Resetting Cell Fate by Epigenetic Reprogramming

Author(s):  
Molly Pui Man Wong ◽  
Ray Kit Ng
2018 ◽  
Vol 218 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Sabrina Ladstätter ◽  
Kikuë Tachibana

The early embryo is the natural prototype for the acquisition of totipotency, which is the potential of a cell to produce a whole organism. Generation of a totipotent embryo involves chromatin reorganization and epigenetic reprogramming that alter DNA and histone modifications. Understanding embryonic chromatin architecture and how this is related to the epigenome and transcriptome will provide invaluable insights into cell fate decisions. Recently emerging low-input genomic assays allow the exploration of regulatory networks in the sparsely available mammalian embryo. Thus, the field of developmental biology is transitioning from microscopy to genome-wide chromatin descriptions. Ultimately, the prototype becomes a unique model for studying fundamental principles of development, epigenetic reprogramming, and cellular plasticity. In this review, we discuss chromatin reprogramming in the early mouse embryo, focusing on DNA methylation, chromatin accessibility, and higher-order chromatin structure.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yun Ji ◽  
Jessica Fioravanti ◽  
Wei Zhu ◽  
Hongjun Wang ◽  
Tuoqi Wu ◽  
...  

2013 ◽  
Vol 368 (1609) ◽  
pp. 20110330 ◽  
Author(s):  
Stefanie Seisenberger ◽  
Julian R. Peat ◽  
Timothy A. Hore ◽  
Fátima Santos ◽  
Wendy Dean ◽  
...  

In mammalian development, epigenetic modifications, including DNA methylation patterns, play a crucial role in defining cell fate but also represent epigenetic barriers that restrict developmental potential. At two points in the life cycle, DNA methylation marks are reprogrammed on a global scale, concomitant with restoration of developmental potency. DNA methylation patterns are subsequently re-established with the commitment towards a distinct cell fate. This reprogramming of DNA methylation takes place firstly on fertilization in the zygote, and secondly in primordial germ cells (PGCs), which are the direct progenitors of sperm or oocyte. In each reprogramming window, a unique set of mechanisms regulates DNA methylation erasure and re-establishment. Recent advances have uncovered roles for the TET3 hydroxylase and passive demethylation, together with base excision repair (BER) and the elongator complex, in methylation erasure from the zygote. Deamination by AID, BER and passive demethylation have been implicated in reprogramming in PGCs, but the process in its entirety is still poorly understood. In this review, we discuss the dynamics of DNA methylation reprogramming in PGCs and the zygote, the mechanisms involved and the biological significance of these events. Advances in our understanding of such natural epigenetic reprogramming are beginning to aid enhancement of experimental reprogramming in which the role of potential mechanisms can be investigated in vitro . Conversely, insights into in vitro reprogramming techniques may aid our understanding of epigenetic reprogramming in the germline and supply important clues in reprogramming for therapies in regenerative medicine.


2011 ◽  
Vol 366 (1575) ◽  
pp. 2266-2273 ◽  
Author(s):  
Petra Hajkova

Epigenetic reprogramming in the germline provides a developmental model to study the erasure of epigenetic memory as it occurs naturally in vivo in the course of normal embryonic development. Our data show that germline reprogramming comprises both active DNA demethylation and extensive chromatin remodelling that are mechanistically linked through the activation of the base excision DNA repair pathway involved in the DNA demethylation process. The observed molecular hallmarks of the germline reprogramming exhibit intriguing similarities to other dedifferentiation or regeneration systems, pointing towards the existence of unifying molecular pathways underlying cell fate reversal. Elucidation of molecular processes involved in the resetting of epigenetic information in vivo will thus add to our ability to manipulate cell fate and to restore pluripotency in in vitro settings.


2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.


2020 ◽  
Vol 64 (2) ◽  
pp. 223-232 ◽  
Author(s):  
Ben L. Carty ◽  
Elaine M. Dunleavy

Abstract Asymmetric cell division (ACD) produces daughter cells with separate distinct cell fates and is critical for the development and regulation of multicellular organisms. Epigenetic mechanisms are key players in cell fate determination. Centromeres, epigenetically specified loci defined by the presence of the histone H3-variant, centromere protein A (CENP-A), are essential for chromosome segregation at cell division. ACDs in stem cells and in oocyte meiosis have been proposed to be reliant on centromere integrity for the regulation of the non-random segregation of chromosomes. It has recently been shown that CENP-A is asymmetrically distributed between the centromeres of sister chromatids in male and female Drosophila germline stem cells (GSCs), with more CENP-A on sister chromatids to be segregated to the GSC. This imbalance in centromere strength correlates with the temporal and asymmetric assembly of the mitotic spindle and potentially orientates the cell to allow for biased sister chromatid retention in stem cells. In this essay, we discuss the recent evidence for asymmetric sister centromeres in stem cells. Thereafter, we discuss mechanistic avenues to establish this sister centromere asymmetry and how it ultimately might influence cell fate.


2014 ◽  
Author(s):  
Patrick Seale ◽  
Wenshan Wang ◽  
Sona Rajakumari ◽  
Matthew Harms

Sign in / Sign up

Export Citation Format

Share Document