◽  
Rna Interference ◽  
Antisense Oligonucleotide ◽  
Significant Progress ◽  
Direct Experience ◽  
Key Features ◽  
Epigenetic Manipulation

Cell biologists have been afforded extraordinary new opportunities for experimentation by the emergence of powerful technologies that allow the selective manipulation of gene expression. Currently, RNA interference is very much in the limelight; however, significant progress has also been made with two other approaches. Thus, antisense oligonucleotide technology is undergoing a resurgence as a result of improvements in the chemistry of these molecules, whereas designed transcription factors offer a powerful and increasingly convenient strategy for either up- or down-regulation of targeted genes. This mini-review will highlight some of the key features of these three approaches to gene regulation, as well as provide pragmatic guidance concerning their use in cell biological experimentation based on our direct experience with each of these technologies. The approaches discussed here are being intensely pursued in terms of possible therapeutic applications. However, we will restrict our comments primarily to the cell culture situation, only briefly alluding to fundamental differences between utilization in animals versus cells.

scholarly journals Histone demethylome map reveals combinatorial gene regulatory functions in embryonic stem cells

2020 ◽  
Author(s):  
Yogesh Kumar ◽  
Pratibha Tripathi ◽  
Majid Mehravar ◽  
Michael J. Bullen ◽  
Varun K. Pandey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Gene Regulation ◽  
Embryonic Stem Cells ◽  
Regulatory Network ◽  
Regulatory Networks ◽  
Target Gene ◽  
Embryonic Stem ◽  
Epigenetic Regulators ◽  
Regulatory Functions

SUMMARYEpigenetic regulators and transcription factors establish distinct regulatory networks for gene regulation to maintain the embryonic stem cells (ESC) state. Although much has been learned regarding individual epigenetic regulators, their combinatorial functions remain elusive. Here, we report combinatorial functions of histone demethylases (HDMs) in gene regulation of mouse ESCs that are currently unknown. We generated a histone demethylome (HDMome) map of 20 well-characterized HDMs based on their genome-wide binding. This revealed co-occupancy of HDMs in different combinations; predominantly, KDM1A-KDM4B-KDM6A and JARID2-KDM4A-KDM4C-KDM5B co-occupy at enhancers and promoters, respectively. Comprehensive mechanistic studies uncover that KDM1A-KDM6A combinatorially modulates P300/H3K27ac, H3K4me1, H3K4me2 deposition and OCT4 recruitment that eventually directs the OCT4/CORE regulatory network for target gene expression; while co-operative actions of JARID2-KDM4A-KDM4C-KDM5B control H2AK119ub1 and bivalent marks of polycomb-repressive complexes that facilitates the PRC regulatory network for target gene repression. Thus, combinatorial functions of HDMs impact gene expression programs to maintain the ESC state.

scholarly journals Network analysis identifies regulators of lineage-specific phenotypes in Mycobacterium tuberculosis

2020 ◽  
Author(s):  
Amir Banaei-Esfahani ◽  
Andrej Trauner ◽  
Sonia Borrell ◽  
Sebastian M. Gygli ◽  
Tige R. Rustad ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Mycobacterium Tuberculosis ◽  
Transcription Factors ◽  
List Type ◽  
Phylogenetic Distance ◽  
Clinical Strains ◽  
A Genome ◽  
L1 And L2 ◽  
Genome Scale

SummaryThe Mycobacterium tuberculosis (Mtb) complex comprises seven phylogenetically distinct human-adapted lineages exhibiting different geographical distribution and degrees of pathogenicity. Among these, Lineage 1 (L1) has been associated with low virulence whereas Lineage 2 (L2) has been linked to hyper-virulence, enhanced transmission and drug resistance. Here, we conducted multi-layer comparative analyses using whole genome sequencing data combined with quantitative transcriptomic and proteomic profiling of a set of L1 and L2 clinical strains, each grown under two different conditions in vitro. Our data revealed different degrees of correlation between transcript and protein abundances across clinical strains and functional gene categories, indicating variable levels of post-transcriptional regulation in the tested lineages. Contrasting genomic and gene expression data showed that the magnitude of the transcriptional and translational changes was proportional to the phylogenetic distance between strains, with one out of three single nucleotide polymorphisms leading to a transcriptional and/or translational change on average. We devised a new genome-scale transcriptional regulatory model and identified several master transcription factors, strongly linked to the sigma factor network, whose targets were differentially regulated between the two lineages. These differences resulted in a higher basal expression of DosR proteins and a stronger response to nitric oxide (NO) exposure in L2 compared to L1. These patterns are most likely responsible for the shorter NO-induced growth arrest in L2 observed. Given the limited genetic variation between strains, it appears that phenotypic differences in Mtb are substantially driven by differences in the regulation of biochemical networks through master transcriptional regulators.HighlightsProteomic and transcriptomic characterization of fully sequenced diverse L1 and L2 clinical isolates of Mtb.Post-transcriptional control mechanisms for regulatory and virulence genes are mitigated in Mtb L2.By applying a genome-scale transcriptional framework, DosR, Rv1985c, Lsr2 and Rv0691c are identified as master transcription factors responsible for differential target gene expression in L2 strains compared to L1.L1 and L2 DosR proteins respond differently to nitric oxide stress, thus determining a relevant phenotype.

