15 Identification of developmental genes regulated by H3K9me2 and H3K27me3 histone marks in bovine somatic cells and their somatic cell nuclear transfer embryos

2022 ◽  
Vol 34 (2) ◽  
pp. 241
Author(s):  
I. Viotti Perisse ◽  
B. Abercrombie ◽  
Y. Liu ◽  
T. Patrick ◽  
J. Keim ◽  
...  
2005 ◽  
Vol 16 (8) ◽  
pp. 3887-3895 ◽  
Author(s):  
Matthias Becker ◽  
Antje Becker ◽  
Faiçal Miyara ◽  
Zhiming Han ◽  
Maki Kihara ◽  
...  

The embryonic genome is formed by fusion of a maternal and a paternal genome. To accommodate the resulting diploid genome in the fertilized oocyte dramatic global genome reorganizations must occur. The higher order structure of chromatin in vivo is critically dependent on architectural chromatin proteins, with the family of linker histone proteins among the most critical structural determinants. Although somatic cells contain numerous linker histone variants, only one, H1FOO, is present in mouse oocytes. Upon fertilization H1FOO rapidly populates the introduced paternal genome and replaces sperm-specific histone-like proteins. The same dynamic replacement occurs upon introduction of a nucleus during somatic cell nuclear transfer. To understand the molecular basis of this dynamic histone replacement process, we compared the localization and binding dynamics of somatic H1 and oocyte-specific H1FOO and identified the molecular determinants of binding to either oocyte or somatic chromatin in living cells. We find that although both histones associate readily with chromatin in nuclei of somatic cells, only H1FOO is capable of correct chromatin association in the germinal vesicle stage oocyte nuclei. This specificity is generated by the N-terminal and globular domains of H1FOO. Measurement of in vivo binding properties of the H1 variants suggest that H1FOO binds chromatin more tightly than somatic linker histones. We provide evidence that both the binding properties of linker histones as well as additional, active processes contribute to the replacement of somatic histones with H1FOO during nuclear transfer. These results provide the first mechanistic insights into the crucial step of linker histone replacement as it occurs during fertilization and somatic cell nuclear transfer.


2015 ◽  
Vol 27 (1) ◽  
pp. 104
Author(s):  
N. L. Selokar ◽  
M. Saini ◽  
H. Agrawal ◽  
P. Palta ◽  
M. S. Chauhan ◽  
...  

Cryopreservation of semen allows preservation of somatic cells, which can be used for the production of progeny through somatic cell nuclear transfer (SCNT). This approach could enable restoration of valuable high-genetic-merit progeny-tested bulls, which may be dead but the cryopreserved semen is available. We have successfully produced a live buffalo calf by SCNT using somatic cells isolated from >10 year old frozen semen (Selokar et al. 2014 PLoS One 9, e90755). However, the calf survived only for 12 h, which indicates faulty reprogramming of these cells. The present study was, therefore, carried out to study the effect of treatment with trichostatin A (TSA), an epigenetic modifier, on reprogramming of these cells. Production of cloned embryos and determination of quality and level of epigenetic markers in blastocysts were performed according to the methods described previously (Selokar et al. 2014 PLoS One 9, e90755). To examine the effects of TSA (0, 50, and 75 nM), 10 separate experiments were performed on 125, 175, and 207 reconstructed embryos, respectively. The percentage data were analysed using SYSTAT 12.0 (SPSS Inc., Chicago, IL, USA) after arcsine transformation. Differences between means were analysed by one-way ANOVA followed by Fisher's least significant difference test for significance at P < 0.05. When the reconstructed buffalo embryos produced by hand-made clones were treated with 0, 50, or 75 nM TSA post-electrofusion for 10 h, the cleavage percentage (100.0 ± 0, 94.5 ± 2.3, and 96.1 ± 1.2, respectively) and blastocyst percentage (50.6 ± 2.3, 48.4 ± 2.7, and 48.1 ± 2.6, respectively), total cell number (274.9 ± 17.4, 289.1 ± 30.1, and 317.0 ± 24.2, respectively), and apoptotic index (3.4 ± 0.9, 4.5 ± 1.4, and 5.6 ± 0.7, respectively) in Day 8 blastocysts were not significantly different among different groups. The TSA treatment increased (P < 0.05) the global level of H4K5ac but not that of H3K18a in embryos treated with 50 or 75 nM TSA compared with that in controls. In contrast, the level of H3K27me3 was significantly lower (P < 0.05) in cloned embryos treated with 75 nM TSA than in embryos treated with 50 nM TSA or controls. The ultimate test of the reprogramming potential of any donor cell type is its ability to produce live offspring. To examine the in vivo developmental potential of the 0, 50, or 75 nM TSA treated embryos, we transferred Day 8 blastocysts, 2 each to 5, 6, and 5 recipients, respectively, which resulted in 2 pregnancies from 75 nM TSA treated embryos. However, one pregnancy was aborted in the first trimester and the other in the third trimester. In conclusion, TSA treatment of reconstructed embryos produced from semen-derived somatic cells alters their epigenetic status but does not improve the live birth rate. We are currently optimizing an effective strategy to improve the cloning efficiency of semen-derived somatic cells.


