scholarly journals Retinoic acid signaling is critical during the totipotency window in early mammalian development

Author(s):  
Ane Iturbide ◽  
Mayra L. Ruiz Tejeda Segura ◽  
Camille Noll ◽  
Kenji Schorpp ◽  
Ina Rothenaigner ◽  
...  

AbstractTotipotent cells hold enormous potential for regenerative medicine. Thus, the development of cellular models recapitulating totipotent-like features is of paramount importance. Cells resembling the totipotent cells of early embryos arise spontaneously in mouse embryonic stem (ES) cell cultures. Such ‘2-cell-like-cells’ (2CLCs) recapitulate 2-cell-stage features and display expanded cell potential. Here, we used 2CLCs to perform a small-molecule screen to identify new pathways regulating the 2-cell-stage program. We identified retinoids as robust inducers of 2CLCs and the retinoic acid (RA)-signaling pathway as a key component of the regulatory circuitry of totipotent cells in embryos. Using single-cell RNA-seq, we reveal the transcriptional dynamics of 2CLC reprogramming and show that ES cells undergo distinct cellular trajectories in response to RA. Importantly, endogenous RA activity in early embryos is essential for zygotic genome activation and developmental progression. Overall, our data shed light on the gene regulatory networks controlling cellular plasticity and the totipotency program.

2021 ◽  
Author(s):  
Masahito Yoshihara ◽  
Ida Kirjanov ◽  
Sonja Nykänen ◽  
Joonas Sokka ◽  
Jere Weltner ◽  
...  

AbstractDUX4 has recently been recognized as a key regulator in human embryonic genome activation (EGA). The exact role of DUX4 in human embryo is still elusive, partly due to the cytotoxicity of persistent DUX4 expression in cellular models. We report here that a transient DUX4 expression in human embryonic stem cells (hESCs) retains cell viability while inducing an EGA-like expression program in a subpopulation of the cells. These cells showed resemblance to 8-cell stage blastomeres and were thus named induced blastomere-like (iBM) cells. Trajectory inference from the single-cell RNA-seq data suggested that the expression profile of these cells progressed in a manner similar to the morula to blastocyst transition in human embryo. Finally, viable iBM cells could be enriched using an antibody against NaPi2b (SLC34A2), paving the way for further experimental approaches. The iBM cells can become a powerful tool to model transcriptional dynamics and regulation during early human embryogenesis.


Genetics ◽  
2002 ◽  
Vol 160 (2) ◽  
pp. 675-682
Author(s):  
Victoria L Browning ◽  
Rebecca A Bergstrom ◽  
Sandra Daigle ◽  
John C Schimenti

Abstract Proper levels of gene expression are important for normal mammalian development. Typically, altered gene dosage caused by karyotypic abnormalities results in embryonic lethality or birth defects. Segmental aneuploidy can be compatible with life but often results in contiguous gene syndromes. The ability to manipulate the mouse genome allows the systematic exploration of regions that are affected by alterations in gene dosage. To explore the effects of segmental haploidy in the mouse t complex on chromosome 17, radiation-induced deletion complexes centered at the Sod2 and D17Leh94 loci were generated in embryonic stem (ES) cells. A small interval was identified that, when hemizygous, caused specific embryonic lethal phenotypes (exencephaly and edema) in most fetuses. The penetrance of these phenotypes was background dependent. Additionally, evidence for parent-of-origin effects was observed. This genetic approach should be useful for identifying genes that are imprinted or whose dosage is critical for normal embryonic development.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhi-Qiang Du ◽  
Hao Liang ◽  
Xiao-Man Liu ◽  
Yun-Hua Liu ◽  
Chonglong Wang ◽  
...  

