scholarly journals Computer and Statistical Analysis of Transcription Factor Binding and Chromatin Modifications by ChIP-seq data in Embryonic Stem Cell

2012 ◽  
Vol 9 (2) ◽  
pp. 88-100 ◽  
Author(s):  
Yuriy Orlov ◽  
Han Xu ◽  
Dmitri Afonnikov ◽  
Bing Lim ◽  
Jian-Chien Heng ◽  
...  

Summary Advances in high throughput sequencing technology have enabled the identification of transcription factor (TF) binding sites in genome scale. TF binding studies are important for medical applications and stem cell research. Somatic cells can be reprogrammed to a pluripotent state by the combined introduction of factors such as Oct4, Sox2, c-Myc, Klf4. These reprogrammed cells share many characteristics with embryonic stem cells (ESCs) and are known as induced pluripotent stem cells (iPSCs). The signaling requirements for maintenance of human and murine embryonic stem cells (ESCs) differ considerably. Genome wide ChIP-seq TF binding maps in mouse stem cells include Oct4, Sox2, Nanog, Tbx3, Smad2 as well as group of other factors. ChIP-seq allows study of new candidate transcription factors for reprogramming. It was shown that Nr5a2 could replace Oct4 for reprogramming. Epigenetic modifications play important role in regulation of gene expression adding additional complexity to transcription network functioning. We have studied associations between different histone modification using published data together with RNA Pol II sites. We found strong associations between activation marks and TF binding sites and present it qualitatively. To meet issues of statistical analysis of genome ChIP-sequencing maps we developed computer program to filter out noise signals and find significant association between binding site affinity and number of sequence reads. The data provide new insights into the function of chromatin organization and regulation in stem cells.

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Dana M King ◽  
Clarice Kit Yee Hong ◽  
James L Shepherdson ◽  
David M Granas ◽  
Brett B Maricque ◽  
...  

In embryonic stem cells (ESCs), a core transcription factor (TF) network establishes the gene expression program necessary for pluripotency. To address how interactions between four key TFs contribute to cis-regulation in mouse ESCs, we assayed two massively parallel reporter assay (MPRA) libraries composed of binding sites for SOX2, POU5F1 (OCT4), KLF4, and ESRRB. Comparisons between synthetic cis-regulatory elements and genomic sequences with comparable binding site configurations revealed some aspects of a regulatory grammar. The expression of synthetic elements is influenced by both the number and arrangement of binding sites. This grammar plays only a small role for genomic sequences, as the relative activities of genomic sequences are best explained by the predicted occupancy of binding sites, regardless of binding site identity and positioning. Our results suggest that the effects of transcription factor binding sites (TFBS) are influenced by the order and orientation of sites, but that in the genome the overall occupancy of TFs is the primary determinant of activity.


Blood ◽  
2009 ◽  
Vol 114 (1) ◽  
pp. 60-63 ◽  
Author(s):  
Kimi Y. Kong ◽  
Elizabeth A. Williamson ◽  
Jason H. Rogers ◽  
Tam Tran ◽  
Robert Hromas ◽  
...  

Abstract In embryonic stem cells, Oct-4 concentration is critical in determining the development of endoderm, mesoderm, and trophectoderm. Although Oct-4 expression is essential for mesoderm development, it is unclear whether it has a role in the development of specific mesodermal tissues. In this study, we have examined the importance of Oct-4 in the generation of hematopoietic cells using an inducible Oct-4 ESC line. We demonstrate that Oct-4 has a role in supporting hematopoiesis after specifying brachyury-positive mesoderm. When we suppressed Oct-4 expression before or after mesoderm specification, no hematopoietic cells are detected. However, hematopoiesis can be rescued in the absence of Oct-4 after mesoderm specification if the essential hematopoietic transcription factor stem cell leukemia is expressed. Our results suggest that, for hematopoiesis to occur, Oct-4 is required for the initial specification of mesoderm and subsequently is required for the development of hematopoietic cells from uncommitted mesoderm.


2021 ◽  
Author(s):  
Deepika Puri ◽  
Birgit Koschorz ◽  
Bettina Engist ◽  
Megumi Onishi-Seebacher ◽  
Devon Ryan ◽  
...  

Repeat element transcription plays a vital role in early embryonic development. Expression of repeats such as MERVL characterises mouse embryos at the 2-cell stage, and defines a 2-cell-like cell (2CLC) population in a mouse embryonic stem cell culture. Repeat element sequences contain binding sites for numerous transcription factors. We identify the forkhead domain transcription factor FOXD3 as a regulator of repeat element transcription in mouse embryonic stem cells. FOXD3 binds to and recruits the histone methyltransferase SUV39H1 to MERVL and major satellite repeats, consequentially repressing the transcription of these repeats by the establishment of the H3K9me3 heterochromatin modification. Notably, depletion of FOXD3 leads to the de-repression of MERVL and major satellite repeats as well as a subset of genes expressed in the 2-cell state, shifting the balance between the stem cell and 2 cell-like population in culture. Thus, FOXD3 acts as a negative regulator of repeat transcription, ascribing a novel function to this transcription factor.