2008 ◽  
Vol 20 (1) ◽  
pp. 102
Author(s):  
J. Liu ◽  
M. E. Westhusin ◽  
D. C. Kraemer

Somatic cells in semen could be a valuable source of nuclei for cloning animals by somatic cell nuclear transfer, especially when other ways of obtaining somatic cells are not available. The usefulness of the cells cultured from bovine semen for nuclear transfer was evaluated in the present study. Twelve ejaculates were collected from nine bulls representing three breeds: Charolais, Brahman, and a crossbreed rodeo bull. All of the samples were processed immediately, and somatic cells were isolated by centrifuging through 20%, 50%, and 90% percoll columns (Nel-Themaat et al. 2005 Reprod. Fertil. Dev. 17, 314–315). Somatic cell lines were obtained from 7 of the 12 ejaculates. These cell lines have classic epithelial morphology, express cytokeratin and vimentin, and proliferate well in the medium we previously designed for the epithelial cells in ovine semen (Jie Liu et al. 2007 Biol. Reprod. special issue, 177–178). Cell lines from three bulls that had been cultured in vitro for 1–2 months were used in the cloning experiments. Bovine ovaries were collected from a local slaughterhouse and transported to the laboratory in warm saline solution within 2–4 h. Compact cumulus–oocyte complexes with evenly distributed cytoplasm were selected and matured for 18 h at 38.5�C with 5% CO2 in humidified air. Cumulus cells were removed by pipetting in 0.3% hyaluronidase solution (Sigma Chemical Co., St. Louis, MO, USA) for 5 min. Oocytes were selected for the presence of a first polar body and stained in 5 µg mL–1 Hoechst 33342 (Sigma) and 5 µg mL–1 cytochalasin B (Sigma) for 10–15 min before enucleation. Successful enucleation was confirmed by brief exposure of the oocytes to ultraviolet light. Epithelial cell lines cultured to 90–100% confluence were trypsinized, and a single cell was inserted into the perivitelline space of an oocyte. Fusion was induced by applying two 1.8–1.9 kV cm–1, 20 µs direct-current pulses delivered by an Eppendorf Multiporator (Eppendorf, North America) in fusion medium comprising 0.28 m Mannitol (Sigma), 0.1 mm CaCl2 (Sigma), and 0.1 mm MgSO4 (Sigma). One and half to 2 h post fusion, activation was induced by applying two 0.3 kV cm–1, 55 µs direct-current pulses in the fusion medium, followed by incubation in 10 µg mL–1 cycloheximide (Sigma) and 5 µg mL–1 cytochalasin B for 5 h in a humidified 5% CO2, 5% O2, and 90% N2 gas mixture at 38.5�C. The embryos were washed three times and cultured in commercially available G1/G2 medium (Vitrolife, Inc., Englewood, CO, USA) for up to 10 days. Blastocyst development rates using somatic cells from three of the bulls, 1-year-old Charolais, 6-year-old Brahman, and 8-year-old Brahman, were 15.9% (18/113), 34.5% (29/84), and 14.4% (13/90) of the fused one-cell embryos, respectively. Of these blastocyst stage embryos, 38.9% (7/18), 72.4% (21/29), and 61.5% (8/13) hatched, respectively. The present study shows that epithelial cells cultured from bovine semen can be used to produce blastocyst-stage embryos by somatic cell nuclear transfer.


2017 ◽  
Vol 29 (1) ◽  
pp. 122
Author(s):  
B. R. Mordhorst ◽  
S. N. Bogue ◽  
K. D. Wells ◽  
J. A. Green ◽  
R. S. Prather

Somatic cells commonly used in nuclear transfer primarily utilise the tricarboxylic acid cycle and cellular respiration for energy production. Comparatively, the metabolism of somatic cells contrasts that of cells within early embryos, which predominantly use glycolysis and exhibit Warburg Effect (WE)-like characteristics. We hypothesised that fibroblast cells can become more blastomere-like if driven either pharmacologically or by oxygen constraint and could result in improved in vitro embryonic development after somatic cell nuclear transfer (SCNT). The pharmaceuticals used (PS48 and CPI-613) should decrease mitochondrial use of the tricarboxylic acid (TCA) cycle and promote the PI3K pathway, respectively. Furthermore, we hypothesised that oxygen constraint (1.3%) would hinder TCA cycle activity and promote glycolysis. The goal was to achieve a WE-like effect in donor cells before nuclear transfer (NT) by treating Day 35 porcine fetal fibroblasts with CPI-613 (100 µM), PS48 (10 µM), both drugs combined (MIX), or as controls (CON, 0 µM) for 7 days under stepwise oxygen constraint (OC; 1.3%) or under normal conditions (ON; 5%). Three biological replicates were collected and data were analysed for main effect of treatment via GLM procedure of SAS 9.4 (SAS Institute Inc., Cary, NC, USA). To determine if our treatments affected mitochondria respiratory capacity (thereby TCA cycle capability) within embryos, we measured mitochondrial membrane potential (Δψm) using JC-10, a biphasic cationic dye. Mitotracker green (MTG) was used to estimate mitochondrial quantity. The percentage of cells with low Δψm was increased (P = 0.02) with any CPI or MIX treatment (treatments ≥ 95%) compared with OC-PS48 and both control (ON and OC) treatments (treatments ≥ 77.4%), whereas ON-PS48 had an intermediate level (90.4%; error = 4.9%). Contrary to our prediction, MTG intensity was lower across all ON treatments compared with OC treatments (NO treatments ≤ 736 AU v. OC treatments ≥ 872 AU; error = 23 AU; P < 0.01). Regardless of oxygen level, controls and PS48 treatments yielded the highest percentages of viable cells (treatments ≥ 94%) and OC-CPI and NO-MIX the lowest (treatments ≤ 86%) with NO-CPI and OC-MIX being intermediate (treatments ≥ 90%; error = 3%; P < 0.01). Oxygen constraint did not promote a reduction in mitochondrial membrane potential in pharmacologically treated fibroblasts. Additionally, intensity of MTG was increased in fibroblasts cultured under oxygen constraint compared with those cultured in 5% oxygen. Our results warrant further investigation of the mitochondrial changes occurring with oxygen deprivation in donor-cells. Experiments are underway to determine if gene expression in cells treated pharmacologically and with oxygen constraint are augmented, and whether these treatments will result in better development after SCNT. This study was funded by Food for the 21 st Century and NIH R01HD080636.


2009 ◽  
Vol 21 (1) ◽  
pp. 198
Author(s):  
T. Xiang ◽  
S. Walker ◽  
K. Gregg ◽  
W. Zhou ◽  
V. Farrar ◽  
...  