AbstractSuccessful early embryo development requires the correct reprogramming and configuration of gene networks by the timely and faithful execution of zygotic genome activation (ZGA). However, the regulatory principle of molecular elements and circuits fundamental to embryo development remains largely obscure. Here, we profiled the transcriptomes of single zygotes and blastomeres, obtained from in vitro fertilized (IVF) or parthenogenetically activated (PA) porcine early embryos (1- to 8-cell), focusing on the gene expression dynamics and regulatory networks associated with maternal-to-zygote transition (MZT) (mainly maternal RNA clearance and ZGA). We found that minor and major ZGAs occur at 1-cell and 4-cell stages for both IVF and PA embryos, respectively. Maternal RNAs gradually decay from 1- to 8-cell embryos. Top abundantly expressed genes (CDV3, PCNA, CDR1, YWHAE, DNMT1, IGF2BP3, ARMC1, BTG4, UHRF2 and gametocyte-specific factor 1-like) in both IVF and PA early embryos identified are of vital roles for embryo development. Differentially expressed genes within IVF groups are different from that within PA groups, indicating bi-parental and maternal-only embryos have specific sets of mRNAs distinctly decayed and activated. Pathways enriched from DEGs showed that RNA associated pathways (RNA binding, processing, transport and degradation) could be important. Moreover, mitochondrial RNAs are found to be actively transcribed, showing dynamic expression patterns, and for DNA/H3K4 methylation and transcription factors as well. Taken together, our findings provide an important resource to investigate further the epigenetic and genome regulation of MZT events in early embryos of pigs.


2005 ◽  
Vol 280 (16) ◽  
pp. 16484-16498 ◽  
Author(s):  
Eduardo Martinez-Ceballos ◽  
Pierre Chambon ◽  
Lorraine J. Gudas

Homeobox (Hox) genes encode a family of transcription factors that regulate embryonic patterning and organogenesis. In embryos, alterations of the normal pattern of Hox gene expression result in homeotic transformations and malformations. Disruption of theHoxa1gene, the most 3′ member of the Hoxa cluster and a retinoic acid (RA) direct target gene, results in abnormal ossification of the skull, hindbrain, and inner ear deficiencies, and neonatal death. We have generated Hoxa1-/-embryonic stem (ES) cells (named Hoxa1-15) from Hoxa1-/-mutant blastocysts to study the Hoxa1 signaling pathway. We have characterized in detail these Hoxa1-/-ES cells by performing microarray analyses, and by this technique we have identified a number of putative Hoxa-1 target genes, including genes involved in bone development (e.g. Col1a1,Postn/Osf2, and the bone sialoprotein gene orBSP), genes that are expressed in the developing brain (e.g. Nnat,Wnt3a,BDNF,RhoB, andGbx2), and genes involved in various cellular processes (e.g. M-RAS,Sox17,Cdkn2b,LamA1,Col4a1,Foxa2,Foxq1,Klf5, andIgf2). Cell proliferation assays and Northern blot analyses of a number of ES cell markers (e.g. Rex1,Oct3/4,Fgf4, andBmp4) suggest that the Hoxa1 protein plays a role in the inhibition of cell proliferation by RA in ES cells. Additionally, Hoxa1-/-ES cells express high levels of various endodermal markers, includingGata4andDab2, and express much lessFgf5after leukemia inhibitory factor (LIF) withdrawal. Finally, we propose a model in which the Hoxa1 protein mediates repression of endodermal differentiation while promoting expression of ectodermal and mesodermal characteristics.


2014 ◽  
Vol 369 (1657) ◽  
pp. 20130542 ◽  
Author(s):  
David-Emlyn Parfitt ◽  
Michael M. Shen

To date, many regulatory genes and signalling events coordinating mammalian development from blastocyst to gastrulation stages have been identified by mutational analyses and reverse-genetic approaches, typically on a gene-by-gene basis. More recent studies have applied bioinformatic approaches to generate regulatory network models of gene interactions on a genome-wide scale. Such models have provided insights into the gene networks regulating pluripotency in embryonic and epiblast stem cells, as well as cell-lineage determination in vivo . Here, we review how regulatory networks constructed for different stem cell types relate to corresponding networks in vivo and provide insights into understanding the molecular regulation of the blastocyst–gastrula transition.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Stefanie Schmitteckert ◽  
Cornelia Ziegler ◽  
Liane Kartes ◽  
Alexandra Rolletschek

Transcription factor Lbx1 is known to play a role in the migration of muscle progenitor cells in limb buds and also in neuronal determination processes. In addition, involvement of Lbx1 in cardiac neural crest-related cardiogenesis was postulated. Here, we used mouse embryonic stem (ES) cells which have the capacity to develop into cells of all three primary germ layers. Duringin vitrodifferentiation, ES cells recapitulate cellular developmental processes and gene expression patterns of early embryogenesis. Transcript analysis revealed a significant upregulation ofLbx1at the progenitor cell stage. Immunofluorescence staining confirmed the expression of Lbx1 in skeletal muscle cell progenitors and GABAergic neurons. To verify the presence of Lbx1 in cardiac cells, triple immunocytochemistry of ES cell-derived cardiomyocytes and a quantification assay were performed at different developmental stages. Colabeling of Lbx1 and cardiac specific markers troponin T, α-actinin, GATA4, and Nkx2.5 suggested a potential role in early myocardial development.


