Dataset Information

Characterization of X-Chromosome Gene Expression in Bovine Blastocysts Derived by In vitro Fertilization and Somatic Cell Nuclear Transfer.

ABSTRACT: To better understand X-chromosome reactivation (XCR) during early development, we analyzed transcriptomic data obtained from bovine male and female blastocysts derived by in-vitro fertilization (IVF) or somatic-cell nuclear transfer (SCNT). We found that X-linked genes were upregulated by almost two-fold in female compared with male IVF blastocysts. The upregulation of X-linked genes in female IVFs indicated a transcriptional dimorphism between the sexes, because the mean autosomal gene expression levels were relatively constant, regardless of sex. X-linked genes were expressed equivalently in the inner-cell mass and the trophectoderm parts of female blastocysts, indicating no imprinted inactivation of paternal X in the trophectoderm. All these features of X-linked gene expression observed in IVFs were also detected in SCNT blastocysts, although to a lesser extent. A heatmap of X-linked gene expression revealed that the initial resemblance of X-linked gene expression patterns between male and female donor cells turned sexually divergent in host SCNTs, ultimately resembling the patterns of male and female IVFs. Additionally, we found that sham SCNT blastocysts, which underwent the same nuclear-transfer procedures, but retained their embryonic genome, closely mimicked IVFs for X-linked gene expression, which indicated that the embryo manipulation procedure itself does not interfere with XCR in SCNT blastocysts. Our findings indicated that female SCNTs have less efficient XCR, suggesting that clonal reprogramming of X chromosomes is incomplete and occurs variably among blastocysts, and even among cells in a single blastocyst.

SUBMITTER: Min B

PROVIDER: S-EPMC5385346 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Characterization of X-Chromosome Gene Expression in Bovine Blastocysts Derived by <i>In vitro</i> Fertilization and Somatic Cell Nuclear Transfer.

Min Byungkuk B Park Jung Sun JS Jeon Kyuheum K Kang Yong-Kook YK

Frontiers in genetics 20170410

To better understand X-chromosome reactivation (XCR) during early development, we analyzed transcriptomic data obtained from bovine male and female blastocysts derived by <i>in-vitro</i> fertilization (IVF) or somatic-cell nuclear transfer (SCNT). We found that X-linked genes were upregulated by almost two-fold in female compared with male IVF blastocysts. The upregulation of X-linked genes in female IVFs indicated a transcriptional dimorphism between the sexes, because the mean autosomal gene e ...[more]

PMID: 28443134

Similar Datasets

Project description:Incomplete epigenetic reprogramming is postulated to contribute to the low developmental success following somatic cell nuclear transfer (SCNT). Here, we describe the epigenetic reprogramming of DNA methylation at an alpha satellite I CpG site (αsatI-5) during development of cattle generated either by artificial insemination (AI) or in vitro fertilization (IVF) and SCNT. Quantitative methylation analysis identified that SCNT donor cells were highly methylated at αsatI-5 and resulting SCNT blastocysts showed significantly more methylation than IVF blastocysts. At implantation, no difference in methylation was observed between SCNT and AI in trophoblast tissue at αsatI-5, however, SCNT embryos were significantly hyper-methylated compared to AI controls at this time point. Following implantation, DNA methylation at αsatI-5 decreased in AI but not SCNT placental tissues. In contrast to placenta, the proportion of methylation at αsatI-5 remained high in adrenal, kidney and muscle tissues during development. Differences in the average proportion of methylation were smaller in somatic tissues than placental tissues but, on average, SCNT somatic tissues were hyper-methylated at αsatI-5. Although sperm from all bulls was less methylated than somatic tissues at αsatI-5, on average this site remained hyper-methylated in sperm from cloned bulls compared with control bulls. This developmental time course confirms that epigenetic reprogramming does occur, at least to some extent, following SCNT. However, the elevated methylation levels observed in SCNT blastocysts and cellular derivatives implies that there is either insufficient time or abundance of appropriate reprogramming factors in oocytes to ensure complete reprogramming. Incomplete reprogramming at this CpG site may be a contributing factor to low SCNT success rates, but more likely represents the tip of the iceberg in terms of incompletely reprogramming. Until protocols ensure the epigenetic signature of a differentiated somatic cell is reset to a state resembling totipotency, the efficiency of SCNT is likely to remain low.

