scholarly journals Identification of the Regulatory Elements and Target Genes of Megakaryopoietic Transcription Factor MEF2C

2019 ◽  
Vol 119 (05) ◽  
pp. 716-725 ◽  
Author(s):  
Xianguo Kong ◽  
Lin Ma ◽  
Edward Chen ◽  
Chad Shaw ◽  
Leonard Edelstein
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Genetic Variation ◽  
Transcription Factors ◽  
Cell Fate ◽  
Target Genes ◽  
Regulatory Elements ◽  
Haematopoietic Stem Cells ◽  
Platelet Production ◽  
Induced Pluripotent

AbstractMegakaryopoiesis produces specialized haematopoietic stem cells in the bone marrow that give rise to megakaryocytes which ultimately produce platelets. Defects in megakaryopoiesis can result in altered platelet counts and physiology, leading to dysfunctional haemostasis and thrombosis. Additionally, dysregulated megakaryopoiesis is also associated with myeloid pathologies. Transcription factors play critical roles in cell differentiation by regulating the temporal and spatial patterns of gene expression which ultimately decide cell fate. Several transcription factors have been described as regulating megakaryopoiesis including myocyte enhancer factor 2C (MEF2C); however, the genes regulated by MEF2C that influence megakaryopoiesis have not been reported. Using chromatin immunoprecipitation-sequencing and Gene Ontology data we identified five candidate genes that are bound by MEF2C and regulate megakaryopoiesis: MOV10, AGO3, HDAC1, RBBP5 and WASF2. To study expression of these genes, we silenced MEF2C gene expression in the Meg01 megakaryocytic cell line and in induced pluripotent stem cells by CRISPR/Cas9 editing. We also knocked down MEF2C expression in cord blood-derived haematopoietic stem cells by siRNA. We found that absent or reduced MEF2C expression resulted in defects in megakaryocytic differentiation and reduced levels of the candidate target genes. Luciferase assays confirmed that genomic sequences within the target genes are regulated by MEF2C levels. Finally, we demonstrate that small deletions linked to a platelet count-associated single nucleotide polymorphism alter transcriptional activity, suggesting a mechanism by which genetic variation in MEF2C alters platelet production. These data help elucidate the mechanism behind MEF2C regulation of megakaryopoiesis and genetic variation driving platelet production.

scholarly journals Noncoding de novo mutations contribute to autism spectrum disorder via chromatin interactions

2019 ◽  
Author(s):  
Il Bin Kim ◽  
Taeyeop Lee ◽  
Junehawk Lee ◽  
Jonghun Kim ◽  
Hyunseong Lee ◽  
...  
Keyword(s):  
Gene Expression ◽  
Autism Spectrum Disorder ◽  
Stem Cells ◽  
Target Genes ◽  
De Novo ◽  
Regulatory Elements ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
De Novo Mutations ◽  
Chromatin Interactions

Three-dimensional chromatin structures regulate gene expression across genome. The significance of de novo mutations (DNMs) affecting chromatin interactions in autism spectrum disorder (ASD) remains poorly understood. We generated 931 whole-genome sequences for Korean simplex families to detect DNMs and identified target genes dysregulated by noncoding DNMs via long-range chromatin interactions between regulatory elements. Notably, noncoding DNMs that affect chromatin interactions exhibited transcriptional dysregulation implicated in ASD risks. Correspondingly, target genes were significantly involved in histone modification, prenatal brain development, and pregnancy. Both noncoding and coding DNMs collectively contributed to low IQ in ASD. Indeed, noncoding DNMs resulted in alterations, via chromatin interactions, in target gene expression in primitive neural stem cells derived from human induced pluripotent stem cells from an ASD subject. The emerging neurodevelopmental genes, not previously implicated in ASD, include CTNNA2, GRB10, IKZF1, PDE3B, and BACE1. Our results were reproducible in 517 probands from MSSNG cohort. This work demonstrates that noncoding DNMs contribute to ASD via chromatin interactions.

scholarly journals Genetic control of pluripotency epigenome determines differentiation bias in mouse embryonic stem cells

2021 ◽  
Author(s):  
Candice Byers ◽  
Catrina Spruce ◽  
Haley J. Fortin ◽  
Anne Czechanski ◽  
Steven C. Munger ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Cell Fate ◽  
Genetic Regulation ◽  
Embryonic Stem ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Embryoid Bodies ◽  
Cell Fate Decisions

