TRIM28 maintains genome imprints and regulates development of porcine SCNT embryos

Reproduction ◽  
2021 ◽  
Vol 161 (4) ◽  
pp. 411-424
Author(s):  
Yanhui Zhai ◽  
Meng Zhang ◽  
Xinglan An ◽  
Sheng Zhang ◽  
Xiangjie Kong ◽  
...  
Keyword(s):  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Transcript Abundance ◽  
Dna Demethylation ◽  
Epigenetic Variability ◽  
Promoter Regions ◽  
Cell Stage ◽  
Genome Wide ◽  
Developmental Progression ◽  
Imprinting Gene

Pre-implantation embryos undergo genome-wide DNA demethylation, however certain regions, like imprinted loci remain methylated. Further, the mechanisms ensuring demethylation resistance by TRIM28 in epigenetic reprogramming remain poorly understood. Here, TRIM28 was knocked down in oocytes, and its effects on porcine somatic cell nuclear transfer (SCNT) embryo development was examined. Our results showed that SCNT embryos constructed from TRIM28 knockdown oocytes had significantly lower cleavage (53.9 ± 3.4% vs 64.8 ± 2.7%) and blastocyst rates (12.1 ± 4.3% vs 19.8 ± 1.9%) than control-SCNT embryos. The DNA methylation levels at the promoter regions of the imprinting gene IGF2 and H19 were significantly decreased in the 4-cell stage, and the transcript abundance of other imprinting gene was substantially increased. We also identified an aberrant two-fold decrease in the expression of CXXC1and H3K4me3 methyltransferase (ASH2L and MLL2), and the signal intensity of H3K4me3 had a transient drop in SCNT 2-cell embryos. Our results indicated that maternal TRIM28 knockdown disrupted the genome imprints and caused epigenetic variability in H3K4me3 levels, which blocked the transcription activity of zygote genes and affected the normal developmental progression of porcine SCNT embryos.

scholarly journals Dynamic Methylation Changes of DNA and H3K4 by RG108 Improve Epigenetic Reprogramming of Somatic Cell Nuclear Transfer Embryos in Pigs

2018 ◽  
Vol 50 (4) ◽  
pp. 1376-1397 ◽  
Author(s):  
Yanhui Zhai ◽  
Zhiren Zhang ◽  
Hao Yu ◽  
Li Su ◽  
Gang Yao ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Somatic Cell ◽  
Histone Modifications ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Histone H3 ◽  
Dna Demethylation ◽  
Epigenetic Reprogramming ◽  
Expression Levels ◽  
Fetal Fibroblasts

Background/Aims: DNA methylation and histone modifications are essential epigenetic marks that can significantly affect the mammalian somatic cell nuclear transfer (SCNT) embryo development. However, the mechanisms by which the DNA methylation affects the epigenetic reprogramming have not been fully elucidated. Methods: In our study, we used quantitative polymerase chain reaction (qPCR), Western blotting, immunofluorescence staining (IF) and sodium bisulfite genomic sequencing to examine the effects of RG108, a DNA methyltransferase inhibitor (DNMTi), on the dynamic pattern of DNA methylation and histone modifications in porcine SCNT embryos and investigate the mechanism by which the epigenome status of donor cells’ affects SCNT embryos development and the crosstalk between epigenetic signals. Results: Our results showed that active DNA demethylation was enhanced by the significantly improving expression levels of TET1, TET2, TET3 and 5hmC, and passive DNA demethylation was promoted by the remarkably inhibitory expression levels of DNMT1, DNMT3A and 5mC in embryos constructed from the fetal fibroblasts (FFs) treated with RG108 (RG-SCNT embryos) compared to the levels in embryos from control FFs (FF-SCNT embryos). The signal intensity of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 9 acetylation (H3K9Ac) was significantly increased and the expression levels of H3K4 methyltransferases were more than 2-fold higher expression in RG-SCNT embryos. RG-SCNT embryos had significantly higher cleavage and blastocyst rates (69.3±1.4%, and 24.72±2.3%, respectively) than FF-SCNT embryos (60.1±2.4% and 18.38±1.9%, respectively). Conclusion: Dynamic changes in DNA methylation caused by RG108 result in dynamic alterations in the patterns of H3K4me3, H3K9Ac and histone H3 lysine 9 trimethylation (H3K9me3), which leads to the activation of embryonic genome and epigenetic modification enzymes associated with H3K4 methylation, and contributes to reconstructing normal epigenetic modifications and improving the developmental efficiency of porcine SCNT embryos.