Author(s):  
Gurdeep Singh ◽  
Shanelle Mullany ◽  
Sakthi D Moorthy ◽  
Richard Zhang ◽  
Tahmid Mehdi ◽  
...  

ABSTRACTTranscriptional enhancers are critical for development, phenotype evolution and often mutated in disease contexts; however, even in well-studied cell types, the sequence code conferring enhancer activity remains unknown. We found genomic regions with conserved binding of multiple transcription factors in mouse and human embryonic stem cells (ESCs) contain on average 12.6 conserved transcription factor binding sites (TFBS). These TFBS are a diverse repertoire of 70 different sequences representing the binding sites of both known and novel ESC regulators. Remarkably, using a diverse set of TFBS from this repertoire was sufficient to construct short synthetic enhancers with activity comparable to native enhancers. Site directed mutagenesis of conserved TFBS in endogenous enhancers or TFBS deletion from synthetic sequences revealed a requirement for more than ten different TFBS. Furthermore, specific TFBS, including the OCT4:SOX2 co-motif, are dispensable, despite co-binding the OCT4, SOX2 and NANOG master regulators of pluripotency. These findings reveal a TFBS diversity threshold overrides the need for optimized regulatory grammar and individual TFBS that bind specific master regulators.


2021 ◽  
Vol 22 (9) ◽  
pp. 5011
Author(s):  
Daehwan Kim ◽  
Sangho Roh

Stem cell research is essential not only for the research and treatment of human diseases, but also for the genetic preservation and improvement of animals. Since embryonic stem cells (ESCs) were established in mice, substantial efforts have been made to establish true ESCs in many species. Although various culture conditions were used to establish ESCs in cattle, the capturing of true bovine ESCs (bESCs) has not been achieved. In this review, the difficulty of establishing bESCs with various culture conditions is described, and the characteristics of proprietary induced pluripotent stem cells and extended pluripotent stem cells are introduced. We conclude with a suggestion of a strategy for establishing true bESCs.


2010 ◽  
Vol 289 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Shaker A. Mousa ◽  
Thangirala Sudha ◽  
Evgeny Dyskin ◽  
Usawadee Dier ◽  
Christine Gallati ◽  
...  

1994 ◽  
Vol 14 (5) ◽  
pp. 3108-3114
Author(s):  
M H Baron ◽  
S M Farrington

The zinc finger transcription factor GATA-1 is a major regulator of gene expression in erythroid, megakaryocyte, and mast cell lineages. GATA-1 binds to WGATAR consensus motifs in the regulatory regions of virtually all erythroid cell-specific genes. Analyses with cultured cells and cell-free systems have provided strong evidence that GATA-1 is involved in control of globin gene expression during erythroid differentiation. Targeted mutagenesis of the GATA-1 gene in embryonic stem cells has demonstrated its requirement in normal erythroid development. Efficient rescue of the defect requires an intact GATA element in the distal promoter, suggesting autoregulatory control of GATA-1 transcription. To examine whether GATA-1 expression involves additional regulatory factors or is maintained entirely by an autoregulatory loop, we have used a transient heterokaryon system to test the ability of erythroid factors to activate the GATA-1 gene in nonerythroid nuclei. We show here that proerythroblasts and mature erythroid cells contain a diffusible activity (TAG) capable of transcriptional activation of GATA-1 and that this activity decreases during the terminal differentiation of erythroid cells. Nuclei from GATA-1- mutant embryonic stem cells can still be reprogrammed to express their globin genes in erythroid heterokaryons, indicating that de novo induction of GATA-1 is not required for globin gene activation following cell fusion.


1989 ◽  
Vol 9 (10) ◽  
pp. 4563-4567
Author(s):  
T H Vu ◽  
G R Martin ◽  
P Lee ◽  
D Mark ◽  
A Wang ◽  
...  

Embryonal carcinoma and embryonic stem cells expressed a novel form of platelet-derived growth factor receptor mRNA which was approximately 1,100 base pairs shorter than the 5.3-kilobase (kb) transcript expressed in fibroblasts and other cell types. The 4.2-kb stem cell transcript was initiated within the genomic region immediately upstream of exon 6 of the 5.3-kb transcript and therefore lacked the first five exons, which encode much of the extracellular domain of the receptor expressed in fibroblasts. In stem cells, the short form was predominant, although both forms were present at low levels. Following differentiation in vitro, expression levels of the long form increased dramatically. These findings suggest that during early embryogenesis, a stem cell-specific promoter is used in a stage- and cell type-specific manner to express a form of the platelet-derived growth factor receptor that lacks much of the extracellular domain and may function independently of ligand.


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