AbstractGenetically diverse pluripotent stem cells (PSCs) display varied, heritable responses to differentiation cues in the culture environment. By harnessing these disparities through derivation of embryonic stem cells (ESCs) from the BXD mouse genetic reference panel, along with C57BL/6J (B6) and DBA/2J (D2) parental strains, we demonstrate genetically determined biases in lineage commitment and identify major regulators of the pluripotency epigenome. Upon transition to formative pluripotency using epiblast-like cells (EpiLCs), B6 quickly dissolves naïve networks adopting gene expression modules indicative of neuroectoderm lineages; whereas D2 retains aspects of naïve pluripotency with little bias in differentiation. Genetic mapping identifies 6 major trans-acting loci co-regulating chromatin accessibility and gene expression in ESCs and EpiLCs, indicating a common regulatory system impacting cell state transition. These loci distally modulate occupancy of pluripotency factors, including TRIM28, P300, and POU5F1, at hundreds of regulatory elements. One trans-acting locus on Chr 12 primarily impacts chromatin accessibility in ESCs; while in EpiLCs the same locus subsequently influences gene expression, suggesting early chromatin priming. Consequently, the distal gene targets of this locus are enriched for neurogenesis genes and were more highly expressed when cells carried B6 haplotypes at this Chr 12 locus, supporting genetic regulation of biases in cell fate. Spontaneous formation of embryoid bodies validated this with B6 showing a propensity towards neuroectoderm differentiation and D2 towards definitive endoderm, confirming the fundamental importance of genetic variation influencing cell fate decisions.

scholarly journals Cis acting variation is common, can propagates across multiple regulatory layers, but is often buffered in developmental programs

2020 ◽  
Author(s):  
Swann Floc’hlay ◽  
Emily Wong ◽  
Bingqing Zhao ◽  
Rebecca R. Viales ◽  
Morgane Thomas-Chollier ◽  
...  
Keyword(s):  
Gene Expression ◽  
Genetic Variation ◽  
Transcription Factors ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Cis Acting ◽  
Dna Mutations ◽  
Allele Specific ◽  
Regulatory Dna ◽  
The Impact

AbstractPrecise patterns of gene expression are driven by interactions between transcription factors, regulatory DNA sequence, and chromatin. How DNA mutations affecting any one of these regulatory ‘layers’ is buffered or propagated to gene expression remains unclear. To address this, we quantified allele-specific changes in chromatin accessibility, histone modifications, and gene expression in F1 embryos generated from eight Drosophila crosses, at three embryonic stages, yielding a comprehensive dataset of 240 samples spanning multiple regulatory layers. Genetic variation in cis-regulatory elements is common, highly heritable, and surprisingly consistent in its effects across embryonic stages. Much of this variation does not propagate to gene expression. When it does, it acts through H3K4me3 or alternatively through chromatin accessibility and H3K27ac. The magnitude and evolutionary impact of mutations is influenced by a genes’ regulatory complexity (i.e. enhancer number), with transcription factors being most robust to cis-acting, and most influenced by trans-acting, variation. Overall, the impact of genetic variation on regulatory phenotypes appears context-dependent even within the constraints of embryogenesis.

scholarly journals Transcription factors orchestrate dynamic interplay between genome topology and gene regulation during cell reprogramming

2017 ◽  
Author(s):  
Ralph Stadhouders ◽  
Enrique Vidal ◽  
François Serra ◽  
Bruno Di Stefano ◽  
François Le Dily ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Transcription Factors ◽  
Cell Fate ◽  
Pluripotent Stem Cells ◽  
Time Resolved ◽  
Genome Reorganization ◽  
Chromosomal Architecture ◽  
Dynamic Interplay ◽  
Pluripotency Genes

ABSTRACTChromosomal architecture is known to influence gene expression, yet its role in controlling cell fate remains poorly understood. Reprogramming of somatic cells into pluripotent stem cells by the transcription factors (TFs) Oct4, Sox2, Klf4 and Myc offers an opportunity to address this question but is severely limited by the low proportion of responding cells. We recently developed a highly efficient reprogramming protocol that synchronously converts somatic into pluripotent stem cells. Here, we employ this system to integrate time-resolved changes in genome topology with gene expression, TF binding and chromatin state dynamics. This revealed that TFs drive topological genome reorganization at multiple architectural levels, which often precedes changes in gene expression. Removal of locus-specific topological barriers can explain why pluripotency genes are activated sequentially, instead of simultaneously, during reprogramming. Taken together, our study implicates genome topology as an instructive force for implementing transcriptional programs and cell fate in mammals.