Author(s):  
Virginia Papaioannou ◽  
Randall Johnson

The ability of mammalian embryos to incorporate foreign cells and develop as chimeras has been exploited for a variety of purposes including the elucidation of cell lineages, the investigation of cell potential, the perpetuation of mutations produced in embryonic stem (ES) cells by gene targeting, and the subsequent analysis of these mutations. The extent of contribution of the foreign cells depends on their developmental synchrony with the host embryo and their mitotic and developmental potential, which may be severely restricted if the cells bear mutations. If the goal in making chimeras is the transmission of a mutation produced by gene targeting to the next generation, the mutant ES cells must have the capacity to undergo meiosis and gametogenesis. Cells from two different mammalian embryos were first combined experimentally to produce a composite animal, dubbed a chimera, nearly four decades ago. Pairs of cleaving, pre-implantation embryos were mechanically associated in vitro until they aggregated together to make single large morulae; these in turn resulted in chimeric offspring (1). Genetic markers were used to distinguish the contributions of the two embryos in these animals. Since then, various methods for making chimeras have been explored to address different types of questions (2). In 1972 it was reported that highly asynchronous embryonic cells, which had been cultured in vitro, could contribute to chimeras upon re-introduction into pre-implantation embryos (3). Not long afterward, several groups working with teratocarcinomas, tumours derived from germ cells of the gonad, discovered that stem cells from these tumours, known as embryonal carcinoma cells, could contribute to an embryo if introduced into pre-implantation stages (4-6). It appeared that the undifferentiated stem cells of the tumour had enough features in common with early embryonic cells that they could respond to the embryonic environment, differentiating in a normal manner, even after long periods in vitro. Their embryonic potential was limited, however, and many teratocarcinoma cell lines made only meagre contributions to the developing fetus or even produced tumours in chimeras (7). Either their derivation from tumours or their extended sojourn in vitro rendered these cells so dissimilar from early embryonic cells that they rarely, if ever, had full embryonic potential.


2006 ◽  
Vol 18 (2) ◽  
pp. 248
Author(s):  
S.-G. Lee ◽  
C.-H. Park ◽  
D.-H. Choi ◽  
H.-Y. Son ◽  
C.-K. Lee

Use of blastocysts produced in vitro would be an efficient way to generate embryonic stem (ES) cells for the production of transgenic animals and the study of developmental gene regulation. In pigs, the morphology and cell number of in vitro-produced blastocysts are inferior to these parameters in their in vivo counterparts. Therefore, establishment of ES cells from blastocysts produced in vitro might be hindered by poor embryo quality. The objective of this study was to increase the cell number of blastocysts derived by aggregating 4–8-cell stage porcine embryos produced in vitro. Cumulus–oocyte complexes were collected from prepubertal gilt ovaries, and matured in vitro. Embryos at the 4–8-cell stage were produced by culturing embryos for two days after in vitro fertilization (IVF). After removal of the zona pellucida with acid Tyrode’s solution, one (1X), two (2X), and three (3X) 4–8-cell stage embryos were aggregated by co-culturing them in aggregation plates followed by culturing to the blastocyst stage. After 7 days, the developmental ability and the number of cells in aggregated embryos were determined by staining with Hoechst 33342 and propidium iodide. The percentage of blastocysts was higher in both 2X and 3X aggregated embryos compared to that of 1X and that of intact controls (Table 1). The cell number of blastocysts also increased in aggregated embryos compared to that of non-aggregated (1X) embryos and controls. This result suggests that aggregation might improve the quality of in vitro-fertilized porcine blastocysts by increasing cell numbers, thus becoming a useful resource for isolation and establishment of porcine ES cells. Further studies are required to investigate the quality of the aggregated embryos in terms of increasing the pluripotent cell population by staining for Oct-4 and to apply improved aggregation methods in nuclear-transferred (NT) porcine embryos. Table 1. Development, cell number, and ICM ratio of aggregated porcine embryos


2008 ◽  
Vol 20 (1) ◽  
pp. 224
Author(s):  
J. Okahara-Narita ◽  
J. Yamasaki ◽  
C. Iwatani ◽  
H. Tsuchiya ◽  
K. Wakimoto ◽  
...  

