scholarly journals Causes of developmental failure of in-vitro matured rhesus monkey oocytes: impairments in embryonic genome activation

2003 ◽  
Vol 18 (4) ◽  
pp. 826-833 ◽  
Author(s):  
R.D. Schramm
Keyword(s):  
Rhesus Monkey ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
Genome Activation

Impairments in Embryonic Genome Activation in Rhesus Monkey Somatic Cell Nuclear Transfer Embryos

2008 ◽  
Vol 10 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Yuyu Niu ◽  
Shihua Yang ◽  
Yang Yu ◽  
Chenhui Ding ◽  
Jifeng Yang ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
Genome Activation

The stage of embryonic genome activation in bovine embryos following in vitro fertilization

1999 ◽  
Vol 51 (1) ◽  
pp. 188 ◽  
Author(s):  
E-H Park ◽  
R-C Chian ◽  
H-M Chung ◽  
J-G Lim ◽  
J-J Ko ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Bovine Embryos ◽  
Vitro Fertilization ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
Genome Activation

scholarly journals 119 THE LOCALIZATION OF A METHYL BINDING DOMAIN PROTEIN (MBD4) IN MURINE AND BOVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS

2005 ◽  
Vol 17 (2) ◽  
pp. 210
Author(s):  
N. Ruddock ◽  
J. Xue ◽  
L. Sanchez-Partida ◽  
M. Cooney ◽  
N. Korfiatis ◽  
...  
Keyword(s):  
Binding Domain ◽  
Primary Antibody ◽  
Epifluorescence Microscopy ◽  
Cell Stage ◽  
Embryonic Genome Activation ◽  
Stage Of Development ◽  
Embryonic Genome ◽  
Genome Activation ◽  
Bovine Oocytes

The presence of MBD4, a member of the methyl binding domain family, was investigated in both murine and bovine oocytes and pre-implantation embryos. MBD4 is the only MBD family member that is involved in DNA repair but not active in transcriptional repression or in the formation of complexes with histone deacetylase complexes (HDACs). It contains a mismatch-specific glycosylase domain that acts to repair G:T mismatches within a CpG context. Bovine cumulus oocyte complexes were collected from abattoir-derived ovaries, matured in vitro and used for IVF as described previously (Ruddock et al. 2004 Biol. Reprod. 70, 1131–1135). Samples were analyzed at all steps in this process. Murine oocytes were collected from superovulated mice (C57BL6 × CBA) and subjected to conventional IVF. A polyclonal antibody derived in the rabbit against human peptides from specific regions of MBD4 (Imgenex, San Diego, CA, USA) was used to localize MBD4 protein. This antibody was tested at a variety of concentrations against both human HL60 leukemia cells and bovine embryos. Staining of HL60 cells was optimum at 32–64 μg/mL and embryos at 64 μg/mL. Briefly, the staining protocol consisted of fixing cells and zona-free oocytes or embryos in 4% paraformaldehyde for 15 min, followed by 15 min in 0.1% Triton X-100. Primary antibody incubation was performed overnight at 4°C. Embryos were then washed in blocking buffer for 1 hr prior to incubation at 4°C in mouse anti-rabbit IgG conjugated to FITC in blocking buffer for 30 min in the dark. Lastly, embryos were incubated in 10 μg/L Hoescht 33342 for 15 min, and then washed and mounted with Vectashield (Vector Labs, Burlingame, CA, USA). Negative controls contained no primary antibody. Mounted cells/embryos were viewed by epifluorescence microscopy. MBD4 was found to be expressed in both murine and bovine oocytes and pre-implantation embryos. In the cow, faint nuclear expression was detected at the 2-cell stage, followed by exclusion of the protein from the nucleus until the blastocyst stage of development. At this stage, staining was primarily nuclear and quite intense. In the mouse, staining was cytoplasmic at the 2 pronuclear stage, but was then concentrated in the nucleus from the 2-cell stage onward. It will be interesting to determine if this is due to the different timing of embryonic genome activation between the two species, hence implying a role for MBD4 in this important biological process. Further investigations are underway to compare the subcellular localization of the other MBD proteins in both species during preimplantation development and to identify a role for MBD4 in embryonic genome activation.

scholarly journals Modelling human zygotic genome activation in 8C-like cells in vitro

2021 ◽  
Author(s):  
Jasmin Taubenschmid-Stowers ◽  
Maria Rostovskaya ◽  
Fatima Santos ◽  
Sebastian Ljung ◽  
Ricard Argelaguet ◽  
...  
Keyword(s):  
Embryonic Stem ◽  
Human Embryos ◽  
Marker Genes ◽  
Cell Stage ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
Cell Embryo ◽  
Genome Activation

The remodelling of the epigenome and transcriptome of the fertilised oocyte to establish totipotency in the zygote and developing embryo is one of the most critical processes in mammalian embryogenesis. Zygotic or embryonic genome activation (ZGA, EGA) in the 2-cell embryo in mouse, and the 8-cell embryo in humans, constitutes the first major wave of transcription. Failure to initiate ZGA leads to developmental defects, and contributes to the high attrition rates of human pre-implantation embryos. Due to limitations in cell numbers and experimental tractability, the mechanisms that regulate human embryonic genome activation in the totipotent embryo remain poorly understood. Here we report the discovery of human 8-cell like cells (8CLCs) specifically among naive embryonic stem cells, but not primed pluripotent cells. 8CLCs express ZGA marker genes such as ZSCAN4, LEUTX and DUXA and their transcriptome closely resembles that of the 8-cell human embryo. 8-cell like cells reactivate 8-cell stage specific transposable elements such as HERVL and MLT2A1 and are characterized by upregulation of the DNA methylation regulator DPPA3. 8CLCs show reduced SOX2 protein, and can be identified based on expression of the novel ZGA-associated protein markers TPRX1 and H3.Y in vitro. Overexpression of the transcription factor DUX4 as well as spliceosome inhibition increase ZGA-like transcription and enhance TPRX1+ 8CLCs formation. Excitingly, the in vitro identified 8CLC marker proteins TPRX1 and H3.Y are also expressed in 8-cell human embryos at the time of genome activation and may thus be relevant in vivo. The discovery of 8CLCs provides a unique opportunity to model and manipulate human ZGA-like transcriptional programs in vitro, and might provide critical functional insights into one of the earliest events in human embryogenesis in vivo.

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