scholarly journals Changes in ambient temperature are the prevailing cue in determining Brachypodium distachyon diurnal gene regulation

2019 ◽  
Author(s):  
Kirk J-M. MacKinnon ◽  
Benjamin J. Cole ◽  
Chang Yu ◽  
Joshua H. Coomey ◽  
Nolan T. Hartwick ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Circadian Clock ◽  
Clock Genes ◽  
Brachypodium Distachyon ◽  
Regulation Of Gene Expression ◽  
Enrichment Analysis ◽  
Grass Species ◽  
List Type ◽  
Sequence Motifs

SUMMARYPlants are continuously exposed to diurnal fluctuations in light and temperature, and spontaneous changes in their physical or biotic environment. The circadian clock coordinates regulation of gene expression with a 24-hour period, enabling the anticipation of these events.We used RNA sequencing to characterize the Brachypodium distachyon transcriptome under light and temperature cycles, as well as under constant conditions.Approximately 3% of the transcriptome was regulated by the circadian clock, a smaller proportion reported in most other species. For most transcripts that were rhythmic under all conditions, including many known clock genes, the period of gene expression lengthened from 24 to 27 h in the absence of external cues. To functionally characterize the cyclic transcriptome in B. distachyon, we used Gene Ontology enrichment analysis, and found several terms significantly associated with peak expression at particular times of the day. Furthermore we identified sequence motifs enriched in the promoters of similarly-phased genes, some potentially associated with transcription factors.When considering the overlap in rhythmic gene expression and specific pathway behavior, thermocycles was the prevailing cue that controlled diurnal gene regulation. Taken together, our characterization of the rhythmic B. distachyon transcriptome represents a foundational resource with implications in other grass species.

FLT3ITD Target Enhancers Are Primed but Inaccessible in Fetal Hematopoietic Progenitors

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1228-1228
Author(s):  
Yanan Li ◽  
Riddhi M Patel ◽  
Emily Casey ◽  
Jeffrey A. Magee
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Target Gene ◽  
Target Genes ◽  
Conflicts Of Interest ◽  
Gene Activation ◽  
Chromatin Accessibility ◽  
Luciferase Reporter ◽  
Enhancer Activity ◽  
Target Gene Expression

The FLT3 Internal Tandem Duplication (FLT3ITD) is common somatic mutation in acute myeloid leukemia (AML). We have previously shown that FLT3ITD fails to induce changes in HSC self-renewal, myelopoiesis and leukemogenesis during fetal stages of life. FLT3ITD signal transduction pathways are hyperactivated in fetal progenitors, but FLT3ITD target genes are not. This suggests that postnatal-specific transcription factors may be required to help induce FLT3ITD target gene expression. Alternatively, repressive histone modifications may impose a barrier to FLT3ITD target gene activation in fetal HPCs that is relaxed during postnatal development. To resolve these possibilities, we used ATAC-seq, as well as H3K4me1, H3K27ac and H3K27me3 ChIP-seq, to identify cis-elements that putatively control FLT3ITD target gene expression in fetal and adult hematopoietic progenitor cells (HPCs). We identified many enhancer elements (ATAC-seq peaks with H3K4me1 and H3K27ac) that exhibited increased chromatin accessibility and activity in FLT3ITD adult HPCs relative to wild type adult HPCs. These elements were enriched near FLT3ITD target genes. HOMER analysis showed enrichment for STAT5, ETS, RUNX1 and IRF binding motifs within the FLT3ITD target enhancers, but motifs for temporally dynamic transcription factors were not identified. We cloned a subset of the enhancers and confirmed that they could synergize with their promoter to activate a luciferase reporter. For representative enhancers, STAT5 binding sites were required to activate the enhancer - as anticipated - and RUNX1 repressed enhancer activity. We tested whether accessibility or priming changed between fetal and adult stages of HPC development. FLT3ITD-dependent changes in chromatin accessibility were not observed in fetal HPCs, though the enhancers were primed early in development as evidenced by the presence of H3K4me1. Repressive H3K27me3 were not present at FLT3ITD target enhancers in either or adult HPCs. The data show that FLT3ITD target enhancers are demarcated early in hematopoietic development, long before they become responsive to FLT3ITD signaling. Repressive marks do not appear to create an epigenetic barrier to enhancer activation in the fetal stage. Instead, age-specific transcription factors are likely required to pioneer enhancer elements so that they can respond to STAT5 and other FLT3ITD effectors. Disclosures No relevant conflicts of interest to declare.

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