24 EFFECTS OF HISTONE METHYLATION RELATED GENES ON EPIGENETIC REPROGRAMMING AND ZYGOTIC GENE ACTIVATION IN OVINE SOMATIC CELL NUCLEAR TRANSFER (SCNT) EMBRYOS

2009 ◽  
Vol 21 (1) ◽  
pp. 112
Author(s):  
I. Choi ◽  
K. H. S. Campbell
Keyword(s):  
Cell Cycle ◽  
Somatic Cell ◽  
Embryo Development ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Gene Activation ◽  
Early Embryo ◽  
Cell Stage ◽  
Early Embryo Development ◽  
Zygotic Gene

After fertilization, early embryo development is dependent upon maternally inherited proteins and protein synthesised from maternal mRNA until zygotic gene activation (ZGA) occurs. The transition of transcriptional activity from maternal to embryonic control occurs with the activation of rRNA genes and the formation of the nucleolus at the 8- to 16-cell stage that coincides with a prolonged fourth cell cycle in bovine and ovine embryos. However, previous studies have reported a shift in the longest cell cycle (fifth cell cycle) in bovine somatic cell nuclear transfer (SCNT) embryos, suggesting that the major genome activation is delayed, possibly due to incomplete changes in chromatin structure such as hypermethylation and hypoacetylation of histone (Memili and First 2000 Zygote 8, 87–96; Holm et al. 2003 Cloning Stem Cells 5, 133–142). Although global gene expression profile studies have been carried out in somatic cell nuclear transfer embryos, little is known about the expression of genes which can alter chromatin structure in early embryo development and possibly effect ZGA. To determine whether epigenetic reprogramming of donor nuclei affected ZGA and expression profiles in SCNT embryos, ZBTB33 (zinc finger and BTB domain containing 33, also known as kaiso, a methy-CpG specific repressor), BRG1(brahma-related gene 1, SWI/SNF family of the ATP-dependent chromatin remodeling complexes), JMJD1A (jumonji domain containing 1A, H3K9me2/1-specific demethylase), JMJD1C (putative H3K9-specific demethylase), and JMJD2C (H3K9me3-specific demethylase) were examined by RT-PCR at different developmental stages [germinal vesicle (GV), metaphase II (MII), 8- to 16-cell, 16- to 32-cell, and blastocyst in both parthenogenetic and SCNT embryos]. All genes were detected in parthenogenetic and SCNT blastocyts, and ZBTB33 was also expressed in all embryos at all stages tested. However, the onset of expression of JMJD1C, containing POU5F1 binding site at 5′-promoter region and BRG1 required for ZGA are delayed in SCNT embryos as compared to parthenotes (16- v. 8-cell, and blastoocyst v. 16-cell stage). Furthermore, JMJD2C containing NANOG binding sites at the 3′-flanking region was expressed in GV and MII oocytes and parthenogenetic blastocysts, whereas in SCNT embryos, JMJD2C was only observed from the 16-cell stage onwards. Interestingly, JMJD1A, which is positively regulated by POU5F1, was not detected in GV and MII oocytes but was present in blastocyst stage embryos of both groups. Taken together, these results suggest that incomplete epigenetic modifications of genomic DNA and histones lead to a delayed onset of ZGA which may affect further development and establishment of totipotency. Subsequently, aberrant expression patterns reported previously in SCNT embryos may be attributed to improper expression of histone H3K9 and H3K4 demethylase genes during early embryo development.

185 DEVELOPMENT CAPACITY OF PRE- AND POSTPUBERTAL PIG OOCYTES EVALUATED BY SOMATIC CELL NUCLEAR TRANSFER AND PARTHENOGENETIC ACTIVATION

2013 ◽  
Vol 25 (1) ◽  
pp. 241 ◽  
Author(s):  
H. S. Pedersen ◽  
R. Li ◽  
Y. Liu ◽  
P. Løvendahl ◽  
P. Holm ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Cell Number ◽  
Time Interval ◽  
Cell Stage ◽  
Parthenogenetic Activation ◽  
Development Capacity ◽  
Developmental Capacity