Oct-4, a POU domain-containing transcription factor encoded by Pou5f1, is selectively expressed in pre-implantation embryos and pluripotent stem cells, but not in somatic cells. Because of such a unique expression feature, Oct-4 can serve as a useful reprogramming indicator in somatic cell nuclear transfer (SCNT). Compared with data of Oct-4 expression in mouse and bovine cloned embryos, little is known about this gene in equine nuclear transfer. In the present study, we investigated Oct-4 expression in donor cells, oocytes, and SCNT embryos to evaluate reprogramming of equine somatic cells following nuclear transfer. Horse ovaries were obtained from a local slaughterhouse and the oocytes collected from the ovaries were matured in vitro in an M199-based medium (Galli et al. 2003 Nature 424, 635) for 24 h. Donor cells were derived from biopsy tissue samples of adult horses and cultured for 1 to 5 passages. Standard nuclear transfer procedures (Zhou et al. 2008 Mol. Reprod. Dev. 75, 744–758) were performed to produce cloned embryos derived from equine adult somatic cells. Cloned blastocysts were obtained after 7 days of in vitro culture of reconstructed embryos. Total RNA were extracted using Absolutely RNA Miniprep/Nanoprep kits (Stratagen, La Jolla, CA) from oocytes (n = 200), donor cells, and embryos (n = 5). DNase I treatment was included in the procedure to prevent DNA contamination. Semiquantitative RT-PCR was performed with optimized cycling parameters to analyze Oct-4, GDF9, and β-actin in equine donor cells, oocytes, and cloned blastocysts. The RT-PCR products were sequenced to verify identity of the genes tested. The relative expression abundance was calculated by normalizing the band intensity of Oct-4 to that of β-actin in each analysis. No transcript of Oct-4 was detected in equine somatic cells used as donor nuclei, consistent with its expression patterns in other animal species, whereas Oct-4 was abundantly expressed in equine SCNT blastocysts derived from the same donor cell line. Oct-4 transcripts were also detected in equine oocytes and whether any maternally inherited Oct-4 mRNA persisted up to the blastocyst stage was unclear in this study. We selected GDF9 to address this question; GDF9 was abundantly detected in equine oocytes, consistent with its expression pattern in mouse and bovine, but not detected in donor cells and cloned blastocysts, suggesting that the GDF9 mRNA from the oocyte was degraded at least by the blastocyst stage. The results from this study imply occurrence of Oct-4 reprogramming in equine SCNT blastocysts, and future analysis for more developmentally important genes is needed to better understand reprogramming at molecular levels in this species.


2009 ◽  
Vol 21 (1) ◽  
pp. 113 ◽  
Author(s):  
C. Couldrey ◽  
M. P. Green ◽  
D. N. Wells ◽  
R. S. F. Lee

Cloning of domestic animals by somatic cell nuclear transfer (SCNT) has permitted the rescue of valuable genetics and has the potential to allow rapid dissemination of desirable traits in production animals through the use of cloned sires. Whilst cloned animals may show developmental deviations and aberrant DNA methylation suggestive of incomplete nuclear reprogramming, it is widely accepted that their offspring are normal, as any aberrant epigenetic marks are believed to be corrected on passage of the genome through the germline. We assessed the extent of reprogramming by comparing DNA methylation patterns in sperm of SCNT bulls (n = 4) with sperm from bulls generated by AI (n = 5) and with the nuclear donor somatic cells (adult skin fibroblasts). The genomic regions examined were 3 repetitive sequences (satellites 1, 2, and alpha) and CpG islands in 5 genes [HAND1, LIT1, MASH2, IGF2, Dickkopf-1(DKK-1)]. Semen was collected from 16-month-old bulls and assessed for volume, sperm number, morphology, and motility. DNA was extracted from washed sperm and somatic donor cells, bisulfite-treated and processed for quantification of CpG methylation using the Sequenom MassArray system. Methylation levels at individual CpG sites/groups of CpGs were compared between sample groups using the t-test with pooled variances. No apparent difference was detected in semen characteristics between SCNT and AI bulls. Sperm DNA methylation levels were very low in single copy genes with the exception of the CpG island in IGF2, which has previously been shown to be completely methylated in sperm. At all genomic regions examined, each CpG site or CpG groups were methylated to different levels, and each region had a distinctive profile, which was almost invariant between individual sperm samples from either the SCNT or AI bulls. In all sites examined, there were no significant differences in methylation profiles between sperm from SCNT and AI bulls. In contrast, DNA methylation profiles were significantly different between SCNT bull sperm and the donor cells. The exception was the CpG island in MASH2, which was essentially unmethylated in both. For the 3 satellite sequences along with LIT1, HAND1, and to a lesser extent, the DKK-1 region, DNA was significantly less methylated in sperm than in the donor cells. Only IGF2 was significantly more methylated in SCNT and AI sperm than in the donor cells at 10/25 CpG sites (P < 0.02). The results indicate that gametes from SCNT bulls had different epigenotypes from the donor somatic cells. This is the first molecular evidence that donor cell genomes have been reprogrammed in these SCNT bulls and that after going through the germline had acquired DNA methylation profiles that were similar to AI-derived bulls. It also suggests that any epigenetic aberrations that SCNT bulls may harbor are unlikely to be passed on to their offspring through their gametes. Supported by FRST contract C10X0311.