Project description:Since the first cloned animal Dolly Sheep was successfully created by using somatic cell nuclear transfer(SCNT) technique. It has become an irreplaceable tool to understand nuclear reprogramming and totipotency and holds huge potentials for regenerative medicine. However, extremely poor development rate of SCNT embryos indicates it is still questionable. The nature of reprogramming oocyte factors and their mechanism of action remain largely unknown.It is evident that the major barrier that hinders the developing iSCNT embryo mainly appears at the time of embryonic genome activation (EGA), which primarily occurs at the eight-cell stage in mammalian. The interspecies somatic cell nuclear transfer (iSCNT) is desired model for nuclear reprogramming research and a powerful tool for discovering the master genome activation genes. In this study, a valuable transcriptome recourse of iSCNT embryos was established, which derived from more than 2000 clone embryos of four different inter-family donor cells. Based on weighted gene co-expression network (WGCNA) approach, we provide an extensive transcriptome analysis of differentially expressed genes(DEG) for iSCNT embryos. The total gene expression patterns of different iSCNT embryos were discussed. 26 cell-specific modules with were identified, and those module significance and GO enriched categories were analyzed. The regulatory pathways of reprogramming barriers were further enriched. As master genome trigger genes, the transcripts related to TFIID subunit, RNA polymerase and Mediator were incomplete activated in iSCNT embryos. This indicated that pioneer factors, present in the cytoplasm of the oocyte, were failed to bind the sequence target on the heterology nuclear genome. This genomic incompatibility between the nuclear donor cell and the cytoplast may be as a major contributing factor causes the developmental failure of iSCNT cloned embryos. This study demonstrates that the iSCNT embryos undergoes only partial or incomplete reprogramming at eight-cell stage in mammalian. Our results offered convincing evidence that the abnormal expression of key master pathways may be caused the embryo developmental block of cloning embryo. This work will contribute to a better understanding of the molecular interaction between nuclear–cytoplasmic interaction and provides insight into the molecular determinants of nuclear reprogramming, human embryonic stem cell (hESC)-based therapies and rescuing highly endangered species.

Project description:Although somatic cell nuclear transfer (SCNT) cloning is more efficient in bovine than in all other species tested so far, there is a high rate of pregnancy failure that has been linked to structural and functional abnormalities of the placenta. We tested the hypothesis that these changes may originate from disturbed embryo-maternal interactions in the pre-implantation period. Therefore, we evaluated the transcriptome response of the endometrium to SCNT embryos (produced from five different donor cell cultures) as compared to embryos derived from in vitro fertilization (IVF). SCNT embryos and IVF embryos were cultured under identical conditions to the blastocyst stage (Day 8) and transferred to recipients. The recipients were slaughtered at day 18 of pregnancy and the uterus was recovered. Pregnancy was verified by the presence of at least one normally developed embryo. Transcriptome profiling of endometrium samples using a custom cDNA microarray covering transcripts expressed in the endometrium and/or oviduct epithelium revealed 58 transcripts that were differently abundant between endometrium samples from SCNT vs. IVF pregnancies. Prominent examples are NR2F2 (encoding the orphan nuclear receptor COUP-TFII) and GJA1 (encoding connexin 43). Both transcripts are known to play important roles in placentation and were significantly less abundant in endometrium from SCNT vs. IVF pregnancies. These findings suggest that placental failure in bovine clone pregnancies may originate from abnormal embryo-maternal communication already in the pre- or peri-implantation period. Endometrium transcriptome profiles may serve as a novel readout to evaluate SCNT embryos for their ability to induce pregnancy with a functional placenta. Keywords: response to different embryos Nineteen German Fleckvieh (Simmental) heifers were slaughtered at day 18 of pregnancy. Cycle-synchronized recipient heifers received either IVP or SCNT embryos at day 7 of the estrous cycle. Animals were slaughtered at day 18. Endometrial (intercaruncular) tissue samples were obtained from 10 pregnant animals after transfer of IVP embryos and from 9 pregnant animals after transfer of SCNT embryos.

Dataset Information

Characterization of X-Chromosome Gene Expression in Bovine Blastocysts Derived by In vitro Fertilization and Somatic Cell Nuclear Transfer.

Publications

Characterization of X-Chromosome Gene Expression in Bovine Blastocysts Derived by <i>In vitro</i> Fertilization and Somatic Cell Nuclear Transfer.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets