Nucleologenesis and Embryonic Genome Activation are Defective in Interspecies Cloned Embryos Between Bovine Ooplasm and Rhesus Monkey Somatic Cells

2011 ◽  
pp. 255-278
Keyword(s):  
Rhesus Monkey ◽  
Somatic Cells ◽  
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

scholarly journals Human embryonic genome activation initiates at the one-cell stage

2021 ◽  
Author(s):  
Maki Asami ◽  
Brian Y.H. Lam ◽  
Marcella K. Ma ◽  
Kara Rainbow ◽  
Stefanie Braun ◽  
...  
Keyword(s):  
Cell Stage ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
The One ◽  
Genome Activation

69 GLOBAL H3k9ac AND H3k27me3 EXPRESSION IN BLASTOMERES FROM 8- TO 16-CELL STAGE BOVINE EMBRYOS

2014 ◽  
Vol 26 (1) ◽  
pp. 148
Author(s):  
C. S. Oliveira ◽  
N. Z. Saraiva ◽  
L. Z. Oliveira ◽  
R. V. Serapião ◽  
M. R. de Lima ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Histone Modifications ◽  
Pearson Correlation ◽  
Developmental Competence ◽  
Bovine Embryos ◽  
Cell Stage ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
Group A ◽  
Genome Activation

Embryonic genome activation is a crucial step in early embryo development, and is accompanied by a dramatic change in the epigenetic profile of blastomeres. Histone modifications related to euchromatin and heterochromatin can be important parameters to infer developmental competence, as they are affected by manipulation and environmental stress conditions. The aim of this study was to characterise permissive (H3k9ac) and repressive (H3k27me3) histone modifications during the embryonic genome activation cell cycle in bovine embryos, regarding correlation between those marks and variance among blastomeres. For that, bovine embryos were produced by IVF and cultured in SOF medium supplemented with 5 mg mL–1 of BSA and 2.5% FCS in 5% O2 in an air atmosphere for 5 days (70 h after IVF). The 8 to 16 cell embryos were fixed in 4% paraformaldehyde and submitted to H3k9ac and H3k27me3 immunofluorescence assay (mouse anti-H3K9ac monoclonal antibody, 1 : 200; Sigma; rabbit anti-H3k27me3 monoclonal antibody, 1 : 200; Upstate, Charlottesville, VA, USA). Nuclei were counterstained with Hoechst 33342. Images of each embryo were captured (AxioCam, Carl Zeiss, São Paulo, Brazil) and measured for nuclear fluorescence intensity in each blastomere using Adobe Photoshop CS3 (Adobe Systems, San Jose, CA, USA). Mean levels were compared using the Mann-Whitney test and variances were compared using F-test (SAS 9.1, SAS Institute Inc., Cary, NC, USA; P = 0.05). We evaluated 2 replicates and 12 embryos during the transition from the 8 to 16 cell stages, totaling 169 blastomeres. Global H3k27me3 levels varied accordingly to H3k9ac levels, as indicated by a high Pearson correlation coefficient (r = 0.913). Levels of each blastomere were normalized to the lowest level obtained within each embryo. Some embryos displayed a high variation between blastomeres, and, for further analysis, we divided the embryos into groups: group A for embryos that presented similar H3k9ac levels between blastomeres (8 embryos, 66%), and group B for embryos that exhibited higher heterogeneity between blastomeres (at least 2 blastomeres presenting a 2-fold increase compared to the lowest blastomere; 4 embryos, 33%). Mean H3k9ac and H3k27me3 normalized levels were lower for group A [H3k9ac: 1.35 ± 0.29 (A), 1.94 ± 1.02* (B); H3k27me3: 1.33 ± 0.24 (A), 1.99 ± 0.77 (B)], and group A displayed lower variance values (H3k9ac: 0.07 (A), 1.05* (B); H3k27me3: 0.06 (A), 0.60 (B)]. Within each embryo, blastomeres were sorted in ascending order for H3k9ac level (1 to 16), and compared between groups A and B. We detected that mean levels differed (P < 0.05) between groups from blastomere 9 to 16 for H3k9ac and 10 to 16 for H3k27me3. Therefore, in 8- to 16-cell stage embryos, the H3k27me3 repressive mark is highly correlated with the H3k9ac permissive mark. Also, our results describe the presence of 2 distinguishable populations of bovine embryos at this stage, considering their epigenetic status. One population presented similar levels of repressive and permissive marks among blastomeres, whereas the second one displayed a remarkable variation among their blastomeres. This observation should be further studied, as it might reflect distinct cleavage pattern embryos and blastomere competence. The authors acknowledge FAPESP, FAPERJ and CNPq for financial support.

61 REVERSIBLE INHIBITION OF BOVINE MINOR EMBRYONIC GENOME ACTIVATION IMPAIRS PRE-IMPLANTATION DEVELOPMENT

2017 ◽  
Vol 29 (1) ◽  
pp. 138
Author(s):  
R. P. Nociti ◽  
R. V. Sampaio ◽  
V. F. M. H. de Lima ◽  
R. M. Schultz ◽  
P. J. Ross
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Reversible Inhibitor ◽  
Blastocyst Formation ◽  
Cell Stage ◽  
Developmental Potential ◽  
Embryonic Genome Activation ◽  
Transcriptional Inhibition ◽  
Embryonic Genome ◽  
Genome Activation

Bovine pre-implantation embryos can develop in the absence of gene expression up to the 8/16-cell stage, the time when the major embryonic genome activation (EGA) occurs. Some embryonic genes, however, are transcribed before EGA (minor EGA). This study used a reversible inhibitor of RNA Polymerase II (5,6 dichlorobenzimidazole 1-β-D-ribofuranoside; DRB) to assess the importance of minor EGA for development to the blastocyst stage. Oocytes were matured and inseminated in vitro, and the fertilized eggs were cultured in supplemented KSOMaa and allocated to different treatments 16 h post-insemination (hpi). Development was recorded at 44 and 72 hpi, and the incidence of blastocyst formation on Day 7 (IVF = Day 0) was recorded. Data were analysed by ANOVA followed by Duncan test. First, we tested different DRB concentrations [50 μM (D50), 75 μM (D75), 100 μM (D100), and dimethyl sulfoxide vehicle control (CTRL)] to block development to blastocyst when continuously present. Only embryos in CTRL produced blastocysts (45.0 ± 5.8%; 4 replicates with a total of 391 oocytes examined). No difference in development was observed at 44 h (57.9 ± 16.5, 53.3 ± 10.5, 60.5 ± 19.0, and 52.3 ± 5.8% for D50, D75, D100, and CTRL, respectively) and 72 h (78.9 ± 8.8, 66.1 ± 11.7, 71.5 ± 16.5, and 70.8 ± 5.6% for D50, D75, D100, and CTRL, respectively). Next, in 7 replicates (751 oocytes) we determined the effect of blocking transcription (50 μM DRB) spanning 2 embryo stages (periods of 28 h), initiated at 16 hpi (1&2C), 30 hpi (2&4C), and 44 hpi (4&8C). Controls included DRB treatment from 16 to 72 hpi (1–8C) and CTRL. There was no difference in development at 44 and 72 h. The incidence of blastocyst formation, however, was significantly decreased in all treatment groups compared with CTRL (27.7 ± 4.7; 15.1 ± 3.5; 23.3 ± 3.1; 20.5 ± 1.9; and 42.1 ± 3.2% for 1&2C, 2&4C, 4&8C, 1–8C, and CTRL, respectively). Finally, in 12 replicates (1499 oocytes), the effect of blocking transcription for 14-h periods, spanning mostly a unique cleavage stage, was evaluated. The DRB treatment (50 μM) started at 16 hpi (1C), 30 hpi (2C), 44 hpi (4C), and 58 hpi (8C). Furthermore, 1–16C and CTRL treatments were included. No difference in development at 44 and 72 h were observed. Development to the blastocyst was significantly lower from CTRL (46.0 ± 3.2%) in 2C, 4C, 8C, and 1–16C (28.9 ± 3.9, 26.1 ± 4.2, 30.1 ± 4.8, and 18.9 ± 3.2%, respectively) but not in 1C (34.7 ± 4.4%). In summary, continuous transcriptional inhibition using DRB resulted in a developmental block at the time of major EGA, similar to α-amanitin treatment (an irreversible RNA Polymerase II inhibitor). Transcriptional inhibition during single cleavage stages was sufficient to decrease the developmental potential of the embryo. We conclude that minor EGA has an important role for bovine development. This work was funded by NIH-NICHD R01HD070044 to P. J. Ross. R. P. Nociti was sponsored by CNPQ; R. V. Sampaio was sponsored by FAPESP.

