Abnormal Regulation of DNA Methyltransferase Expression in Cloned Mouse Embryos1

Chung, Young Sun; Ratnam, Sarayu; Chaillet, J. Richard; Latham, Keith E.

doi:10.1095/biolreprod.102.014076

Cited by 139 publications

(80 citation statements)

References 27 publications

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“…Based on the reports that most NT embryos cease development at the pre-and peri-implantation stages [1,41], it is probable that the accumulation of different abnormalities observed in NT embryos at various developmental stages, such as failure to erase some of the features of donor cells [42][43][44], abnormal gene expression [4,8,10,25,[45][46][47], abnormal DNA methylation [4][5][6], abnormal formation of placentae [1,41,[48][49][50], and the abnormalities detected in this study, leads to gradual loss of NT embryos. Abnormalities that have not been detected in previous studies and/or small differences in gene expression may seriously affect embryonic development.…”

Section: Discussionmentioning

confidence: 72%

Comparison of the RNA Polymerase I-, II- and III-Dependent Transcript Levels Between Nuclear Transfer and In Vitro Fertilized Embryos at the Blastocyst Stage

Suzuki

Minami

Kono

et al. 2007

Journal of Reproduction and Development

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Abstract. Cloned animals have been produced in several mammalian species so far, although success rates to term are very low. Aberrations in gene expression derived from abnormal epigenetic status have been thought to be a cause of developmental abnormalities in clones, and several abnormalities in gene expression have already been detected in cloned animals and embryos. In this study, we examined the hypothesis that the poor survival rates of nuclear transfer (NT) embryos are partly due to aberrations in the regulation of expression of genes transcribed by RNA polymerases I and III, in addition to polymerase II. We produced cloned and in vitro fertilized mouse embryos that developed to the blastocyst stage, and the amounts of several genes were analyzed using individual embryos. We found that the amounts of mature 18S ribosomal RNA (rRNA) transcribed by RNA polymerase I were lower in NT embryos than in IVF embryos, but that the amounts of 47S rRNA and intermediates of mature rRNAs were higher in NT embryos. In addition, the amount of 7SK RNA transcribed by RNA polymerase III was lower in NT embryos than in IVF embryos. The transcripts of all but one of the genes transcribed by RNA polymerase II were not noticeably different between NT and IVF embryos. These results suggest that some of the transcripts produced by RNA polymerases I, II and III are aberrantly regulated in NT embryos.

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Section: Discussionmentioning

confidence: 72%

Comparison of the RNA Polymerase I-, II- and III-Dependent Transcript Levels Between Nuclear Transfer and In Vitro Fertilized Embryos at the Blastocyst Stage

Suzuki

Minami

Kono

et al. 2007

Journal of Reproduction and Development

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“…Kwon et al [46] also found global hypermethylated DNA at the 4-cell stage of porcine SCNT embryos compared with IVF embryos using a 5-methylcytosine (5-MeC) antibody immunostaining method. An abnormally increased expression of Dnmt1 protein has also been observed in the 8-cell stage cloned murine embryos reconstructed from cumulus cells [47]. These abnormal levels of embryonic methylation may be associated with reduced developmental potential [48].…”

Section: Discussionmentioning

confidence: 92%

Analysis of apoptosis and methyltransferase mRNA expression in porcine cloned embryos cultured in vitro

Ren

Lü

et al. 2010

J Assist Reprod Genet

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Purpose The purpose of this study was to investigate the relationship of porcine somatic cell nuclear transfer (SCNT) embryo developmental competence with embryonic cell apoptosis and DNA methylation. Methods The apoptotic incidence was examined via comet assay, and the mRNA expression of genes implicated in apoptosis (Bcl-2) and DNA methylation (Dnmt1, Dnmt3a) was determined using real-time RT-PCR. Results Comet assay showed that the SCNT embryos exhibited significantly higher apoptotic rate at 2-cell stage (8.3% versus 2.1%, P<0.05), 16-cell stage (27.3% versus 19.2%, P<0.05) and morula (37.5% versus 26.9, P<0.05) compared with IVF embryos. Compared with IVF embryos, a higher Bcl-2 mRNA expression pattern was observed in SCNT embryos before the 8-cell stage and differed significantly at 2-and 4-cell stages (P<0.05). After the 16-stage, Bcl-2 mRNA expression pattern became significantly lower in SCNT group (P <0.05). The relative expression level of Dnmt1 mRNA showed a higher expression level in oocytes, then sharply decreased and started to increase slightly after the 8-cell (IVF embryos) or 16-cell stage (SCNT embryos). Dnmt1 mRNA expression in IVF embryos appeared to have been lower than that of SCNT group before 16-cell stage embryos, especially at 4-and 8-cell stages (P<0.05). Although a trend for a similar increase of Dnmt3a expression was observed in IVF and SCNT embryos after 8-cell embryos, SCNT group resulted in much higher Dnmt3a mRNA abundance compared with the IVF group, particularly after 16-cell embryos (P<0.05).Conclusions The results showed that low efficiency of porcine SCNT technology may be associated with either embryonic apoptosis or incomplete reprogramming of donor nuclear caused by abnormal Dnmts mRNA expression.

