scholarly journals Identifying regulators of parental imprinting by CRISPR/Cas9 screening in haploid human embryonic stem cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shiran Bar ◽  
Dan Vershkov ◽  
Gal Keshet ◽  
Elyad Lezmi ◽  
Naama Meller ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Dna Demethylation ◽  
Human Embryos ◽  
Monoallelic Expression ◽  
Imprinted Genes ◽  
Genome Wide ◽  
A Genome ◽  
Parental Imprinting

AbstractIn mammals, imprinted genes are regulated by differentially methylated regions (DMRs) that are inherited from germ cells, leading to monoallelic expression in accordance with parent-of-origin. Yet, it is largely unknown how imprinted DMRs are maintained in human embryos despite global DNA demethylation following fertilization. Here, we explored the mechanisms involved in imprinting regulation by employing human parthenogenetic embryonic stem cells (hpESCs), which lack paternal alleles. We show that although global loss of DNA methylation in hpESCs affects most imprinted DMRs, many paternally-expressed genes (PEGs) remain repressed. To search for factors regulating PEGs, we performed a genome-wide CRISPR/Cas9 screen in haploid hpESCs. This revealed ATF7IP as an essential repressor of a set of PEGs, which we further show is also required for silencing sperm-specific genes. Our study reinforces an important role for histone modifications in regulating imprinted genes and suggests a link between parental imprinting and germ cell identity.

scholarly journals A genome-wide RNAi screen in mouse embryonic stem cells identifies Mp1 as a key mediator of differentiation

2011 ◽  
Vol 195 (6) ◽  
pp. i9-i9 ◽  
Author(s):  
Bart A. Westerman ◽  
A. Koen Braat ◽  
Nicole Taub ◽  
Marko Potman ◽  
Joseph H.A. Vissers ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cells ◽  
Rnai Screen ◽  
Genome Wide ◽  
A Genome

scholarly journals STARR-seq identifies active, chromatin-masked, and dormant enhancers in pluripotent mouse embryonic stem cells

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Tianran Peng ◽  
Yanan Zhai ◽  
Yaser Atlasi ◽  
Menno ter Huurne ◽  
Hendrik Marks ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Cell Fate ◽  
Control Cell ◽  
Embryonic Stem ◽  
Chromatin Accessibility ◽  
Mouse Embryonic Stem Cells ◽  
Chromatin Signature ◽  
Genome Wide ◽  
A Genome

Abstract Background Enhancers are distal regulators of gene expression that shape cell identity and control cell fate transitions. In mouse embryonic stem cells (mESCs), the pluripotency network is maintained by the function of a complex network of enhancers, that are drastically altered upon differentiation. Genome-wide chromatin accessibility and histone modification assays are commonly used as a proxy for identifying putative enhancers and for describing their activity levels and dynamics. Results Here, we applied STARR-seq, a genome-wide plasmid-based assay, as a read-out for the enhancer landscape in “ground-state” (2i+LIF; 2iL) and “metastable” (serum+LIF; SL) mESCs. This analysis reveals that active STARR-seq loci show modest overlap with enhancer locations derived from peak calling of ChIP-seq libraries for common enhancer marks. We unveil ZIC3-bound loci with significant STARR-seq activity in SL-ESCs. Knock-out of Zic3 removes STARR-seq activity only in SL-ESCs and increases their propensity to differentiate towards the endodermal fate. STARR-seq also reveals enhancers that are not accessible, masked by a repressive chromatin signature. We describe a class of dormant, p53 bound enhancers that gain H3K27ac under specific conditions, such as after treatment with Nocodazol, or transiently during reprogramming from fibroblasts to pluripotency. Conclusions In conclusion, loci identified as active by STARR-seq often overlap with those identified by chromatin accessibility and active epigenetic marking, yet a significant fraction is epigenetically repressed or display condition-specific enhancer activity.