scholarly journals Discovery and characterization of variance QTLs in human induced pluripotent stem cells

2018 ◽  
Author(s):  
Abhishek K. Sarkar ◽  
Po-Yuan Tung ◽  
John D. Blischak ◽  
Jonathan E. Burnett ◽  
Yang I. Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Genetic Variation ◽  
Single Cell ◽  
Pluripotent Stem Cells ◽  
Human Tissues ◽  
Rna Seq ◽  
Induced Pluripotent ◽  
Expression Variance ◽  
Gene Expression Levels

AbstractQuantification of gene expression levels at the single cell level has revealed that gene expression can vary substantially even across a population of homogeneous cells. However, it is currently unclear what genomic features control variation in gene expression levels, and whether common genetic variants may impact gene expression variation. Here, we take a genome-wide approach to identify expression variance quantitative trait loci (vQTLs). To this end, we generated single cell RNA-seq (scRNA-seq) data from induced pluripotent stem cells (iPSCs) derived from 53 Yoruba individuals. We collected data for a median of 95 cells per individual and a total of 5,447 single cells, and identified 241 mean expression QTLs (eQTLs) at 10% FDR, of which 82% replicate in bulk RNA-seq data from the same individuals. We further identified 14 vQTLs at 10% FDR, but demonstrate that these can also be explained as effects on mean expression. Our study suggests that dispersion QTLs (dQTLs) which could alter the variance of expression independently of the mean can have larger fold changes, but explain less phenotypic variance than eQTLs. We estimate 424 individuals as a lower bound to achieve 80% power to detect the strongest dQTLs in iPSCs. These results will guide the design of future studies on understanding the genetic control of gene expression variance.Author summaryCommon genetic variation can alter the level of average gene expression in human tissues, and through changes in gene expression have downstream consequences on cell function, human development, and human disease. However, human tissues are composed of many cells, each with its own level of gene expression. With advances in single cell sequencing technologies, we can now go beyond simply measuring the average level of gene expression in a tissue sample and directly measure cell-to-cell variance in gene expression. We hypothesized that genetic variation could also alter gene expression variance, potentially revealing new insights into human development and disease. To test this hypothesis, we used single cell RNA sequencing to directly measure gene expression variance in multiple individuals, and then associated the gene expression variance with genetic variation in those same individuals. Our results suggest that effects on gene expression variance are smaller than effects on mean expression, relative to how much the phenotypes vary between individuals, and will require much larger studies than previously thought to detect.

scholarly journals Large-Scale Profiling Reveals the Influence of Genetic Variation on Gene Expression in Human Induced Pluripotent Stem Cells

2017 ◽  
Vol 20 (4) ◽  
pp. 533-546.e7 ◽  
Author(s):  
Christopher DeBoever ◽  
He Li ◽  
David Jakubosky ◽  
Paola Benaglio ◽  
Joaquin Reyna ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Genetic Variation ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Large Scale ◽  
Induced Pluripotent

scholarly journals Single cell eQTL analysis identifies cell type-specific genetic control of gene expression in fibroblasts and reprogrammed induced pluripotent stem cells

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Drew Neavin ◽  
Quan Nguyen ◽  
Maciej S. Daniszewski ◽  
Helena H. Liang ◽  
Han Sheng Chiu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Population Genetics ◽  
Genetic Variation ◽  
Single Cell ◽  
Pluripotent Stem Cells ◽  
Individual Cell ◽  
Cell Type ◽  
Cell Type Specific ◽  
Induced Pluripotent

