Recent advancements in cloning by somatic cell nuclear transfer

Ogura, Atsuo; Inoue, Kimiko; Wakayama, Teruhiko

doi:10.1098/rstb.2011.0329

Cited by 187 publications

(184 citation statements)

References 143 publications

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“…Compared to fertilized embryos, cloned embryos display higher levels of DNA methylation and incomplete chromatin remodeling (Zhang et al 2009, Mason et al 2012, Rodriguez-Osorio et al 2012. To improve NT efficiency, several approaches, including the use of chemical inhibitors such as HDAC inhibitors (HDACi) and 5-aza-C, have been devised to facilitate the reprogramming of somatic nuclei and establish embryonic epigenetic patterns (Ogura et al 2013). HDACi treatment for altering the epigenetic status of donor cells or cloned embryos can significantly increase cloning efficiency.…”

Section: Introductionmentioning

confidence: 99%

Dnmt3l-knockout donor cells improve somatic cell nuclear transfer reprogramming efficiency

Liao¹,

Mo²,

Wu³

et al. 2015

Reproduction

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Nuclear transfer (NT) is a technique used to investigate the development and reprogramming potential of a single cell. DNA methyltransferase-3-like, which has been characterized as a repressive transcriptional regulator, is expressed in naturally fertilized egg and morula/blastocyst at pre-implantation stages. In this study, we demonstrate that the use of Dnmt3l-knockout (Dnmt3l-KO) donor cells in combination with Trichostatin A treatment improved the developmental efficiency and quality of the cloned embryos. Compared with the WT group, Dnmt3l-KO donor cell-derived cloned embryos exhibited increased cell numbers as well as restricted OCT4 expression in the inner cell mass (ICM) and silencing of transposable elements at the blastocyst stage. In addition, our results indicate that zygotic Dnmt3l is dispensable for cloned embryo development at pre-implantation stages. In Dnmt3l-KO mouse embryonic fibroblasts, we observed reduced nuclear localization of HDAC1, increased levels of the active histone mark H3K27ac and decreased accumulation of the repressive histone marks H3K27me3 and H3K9me3, suggesting that Dnmt3l-KO donor cells may offer a more permissive epigenetic state that is beneficial for NT reprogramming. Reproduction (2015) 150 245-256

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Section: Introductionmentioning

confidence: 99%

Dnmt3l-knockout donor cells improve somatic cell nuclear transfer reprogramming efficiency

Liao¹,

Mo²,

Wu³

et al. 2015

Reproduction

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“…First, the oocytes were enucleated in the presence of caffeine and second, after NT the reconstructed embryos were cultured in a medium containing TSA (trichostatin A). In fact, both these treatments were already used in animal NT experiments and improved their efficiency [9]. In general, the NT scheme has been perfected in previous experiments performed by this group and some other technical details can be found in a given paper [5].…”

Section: Inconsistent Resultsmentioning

confidence: 99%

“…Instead, it is commonly accepted that the oocyte cytoplasmic milieu is the most direct means to obtaining reprogramming of a differentiated somatic cell nucleus [9,10]. This fact-the quality of the oocyte cytoplasmic milieu-may well underscore the reason that while research on human SCNT continues, reports are rare in this species relative to the many papers published in other mammals.…”

mentioning

confidence: 99%

The ups and downs of somatic cell nucleus transfer (SCNT) in humans

Fulka

Langerova

Loi

et al. 2013

J Assist Reprod Genet

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Achieving successful somatic cell nuclear transfer (SCNT) in the human and subhuman primate relative to other mammals has been questioned for a variety of technical and logistical issues. Here we summarize the gradual evolution of SCNT technology from the perspective of oocyte quality and cell cycle status that has recently led to the demonstration of feasibility in the human for deriving chromosomally normal stem cells lines. With these advances in hand, prospects for therapeutic cloning must be entertained in a conscientious, rigorous, and timely fashion before broad spectrum clinical applications are undertaken.Keywords Nucleus . Oocyte . Nucleus transfer Simply stated, SCNT in mammals should in practice be a very straightforward technique. First, cytoplasts are prepared by enucleating the metaphase II stage oocytes, i.e. metaphase II chromosomes are removed from the oocyte. Second, the selected nucleus is introduced into the cytoplast either by direct injection or by induced cell fusion. The reconstructed SCNT products are then activated in ways mimicking fertilization and if everything goes well cloned embryos develop [6].Logically, since following the birth of Dolly [7], and the production of additional clones in other mammalian species, there is ample confirmation that Dolly was not an exceptional case, prompting widespread discussion regarding the pros and cons of human SCNT. Given this prospect, it has been commonly accepted and broadly emphasized that the production of cloned human individuals must be banned (reproductive cloning). On the other hand, the production of embryos from which patient compatible embryonic stem cells could be obtained seemed to be acceptable, at least in some countries (therapeutic cloning). However, once the discovery of induced pluripotent stem cell production (iPSC) was realized by the work of Takahashi and Yamanaka [see 8 for review], illustrating that differentiated or even terminally differentiated cells can be converted (dedifferentiated) into a pluripotent state by induced overexpression of four factors (Oct 4, Sox 2, Klf 4, c-Myc; OSKM), greater resistance against the use of SCNT in humans has emerged, including the prospect of therapeutic cloning.Although many papers on modifications of the original iPS technology seeking improved efficiency and safety have been published, it should be emphasized that our understanding of the mechanisms by which iPSC elicits dedifferentiation remain woefully incomplete. Instead, it is commonly accepted that the oocyte cytoplasmic milieu is the most direct means to obtaining reprogramming of a differentiated somatic cell nucleus [9,10]. This fact-the quality of the oocyte cytoplasmic milieu-may well underscore the reason that while research on human SCNT continues, reports are rare in this species relative to the many papers published in other mammals. Birth of DollyThe work that led to the birth of Dolly was antedated by many years of experiments using laboratory and domestic animals to test many methodological combinations ...

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“…Accumulated evidence suggests that HDACis are highly important to aid nuclear reprogramming with a consequent increase in SCNT efficiency in mice (OGURA et al, 2013). This improvement, in swine, was recently awarded in the HDACis`s ability on DNA damage repair mechanism.…”

Section: Epigenetic Mechanisms Of Natural Reprogramming Versus Cloningmentioning

confidence: 99%

Challenges and perspectives to enhance cattle production via in vitro techniques: focus on epigenetics and cell-secreted vesicles

et al. 2015

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Recent advancements in cloning by somatic cell nuclear transfer

Cited by 187 publications

References 143 publications

Dnmt3l-knockout donor cells improve somatic cell nuclear transfer reprogramming efficiency

Dnmt3l-knockout donor cells improve somatic cell nuclear transfer reprogramming efficiency

The ups and downs of somatic cell nucleus transfer (SCNT) in humans

Challenges and perspectives to enhance cattle production via in vitro techniques: focus on epigenetics and cell-secreted vesicles

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