scholarly journals Embryoid research calls for reassessment of legal regulations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Markus Hengstschläger ◽  
Margit Rosner
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Human Embryonic Stem Cells ◽  
Legal Status ◽  
Embryonic Stem ◽  
Basic Research ◽  
Human Embryos ◽  
Human Being ◽  
Legal Regulations ◽  
Definition Of

AbstractIt is known that in countries, in which basic research on human embryos is in fact prohibited by law, working with imported human embryonic stem cells (hESCs) can still be permitted. As long as hESCs are not capable of development into a complete human being, it might be the case that they do not fulfill all criteria of the local definition of an embryo. Recent research demonstrates that hESCs can be developed into entities, called embryoids, which increasingly could come closer to actual human embryos in future. By discussing the Austrian situation, we want to highlight that current embryoid research could affect the prevailing opinion on the legal status of work with hESCs and therefore calls for reassessment of the regulations in all countries with comparable definitions of the embryo.

Regenerative Medicine: Applications and Development in Urology

2007 ◽  
Vol 74 (4) ◽  
pp. 197-205
Author(s):  
F. Pinto ◽  
A. Calarco ◽  
A. Brescia ◽  
E. Sacco ◽  
A. D'addessi ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Regenerative Medicine ◽  
Cell Transplantation ◽  
Materials Science ◽  
Experimental Studies ◽  
Embryonic Stem ◽  
Human Embryos ◽  
Engineering Applications

Purpose Congenital abnormalities and acquired disorders can lead to organ damage and loss. Nowadays, transplantation represents the only effective treatment option. However, there is a marked decrease in the number of organ donors, which is even yearly worsening due to the population aging. The regenerative medicine represents a realistic option that allows to restore and maintain the normal functions of tissues and organs. This article reviews the principles of regenerative medicine and the recent advances with regard to its application to the genitourinary tract. Recent findings The field of regenerative medicine involves different areas of technology, such as tissue engineering, stem cells and cloning. Tissue engineering involves the field of cell transplantation, materials science and engineering in order to create functional replacement tissues. Stem cells and cloning permit the extraction of pluripotent, embryonic stem cells offering a potentially limitless source of cells for tissue engineering applications. Most current strategies for tissue engineering depend upon a sample of autologous cells from the patient's diseased organ. Biopsies from patients with extensive end-stage organ failure, however, may not yield enough normal cells. In these situations, stem cells are envisaged as being an alternative source. Stem cells can be derived from discarded human embryos (human embryonic stem cells), from fetal tissue or from adult sources (bone marrow, fat, skin). Therapeutic cloning offers a potentially limitless source of cells for tissue engineering applications. Regenerative medicine and tissue engineering scientists have increasingly applied the principles of cell transplantation, materials science and bioengineering to construct biological substitutes that will restore and maintain normal function in urological diseased and injured tissues such as kidney, ureter, bladder, urethra and penis. Conclusions Regenerative medicine offers several applications in acquired and congenital genitourinary diseases. Tissue engineering, stem cells and, mostly, cloning have been applied in experimental studies with excellent results. Few preliminary human applications have been developed with promising results.

scholarly journals Genome-Wide Definition of Promoter and Enhancer Usage during Neural Induction of Human Embryonic Stem Cells

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0126590 ◽  
Author(s):  
Valentina Poletti ◽  
Alessia Delli Carri ◽  
Guidantonio Malagoli Tagliazucchi ◽  
Andrea Faedo ◽  
Luca Petiti ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Neural Induction ◽  
Genome Wide ◽  
Wide Definition ◽  
Definition Of

scholarly journals Genome-wide mapping of 5-hydroxymethylcytosine in embryonic stem cells

Nature ◽  
2011 ◽  
Vol 473 (7347) ◽  
pp. 394-397 ◽  
Author(s):  
William A. Pastor ◽  
Utz J. Pape ◽  
Yun Huang ◽  
Hope R. Henderson ◽  
Ryan Lister ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Genome Wide
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