Most of the porcine oocytes used for in vitro studies are collected from gilts. Our aims were to study development capacity of gilt v. sow oocytes (pre- and postpubertal respectively) using 2 techniques illustrating development competence [parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT)], and to describe a simple method to select the most competent oocytes. Inside-ZP diameter of in vitro-matured gilt oocytes was measured (µm; small ≤110; medium >110; large ≥120). Gilt and sow oocytes were morphologically grouped as good (even cytoplasm, smooth cell membrane, visible perivitelline space) or bad before used for PA (good and bad) or SCNT (good). The PA and SCNT were performed as before with minor modifications (Cryobiol. 64, 60; Cell. Reprogr. 13, 521) before culture for 6 days in a standard or timelapse incubator. Rates of cleavage (CL%, Day 2), blastocyst (BL%, Day 6), and blastocyst cell number (Hoechst 33342) were recorded. For PA embryos in a timelapse incubator (26 oocytes/group; 2 replicates), the first appearance of 2-cell stage was recorded. Between groups, CL% and BL% were analysed by chi-square and cell number by t-test. Results are presented in the table for the development of good oocytes after PA. The results show a low CL% of small-gilts compared with the other groups. The BL% increased with gilt-oocyte-diameter; however, sow oocytes reached the highest BL%. Total cell number was higher in sow than in gilt blastocysts. The SCNT experiments showed no differences in CL% (90–96) and blastocyst cell number (51–59) between groups. The BL% was higher in medium gilts and sows (41; 45) compared with large gilts (21). The BL% of bad oocytes was 1% from all 4 groups (176 oocytes, 25 replicates). Time interval for appearance of 2-cell stage for embryos developing into blastocysts showed no differences between groups (19–20 h). Within groups, this time interval showed a larger standard deviation for embryos not developing v. embryos developing into blastocysts. It is concluded that (a) sow oocytes have higher developmental capacity compared to gilts, (b) small gilt oocytes are not developmentally competent, (c) measurement of inside-ZP diameter, combined with morphological selection, is useful to remove non-competent oocytes. Further studies are needed to dissect the developmental capacity of medium and large gilt oocytes. Also, further timelapse studies may reveal a time interval in which the first cleavage of embryos with high developmental capacity takes place. Table 1.Rates of cleavage (CL%), blastocyst (BL%), and total no. of cells (mean ± SEM) in blastocysts of PA embryos from gilts and sows1

65 BLASTOCYSTS DERIVED FROM ADULT FIBROBLASTS OF RHESUS MONKEY (MACACA MULATTA) USING INTERSPECIES SOMATIC CELL NUCLEAR TRANSFER

2010 ◽  
Vol 22 (1) ◽  
pp. 191
Author(s):  
D. K. Kwon ◽  
J. T. Kang ◽  
S. J. Park ◽  
M. N. L. Gomez ◽  
S. J. Kim ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Somatic Cell ◽  
Macaca Mulatta ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Embryonic Stem ◽  
Developmental Rate ◽  
Cell Stage ◽  
Nuclear Number

Interspecies somatic cell nuclear transfer (iSCNT) has alternatively chosen in primate SCNT because of the difficulty in collecting enough oocytes for research. The purpose of this experiment is to produce iSCNT-derived blastocysts using enucleated cow (Bos taurus) metaphase II oocytes and adult rhesus monkey (Macaca mulatta) fibroblasts. Ear skin tissueofrhesus monkey (male, 6 years old) was collected by biopsy and fibroblasts were isolated. Immature COCs from cow ovaries were collected and matured in vitro in TCM-199. Squish enucleation was done in the presence of bisbenzimide and cytochalasin B. After enucleation, a single rhesus monkey somatic cell was injected into the perivitelline space of an enucleated oocyte through the slit in the zona pellucida made during enucleation. Subsequently, the rhesus monkey somatic cell and cow oocyte membranes were electrically fused. The nonactivated interspecies cloned couplets were cultured for 2 h to allow reprogramming to occur. Then, couplets were activated using a 2-step protocol consisting of treatment with 5 μM ionomycin for 4 to 5 min and subsequently with 2mM 6-DMAP for 4 h. Activated iSCNT embryos were cultured for 10 days inmodified SOF with various conditions (at 37 to39°C, 5 to 5.5% CO2 and 5 to 20% O2) to examine the effects ofIVC conditions. As a results, most embryos were arrested at the 8- to 16-cell stage and only 3 blastocysts were derived from rhesus monkey iSCNT. The blastocyst developmental rate was 0.26% generated from the total IVC activated interspecies embryos (n = 1153). Among the 3 blastocysts, 2 of them were used for counting nuclear number using bisbenzimide staining. The nuclear number of the 2 iSCNT-derived blastocysts was 51 and 24, respectively. The other iSCNT-derived blastocyst was used for analyzing mitochondrial (mt)DNAto confirm that it contained both cow and rhesus monkey mtDNA. As a result, mtDNA from both rhesus monkey and cow were detected inPCR analysis. The band intensity was more dominant for cow mtDNA than for rhesus monkey mtDNA. Although the blastocyst developmental rate is extremely low, it is confirmed that two phylogenetically distant species including primate could develop in vitro until the blastocyst stage by iSCNT. The in vitro developmental system of this rhesus monkey iSCNT-derived blastocysts provides a platform for further improvement of developmental rate and quality of rhesus monkey iSCNT-derived blastocysts. It also provides an opportunity to establish rhesus monkey iSCNT-derived embryonic stem cell lines for study of rhesus monkey nucleus and cow mitochondria interaction mechanisms during early developmental stages. This study was financially supported by the Korean MEST, through the BK21 program for Veterinary Science, and SNU foundation (Benefactor; RNL Bio).