2011 ◽  
Vol 23 (1) ◽  
pp. 247
Author(s):  
S. Y. Kim ◽  
S. H. Park ◽  
M. R. Lee ◽  
H. J. Eun ◽  
T. S. Kim ◽  
...  

The direct conversion of differentiated cells into undifferentiated or pluripotent cells would present scientific and medical benefits because of the potential for customized transplantation therapy. Although somatic cell nuclear transfer is one powerful way to fully reprogram somatic cells into a pluripotent state with the aid of oocyte or egg cytoplasm, the therapeutic applications of this approach have been hindered by technical complications as well as ethical objections. An alternative strategy for epigenetic reprogramming of differentiated cells into pluripotent status is desperately required. We have developed a reversible permeabilization protocol with digitonin to deliver sturgeon oocyte extract to porcine fibroblast cells ex ovo. Porcine fibroblasts were permeabilized by 4 μg mL–1 of digitonin for 2 min at 4°C and then incubated in sturgeon’s oocyte extract for 5 h at 15 to 18°C followed by resealing of the cell membrane. We found that the sturgeon’s oocyte extract induced the reduction of overall levels of tri-methylation at lysine 9 of histone H3 (H3K9Me3), which might be related to preservation of DNA methylation in fully differentiated cells, of porcine fibroblast cells. However, permeabilized porcine fibroblasts after treatment with the extract were increasingly acetylated at lysine 9 on histone 3 (H3K9Ac), which might be associated with expression of pluripotency genes. In addition, the cells treated with the extract showed up-regulation of Oct3/4, Sox2, and Nanog gene expression. When somatic cell nuclear transfer embryos reconstructed by using the treated donor cells were transferred into surrogates, the pregnancy rate was slightly high. These results showed that sturgeon’s oocyte extract can reprogram porcine somatic cells into undifferentiated status. Further work needs to exploit the epigenetic reprogramming of differentiated cells into the undifferentiated state using different species oocyte extract.


Zygote ◽  
2011 ◽  
Vol 20 (1) ◽  
pp. 67-72 ◽  
Author(s):  
So Gun Hong ◽  
Hyun Ju Oh ◽  
Jung Eun Park ◽  
Min Jung Kim ◽  
Geon A. Kim ◽  
...  

SummarySomatic cell nuclear transfer (SCNT) has emerged as an important tool for producing transgenic animals and deriving transgenic embryonic stem cells. The process of SCNT involves fusion of in vitro matured oocytes with somatic cells to make embryos that are transgenic when the nuclear donor somatic cells carry ‘foreign’ DNA and are clones when all the donor cells are genetically identical. However, in canines, it is difficult to obtain enough mature oocytes for successful SCNT due to the very low efficiency of in vitro oocyte maturation in this species that hinders canine transgenic cloning. One solution is to use oocytes from a different species or even a different genus, such as bovine oocytes, that can be matured easily in vitro. Accordingly, the aim of this study was: (1) to establish a canine fetal fibroblast line transfected with the green fluorescent protein (GFP) gene; and (2) to investigate in vitro embryonic development of canine cloned embryos derived from transgenic and non-transgenic cell lines using bovine in vitro matured oocytes. Canine fetal fibroblasts were transfected with constructs containing the GFP and puromycin resistance genes using FuGENE 6®. Viability levels of these cells were determined by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. Interspecies SCNT (iSCNT) embryos from normal or transfected cells were produced and cultured in vitro. The MTT measurement of GFP-transfected fetal fibroblasts (mean OD = 0.25) was not significantly different from non-transfected fetal fibroblasts (mean OD = 0.35). There was no difference between transgenic iSCNT versus non-transgenic iSCNT embryos in terms of fusion rates (73.1% and 75.7%, respectively), cleavage rates (69.7% vs. 73.8%) and development to the 8–16-cell stage (40.1% vs. 42.7%). Embryos derived from the transfected cells completely expressed GFP at the 2-cell, 4-cell, and 8–16-cell stages without mosaicism. In summary, our results demonstrated that, following successful isolation of canine transgenic cells, iSCNT embryos developed to early pre-implantation stages in vitro, showing stable GFP expression. These canine–bovine iSCNT embryos can be used for further in vitro analysis of canine transgenic cells and will contribute to the production of various transgenic dogs for use as specific human disease models.


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