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“…Earlier studies have revealed species-dependent expression patterns of DNA methyltransferases (DNMTs) genes in mammalian oocytes and preimplantation embryos (Vassena et al 2005), and also an association between incomplete DNA methylation and the lack of NT success in mammals (Dean et al 2001;Bortvin et al 2003;Chung et al 2003). Severely reduced transcript levels of DNMT1 have been reported in cloned than in IVF or parthenote bovine embryos by Golding et al (2011).…”

Section: Discussionmentioning

confidence: 99%

Differential developmental competence and gene expression patterns in buffalo (Bubalus bubalis) nuclear transfer embryos reconstructed with fetal fibroblasts and amnion mesenchymal stem cells

Shah

Yadav

2015

Cytotechnology

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The developmental ability and gene expression pattern at 8-to 16-cell and blastocyst stages of buffalo (Bubalus bubalis) nuclear transfer (NT) embryos from fetal fibroblasts (FFs), amnion mesenchymal stem cells (AMSCs) and in vitro fertilized (IVF) embryos were compared in the present studies. The in vitro expanded buffalo FFs showed a typical ''S'' shape growth curve with a doubling time of 41.4 h and stained positive for vimentin. The in vitro cultured undifferentiated AMSCs showed a doubling time of 39.5 h and stained positive for alkaline phosphatase, and these cells also showed expression of pluripotency markers (OCT4, SOX2, NANOG), and mesenchymal stem cell markers (CD29, CD44) and were negative for haematopoietic marker (CD34) genes at different passages. Further, when AMSCs were exposed to corresponding induction conditions, these cells differentiated into adipogenic, chondrogenic and osteogenic lineages which were confirmed through oil red O, alcian blue and alizarin staining, respectively. Donor cells at 3-4 passage were employed for NT. The cleavage rate was significantly (P \ 0.05) higher in IVF than in FF-NT and AMSC-NT embryos (82.6 ± 8.2 vs. 64.6 ± 1.3 and 72.3 ± 2.2 %, respectively). However, blastocyst rates in IVF and AMSC-NT embryos (30.6 ± 2.7 and 28.9 ± 3.1 %) did not differ and were significantly (P \ 0.05) higher than FF-NT (19.5 ± 1.8 %). Total cell number did not show significant (P [ 0.05) differences between IVF and AMSC-NT embryos (186.7 ± 4.2, 171.2 ± 3.8, respectively) but were significantly (P \ 0.05) higher than that from FF-NT (151.3 ± 4.1). Alterations in the expression pattern of genes implicated in transcription and pluripotency (OCT4, STAT3, NANOG), DNA methylation (DNMT1, DNMT3A), histone deacetylation (HDAC2), growth factor signaling and imprinting (IGF2, IGF2R), apoptosis (BAX, BCL2), metabolism (GLUT1) and oxidative stress (MnSOD) regulation were observed in cloned embryos. The transcripts or expression patterns in AMSC-NT embryos more closely followed that of the in vitro derived embryos compared with FF-NT embryos. The results demonstrate that multipotent amnion MSCs have a greater potential as donor cells than FFs in achieving enhanced production of cloned buffalo embryos.

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Abnormal Regulation of DNA Methyltransferase Expression in Cloned Mouse Embryos1

Cited by 139 publications

References 27 publications

Comparison of the RNA Polymerase I-, II- and III-Dependent Transcript Levels Between Nuclear Transfer and In Vitro Fertilized Embryos at the Blastocyst Stage

Comparison of the RNA Polymerase I-, II- and III-Dependent Transcript Levels Between Nuclear Transfer and In Vitro Fertilized Embryos at the Blastocyst Stage

Analysis of apoptosis and methyltransferase mRNA expression in porcine cloned embryos cultured in vitro

Differential developmental competence and gene expression patterns in buffalo (Bubalus bubalis) nuclear transfer embryos reconstructed with fetal fibroblasts and amnion mesenchymal stem cells

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