scholarly journals The Influence of Interspecies Somatic Cell Nuclear Transfer on Epigenetic Enzymes Transcription in Early Embryos

2016 ◽  
Vol 39 (2) ◽  
pp. 209-217 ◽  
Author(s):  
Martin Morovic ◽  
Matej Murin ◽  
Frantisek Strejcek ◽  
Michal Benc ◽  
Dusan Paál ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Coming Out ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Dna Methyltransferase ◽  
Dna Methyltransferases ◽  
Preimplantation Embryos ◽  
Mammalian Development ◽  
Cell Stage ◽  
Early Embryos

AbstractOne of the main reason for the incorrect development of embryos derived from somatic cell nuclear transfer is caused by insufficient demethylation of injected somatic chromatin to a state comparable with an early embryonic nucleus. It is already known that the epigenetic enzymes transcription in oocytes and early embryos of several species including bovine and porcine zygotes is species-dependent process and the incomplete DNA methylation correlates with the nuclear transfer failure rate in mammals. In this study the transcription of DNA methyltransferase 1 and 3a (DNMT1, DNMT3a) genes in early embryonic stages of interspecies (bovine, porcine) nuclear transfer embryos (iSCNT) by RT-PCR were analyzed. Coming out from the diverse timing of embryonic genome activation (EGA) in porcine and bovine preimplantation embryos, the intense effect of ooplasm on transferred somatic cell nucleus was expected. In spite of the detection of ooplasmic DNA methyltransferases, the somatic genes for DNMT1 and DNMT3a enzymes were not expressed and the development of intergeneric embryos stopped at the 4-cell stage. Our results indicate that the epigenetic reprogramming during early mammalian development is strongly influenced by the ooplasmic environment.

TRIM28 down-regulation on methylation imprints in bovine preimplantation embryos

Zygote ◽  
2018 ◽  
Vol 26 (6) ◽  
pp. 449-456 ◽  
Author(s):  
Xin Ma ◽  
Sheng Zhang ◽  
Meiling Zhang ◽  
Yiran Zhu ◽  
Panpan Ma ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Preimplantation Embryos ◽  
Differentially Methylated Region ◽  
Fibroblast Cells ◽  
Mrna Sequence ◽  
Cell Stage ◽  
H19 Gene

SummaryTRIM28/KAP1/TIF1β was identified as a universal transcriptional co-repressor and is critical for regulating post-fertilization methylation reprogramming in preimplantation embryos. In this study, three siRNAs (si647, si742, and si1153) were designed to target the TRIM28 mRNA sequence. After transfection of the mixture of the three siRNA (siMix) into bovine fibroblast cells, the most effective one for TRIM28 knockdown was selected. By injecting RNAi directed against TRIM28 mRNA, we found that TRIM28 knockdown in oocytes had the most effect on the H19 gene, in which differentially methylated region (DMR) methylation was almost completely absent at the 2-cell stage (1.4%), while control embryos showed 74% methylation. In addition, global H3K9me3 levels at the 2-cell stage were significantly higher in the in vitro fertilization (IVF) group than in the TRIM28 knockdown group (P<0.05). We further show that TRIM28 is highly expressed during oocyte maturation and reaches peak levels at the 2-cell stage. In contrast, at this stage, TRIM28 expression in somatic cell nuclear transfer (SCNT) embryos decreased significantly (P<0.05), suggesting that Trim28 transcripts are lost during SCNT. TRIM28 is required for the maintenance of methylation imprints in bovine preimplantation embryos, and the loss of TRIM28 during SCNT may contribute to the unfaithful maintenance of imprints in cloned embryos.