Abstract Background The discovery that somatic cells can be reprogrammed to induced pluripotent stem cells (iPSCs) has provided a foundation for in vitro human disease modelling, drug development and population genetics studies. Gene expression plays a critical role in complex disease risk and therapeutic response. However, while the genetic background of reprogrammed cell lines has been shown to strongly influence gene expression, the effect has not been evaluated at the level of individual cells which would provide significant resolution. By integrating single cell RNA-sequencing (scRNA-seq) and population genetics, we apply a framework in which to evaluate cell type-specific effects of genetic variation on gene expression. Results Here, we perform scRNA-seq on 64,018 fibroblasts from 79 donors and map expression quantitative trait loci (eQTLs) at the level of individual cell types. We demonstrate that the majority of eQTLs detected in fibroblasts are specific to an individual cell subtype. To address if the allelic effects on gene expression are maintained following cell reprogramming, we generate scRNA-seq data in 19,967 iPSCs from 31 reprogramed donor lines. We again identify highly cell type-specific eQTLs in iPSCs and show that the eQTLs in fibroblasts almost entirely disappear during reprogramming. Conclusions This work provides an atlas of how genetic variation influences gene expression across cell subtypes and provides evidence for patterns of genetic architecture that lead to cell type-specific eQTL effects.

scholarly journals PRMT6 activates cyclin D1 expression in conjunction with the transcription factor LEF1

Oncogenesis ◽  
2021 ◽  
Vol 10 (5) ◽  
Author(s):  
Lucas Schneider ◽  
Stefanie Herkt ◽  
Lei Wang ◽  
Christine Feld ◽  
Josephine Wesely ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Transcription Factors ◽  
Cyclin D1 ◽  
Cell Fate ◽  
Target Genes ◽  
Specific Gene ◽  
Cell Fate Decisions ◽  
Rational Development ◽  
Differentiation And Proliferation

AbstractThe establishment of cell type specific gene expression by transcription factors and their epigenetic cofactors is central for cell fate decisions. Protein arginine methyltransferase 6 (PRMT6) is an epigenetic regulator of gene expression mainly through methylating arginines at histone H3. This way it influences cellular differentiation and proliferation. PRMT6 lacks DNA-binding capability but is recruited by transcription factors to regulate gene expression. However, currently only a limited number of transcription factors have been identified, which facilitate recruitment of PRMT6 to key cell cycle related target genes. Here, we show that LEF1 contributes to the recruitment of PRMT6 to the central cell cycle regulator CCND1 (Cyclin D1). We identified LEF1 as an interaction partner of PRMT6. Knockdown of LEF1 or PRMT6 reduces CCND1 expression. This is in line with our observation that knockdown of PRMT6 increases the number of cells in G1 phase of the cell cycle and decreases proliferation. These results improve the understanding of PRMT6 activity in cell cycle regulation. We expect that these insights will foster the rational development and usage of specific PRMT6 inhibitors for cancer therapy.

scholarly journals Enhancer priming by H3K4 methyltransferase MLL4 controls cell fate transition

2016 ◽  
Vol 113 (42) ◽  
pp. 11871-11876 ◽  
Author(s):  
Chaochen Wang ◽  
Ji-Eun Lee ◽  
Binbin Lai ◽  
Todd S. Macfarlan ◽  
Shiliyang Xu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Cell Fate ◽  
Control Cell ◽  
Embryonic Stem ◽  
Specific Gene ◽  
Cell Identity ◽  
Identity Maintenance ◽  
Cell Type Specific ◽  
Induced Pluripotent

Transcriptional enhancers control cell-type–specific gene expression. Primed enhancers are marked by histone H3 lysine 4 (H3K4) mono/di-methylation (H3K4me1/2). Active enhancers are further marked by H3K27 acetylation (H3K27ac). Mixed-lineage leukemia 4 (MLL4/KMT2D) is a major enhancer H3K4me1/2 methyltransferase with functional redundancy with MLL3 (KMT2C). However, its role in cell fate maintenance and transition is poorly understood. Here, we show in mouse embryonic stem cells (ESCs) that MLL4 associates with, but is surprisingly dispensable for the maintenance of, active enhancers of cell-identity genes. As a result, MLL4 is dispensable for cell-identity gene expression and self-renewal in ESCs. In contrast, MLL4 is required for enhancer-binding of H3K27 acetyltransferase p300, enhancer activation, and induction of cell-identity genes during ESC differentiation. MLL4 protein, rather than MLL4-mediated H3K4 methylation, controls p300 recruitment to enhancers. We also show that, in somatic cells, MLL4 is dispensable for maintaining cell identity but essential for reprogramming into induced pluripotent stem cells. These results indicate that, although enhancer priming by MLL4 is dispensable for cell-identity maintenance, it controls cell fate transition by orchestrating p300-mediated enhancer activation.

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