The establishment of most embryonic stem (ES) cell lines requires the destruction of embryos. Some ES cell lines in mice and humans are currently derived from a single blastomere, so that remaining blastomeres can still develop into fetuses. However, the procedures currently in use for establishing these lines are very complicated, and other ES cell lines from the same species are needed (Chung et al. 2006 Nature 439, 216–219; Klimanskaya et al. 2006 Nature 444, 481–485). The objective of this study was to devise a method simpler than those previously described for establishing ES cell lines from a single blastomere in the cynomolgus monkey. Controlled ovarian stimulation and oocyte recovery have been described previously by Torii et al. (2000 Primates 41, 39–47). Cumulus-free mature oocytes were fertilized by intracytoplasmic sperm injection (ICSI), and then cultured at 38�C in 5% CO2, 5% O2 for 2 days. The zona pellucida of 4- to 5-cell-stage embryos was disrupted using acidic Tyrode's solution, and individual blastomeres were separated from the denuded embryos using trypsin. These blastomeres were cultured on mitomycin-C-treated mouse embryonic fibroblasts and ES medium containing adrenocorticotropic hormone (ACTH) (Ogawa et al. 2004 Genes to Cells 9, 471–477). After the formation of initial outgrowths, half of the medium was changed every other day until the outgrowths reached approximately 100 cells. Passage of putative monkey ES cells was performed by mechanical dispersion of the colonies and transfer to fresh feeders every 3–4 days until there were enough cells for enzymatic dispersion. One stable ES cell line was obtained from two 4- or 5-cell-stage embryos using ES medium containing ACTH. The morphology of this ES cell colony was consistent with the monkey ES cell colony previous described by Suemori et al. (2001 Dev. Dynamics 222, 273–279). The ES cell line was passaged more than 17 times, and the morphology of the ES cell colony did not differ between the first and seventeenth passages. The ES cells showed normal karyotype and retained pluripotency markers for primate ES cells including octamer-binding protein 4 (Oct-4), stage-specific embryonic antigen (SSEA)-4, tumor-rejection antigen (TRA)-1-60, and TRA-1-81. We are presently confirming whether this ES cell line possesses potencies to differentiate in all three embryonic germ layers using both an in vitro assay and teratoma formation. Here we showed that cynomolgus monkey ES cells can be derived from a single blastomere, without co-culturing another ES cell line, as has been done in previous studies on mice and humans. This method allows the establishment of ES cell lines from a single blastomere, leaving the other blastomeres available for embryo transfer. Thus, the method described here is simpler than previously described methods and alleviates some ethical concerns.


2014 ◽  
Vol 35 (5) ◽  
pp. 770-777 ◽  
Author(s):  
Sharon Schlesinger ◽  
Stephen P. Goff

Retroviruses have evolved complex transcriptional enhancers and promoters that allow their replication in a wide range of tissue and cell types. Embryonic stem (ES) cells, however, characteristically suppress transcription of proviruses formed after infection by exogenous retroviruses and also of most members of the vast array of endogenous retroviruses in the genome. These cells have unusual profiles of transcribed genes and are poised to make rapid changes in those profiles upon induction of differentiation. Many of the transcription factors in ES cells control both host and retroviral genes coordinately, such that retroviral expression patterns can serve as markers of ES cell pluripotency. This overlap is not coincidental; retrovirus-derived regulatory sequences are often used to control cellular genes important for pluripotency. These sequences specify the temporal control and perhaps “noisy” control of cellular genes that direct proper cell gene expression in primitive cells and their differentiating progeny. The evidence suggests that the viral elements have been domesticated for host needs, reflecting the wide-ranging exploitation of any and all available DNA sequences in assembling regulatory networks.


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