61 BOVINE OOPLASM PARTIALLY REMODELS CHIMPANZEE SOMATIC NUCLEI FOLLOWING SOMATIC CELL NUCLEAR TRANSFER

2008 ◽  
Vol 20 (1) ◽  
pp. 111
Author(s):  
K. Wang ◽  
Z. Beyhan ◽  
R. Rodriguez ◽  
P. J. Ross ◽  
A. Lager ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Chromatin Remodeling ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Bisulfite Sequencing ◽  
Domestic Cat ◽  
Pcr Analysis ◽  
Cell Stage ◽  
Somatic Nucleus ◽  
Atp Levels

Interspecies somatic cell nuclear transfer (iSCNT) is a tool to address basic questions related to nucleus–cytoplasm interactions between different species. This approach may have practical applications, such as endangered species preservation. To date, live offspring have been obtained only when closely related species were used, such as cow/gaur, cow/buffalo, and domestic cat/wild cat. Several groups have reported preimplantation development of iSCNT embryos using a diverse collection of species; however, further development of these embryos either failed or was not reported. The aim of this study was to investigate developmental events that take place during reprogramming of a somatic nucleus in an enucleated oocyte from a distant species. Our experimental model was cow/chimpanzee iSCNT. We confirmed the donor cell genome origin in SCNT embryos by karyotyping. Embryonic genome activation (EGA) was monitored by Br-UTP incorporation assay and RT-PCR analysis of 6 genes. Chromatin remodeling events such as histone acetylation, histone methylation, and DNA methylation were observed by immunocytochemistry along with examination of Oct4 and Nanog promoter methylation by bisulfite sequencing. As an indicator of embryonic metabolism, ATP levels and apoptotic status of embryonic nuclei were determined by ATP detection and TUNEL assays, respectively. Development of iSCNT embryos did not progress beyond the 8- to 16-cell stage, whereas their cow/cow SCNT counterparts readily developed to the blastocyst stage. Karyotype analysis showed a donor-specific, diploid genomic content in most of the iSCNT nuclei (46 chromosomes). Major EGA takes place at the 16- and 8-cell stages in cow and chimpanzee embryos, respectively. However, our analyses showed a partial EGA pattern in iSCNT embryos at the 8-cell stage, as indicated by lower levels of Br-UTP incorporation and irregular expression of certain embryonic genes compared to that in cow/cow SCNT embryos. GAPDH, Oct4, and Stella transcripts were detected, while Nanog, Glut1, and DSC2 genes failed to be expressed in chimpanzee somatic nuclei, as opposed to robust expression observed for all 6 genes in bovine SCNT embryos. Dynamic chromatin remodeling events as monitored by H3K27 methylation and H4K5 acetylation-specific antibodies were similar in both intra- and interspecies SCNT embryos from 1-cell to 8–16-cell stages. A global demethylation pattern was observed in iSCNT embryos from 1-cell to 8–16-cell stages, which was not significantly different from that of bovine SCNT embryos by immunocytochemistry. However, bisulfite sequencing indicated incomplete demethylaton of Oct4 and Nanog promoters in 8-cell iSCNT embryos, unlike the complete demethylation of the same promoter regions observed in their bovine intraspecific counterparts. ATP levels were significantly higher in bovine SCNT embryos than in iSCNT embryos; TUNEL assay did not reveal any difference in apoptotic status of the nuclei from both types of embryos. Collectively, our results suggest that bovine ooplasm can partially remodel chimpanzee somatic nuclei. However, the remodeling activity was not sufficient to drive embryo development past the 8–16-cell stage.

45 The role of TRIM28 in porcine somatic cell nuclear transfer embryo development

2019 ◽  
Vol 31 (1) ◽  
pp. 148
Author(s):  
Y. H. Zhai ◽  
X. L. An ◽  
Z. R. Zhang ◽  
S. Zhang ◽  
Z. Y. Li
Keyword(s):  
Dna Methylation ◽  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Chromatin Modification ◽  
Blastocyst Stage ◽  
Imprinted Genes ◽  
Cell Stage ◽  
Genomic Methylation

During fertilization, the parental genome undergoes extensive demethylation. Global DNA demethylation is a hallmark of epigenetic reprogramming. Embryos engage non-canonical DNA methylation maintenance mechanisms to ensure inheritance of exceptional germline features. However, the mechanisms ensuring demethylation resistance in light of global reprogramming remain poorly understood. TRIM28 is a maternal-effect factor that controls genomic imprinting during early embryonic reprogramming. In this study, cytoplasmic injections of siRNA were performed into oocytes matured in vitro for 26h to interfere with the expression of TRIM28 in oocytes. The injected oocytes were continually matured in vitro until 42h and used to construct somatic cell nuclear transfer (SCNT) embryos. During 2-cell to blastocyst stages, the expression of development-related genes (NANOG, POU5F1, CDX2, BAX, and BCL2), maternal imprinting genes (IGF2, DIO3, PLAGL1, and DLK1), paternal imprinting genes (H19 and PEG3), TRIM28-recruitment complex-associated genes (ZFP57, PGC7, SETDB1, and DNMT), and epigenetic chromatin modification enzymes were detected by quantitative PCR in the constructed TRIM28-interfered SCNT embryos. The DNA methylation levels in the promoter regions of the imprinted genes (H19 and IGF2) and chromatin repeats (PRE-1 and SATELLITE) were analysed by sodium bisulfite genomic sequencing. The results showed that the TRIM28-interfered SCNT embryos had significantly lower cleavage and blastocyst rates (53.9±3.4% and 12.1±4.3%, respectively) than those in control SCNT embryos (64.8±2.7% and 18.8±1.9%, respectively). The expression levels of development-related genes (NANOG and POU5F1) and TRIM28-recruited transcriptional repression complex-associated genes (PGC7, ZFP57, and DNMT1) in the 4-cell stage were significantly reduced (P&lt;0.05). The imprinted genes were significantly up-regulated (P&lt;0.05) from the 2-cell to blastocyst stage in constructed TRIM28-interfered SCNT embryos, except H19 at the 2-cell and blastocyst stage decreased remarkably (P&lt;0.05). The DNA methylation levels of IGF2 decreased 2-fold from the 2-cell to blastocyst stage in TRIM28-interfered SCNT embryos. The PRE-1 and SATELLITE had a remarkably lower (P&lt;0.05) methylation levels in the TRIM28-interfered 2-cell embryos than in control SCNT embryos. The cluster analysis showed some of the chromatin modification enzymes had abnormal expression in the TRIM28-interfered SCNT embryos, especially in the 8-cell stage, where 48 enzymes were significantly decreased (P&lt;0.05). The down-regulation enzymes were mainly clustered in the histone H3K4 methyl transferase and histone acetylase. These results indicate that down-regulation of maternal TRIM28 breaks the steady-state of genomic methylation at a particular locus of the imprinted gene, disrupts the expression of imprinted gene and epigenetic modifications enzymes, and is detrimental to normal development of SCNT embryos. Maternal TRIM28 is needed in maintaining a stable state of genomic methylation and epigenetic modification state during SCNT embryo development.

scholarly journals Phosphorylated histone H2A.x in porcine embryos produced by IVF and somatic cell nuclear transfer

Reproduction ◽  
2013 ◽  
Vol 146 (4) ◽  
pp. 325-333 ◽  
Author(s):  
Rodrigo C Bohrer ◽  
Limei Che ◽  
Paulo B D Gonçalves ◽  
Raj Duggavathi ◽  
Vilceu Bordignon
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Chloride Ion ◽  
Dna Integrity ◽  
Strontium Chloride ◽  
Oocyte Activation ◽  
Dna Double Strand Breaks ◽  
Cell Stage

Phosphorylated histone H2A.x (H2AX139ph) is a key factor for the repair of DNA double-strand breaks (DSBs) and the presence of H2AX139ph foci indicates the sites of DSBs. In this study, we characterized the presence of H2AX139ph during in vitro development of porcine embryos produced by IVF and somatic cell nuclear transfer (SCNT). Pronuclear stage embryos produced by IVF had, on average, 9.2 H2AX139ph foci per pronucleus. The number of H2AX139ph foci was higher in the 2-cell-stage embryos than in the 4-cell-stage embryos fixed at 48 h post-fertilization. The percentage of H2AX139ph-positive nuclei was higher in SCNT embryos that were activated with ionomycin (ION) alone than in those activated with ION and strontium chloride (ION+Sr2+). A negative correlation was found between the percentage of H2AX139ph-positive cells and the total number of cells per embryo in day 7 blastocysts produced by IVF or SCNT. Based on the detection of H2AX139ph foci, the findings of this study indicate that DSBs occur in a high proportion of porcine embryos produced by either IVF or SCNT; fast-cleaving embryos have fewer DSBs than slow-cleaving embryos; the oocyte activation protocol can affect DNA integrity in SCNT embryos; and better-quality blastocysts have fewer DSBs. We propose that the presence of H2AX139ph foci can be a useful marker of embryo quality.

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