The role of RNA-polymerase II transcription in embryonic nucleologenesis by bovine embryos

Biologia ◽  
2010 ◽  
Vol 65 (3) ◽  
Author(s):  
Mária Kovalská ◽  
Ida Petrovičová ◽  
František Strejček ◽  
Marian Adamkov ◽  
Erika Halašová ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
De Novo ◽  
Control Group ◽  
Bovine Embryos ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
Autoradiographic Labeling ◽  
Genome Activation

AbstractThe early stages of embryonic development are maternally driven. As development proceeds, maternally inherited informational molecules decay, and embryogenesis becomes dependent on de novo synthesized RNAs of embryonic genome. The aim of the present study is to investigate the role of de novo transcription in the development of embryos during embryonic genome activation. Autoradiography for detection of transcriptional activity and transmission electron microscopy were applied in in vitro produced bovine embryos cultured to the late 8-cell stage with or without (control group) α-amanitin, specific inhibitor of RNA-polymerases II and III transcription. The α-amanitin (AA) groups presented three sets of embryos cultivated with AA in different time intervals (6, 9 and 12 h). In control group, nucleoplasm and nucleolar structures displayed strong autoradiographic labeling and showed initial development of fibrillo-granular nucleoli. In α-amanitin groups, lack of autoradiographic labeling and disintegrated nucleolus precursor bodies (NPBs) stage were observed. Inhibition of RNA polymerase II (RNA pol II) already in the early phases of embryonic genome activation has detrimental effect on nucleolar formation and embryo survival, what was shown for the first time.

Non-invasive imaging of human embryos before embryonic genome activation predicts development to the blastocyst stage

2010 ◽  
Vol 28 (10) ◽  
pp. 1115-1121 ◽  
Author(s):  
Connie C Wong ◽  
Kevin E Loewke ◽  
Nancy L Bossert ◽  
Barry Behr ◽  
Christopher J De Jonge ◽  
...  
Keyword(s):  
Blastocyst Stage ◽  
Human Embryos ◽  
Embryonic Genome Activation ◽  
Non Invasive ◽  
Embryonic Genome ◽  
Genome Activation

Genetic variation in resistance of the preimplantation bovine embryo to heat shock

2015 ◽  
Vol 27 (1) ◽  
pp. 22 ◽  
Author(s):  
Peter J. Hansen
Keyword(s):  
Genetic Variation ◽  
Heat Stress ◽  
Elevated Temperature ◽  
Heat Shock ◽  
Body Temperature ◽  
Cellular Function ◽  
Genetic Differences ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
Genome Activation

Reproduction is among the physiological functions in mammals most susceptible to disruption by hyperthermia. Many of the effects of heat stress on function of the oocyte and embryo involve direct effects of elevated temperature (i.e. heat shock) on cellular function. Mammals limit the effects of heat shock by tightly regulating body temperature. This ability is genetically controlled: lines of domestic animals have been developed with superior ability to regulate body temperature during heat stress. Through experimentation in cattle, it is also evident that there is genetic variation in the resistance of cells to the deleterious effects of elevated temperature. Several breeds that were developed in hot climates, including Bos indicus (Brahman, Gir, Nelore and Sahiwal) and Bos taurus (Romosinuano and Senepol) are more resistant to the effects of elevated temperature on cellular function than breeds that evolved in cooler climates (Angus, Holstein and Jersey). Genetic differences are expressed in the preimplantation embryo by Day 4–5 of development (after embryonic genome activation). It is not clear whether genetic differences are expressed in cells in which transcription is repressed (oocytes >100 µm in diameter or embryos at stages before embryonic genome activation). The molecular basis for cellular thermotolerance has also not been established, although there is some suggestion for involvement of heat shock protein 90 and the insulin-like growth factor 1 system. Given the availability of genomic tools for genetic selection, identification of genes controlling cellular resistance to elevated temperature could be followed by progress in selection for those genes within the populations in which they exist. It could also be possible to introduce genes from thermotolerant breeds into thermally sensitive breeds. The ability to edit the genome makes it possible to design new genes that confer protection of cells from stresses like heat shock.

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