scholarly journals Technical, biological and molecular aspects of somatic cell nuclear transfer – a review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Patrycja Mrowiec ◽  
Monika Bugno-Poniewierska
Keyword(s):  
Somatic Cell ◽  
Nuclear Transfer ◽  
Basic Research ◽  
Genetically Engineered ◽  
Farm Animals ◽  
Fetal Mortality ◽  
Animal Cloning ◽  
Donor Nucleus ◽  
Molecular Aspects ◽  
Nuclear Remodeling

Abstract Since the announcement of the birth of the first cloned mammal in 1997, Dolly the Sheep, 24 animal species including laboratory, farm, and wild animals have been cloned. The technique for somatic cloning involves transfer of the donor nucleus of a somatic cell into an enucleated oocyte at the metaphase II (MII) stage for the generation of a new individual, genetically identical to the somatic cell donor. There is increasing interest in animal cloning for different purposes such as rescue of endangered animals, replication of superior farm animals, production of genetically engineered animals, creation of biomedical models, and basic research. However, the efficiency of cloning remains relatively low. High abortion, embryonic, and fetal mortality rates are frequently observed. Moreover, aberrant developmental patterns during or after birth are reported. Researchers attribute these abnormal phenotypes mainly to incomplete nuclear remodeling, resulting in incomplete reprogramming. Nevertheless, multiple factors influence the success of each step of the somatic cloning process. Various strategies have been used to improve the efficiency of nuclear transfer and most of the phenotypically normal born clones can survive, grow, and reproduce. This paper will present some technical, biological, and molecular aspects of somatic cloning, along with remarkable achievements and current improvements.

scholarly journals Generation of Genetically Engineered Livestock Using Somatic Cell Nuclear Transfer

Reproduction ◽  
2021 ◽  
Author(s):  
Irina Polejaeva
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Genetic Manipulation ◽  
Embryonic Stem ◽  
Genetically Engineered ◽  
Farm Animals ◽  
Technological Advancement ◽  
Genetic Mosaicism ◽  
Low Efficiency

Genetic engineering (GE) of livestock initially has been accomplished primarily using pronuclear microinjection into zygotes (1985 – 1996). The applications of technology were limited due to low integration efficiency, aberrant transgene expression resulting from random integration and presence of genetic mosaicism in transgenic founder animals. Despite enormous efforts to established embryonic stem cells (ESCs) for domestic species, the ESC GE technology does not exist for livestock. Development of Somatic Cell Nuclear Transfer (SCNT) has bypassed the need in livestock ESCs and revolutionized the field of livestock transgenesis by offering the first cell-based platform for precise genetic manipulation in farm animals. For nearly two decades since the birth of Dolly (1996 – 2013), SCNT was the only method used for generation of knockout and knockin livestock. Arrival of CRISPRS/Cas9 system, a new generation of gene editing technology, gave us an ability to introduce precise genome modifications easily and efficiently. This technological advancement accelerated production of GE livestock by SCNT and reinstated zygote micromanipulation as an important GE approach. The primary advantage of the SCNT technology is the ability to confirm in vitro that the desired genetic modification is present in the somatic cells prior to animal production. The edited cells could also be tested for potential off-target mutations. Additionally, this method eliminates the risk of genetic mosaicism frequently observed following zygote micromanipulation. Despite its low efficiency, SCNT is a well-established procedure in numerous laboratories around the world and will continue to play an important role in the GE livestock field.

Effects of ovary storage temperature and embryo vitrification on somatic cell nuclear transfer outcomes in goats

2020 ◽  
Vol 32 (4) ◽  
pp. 419 ◽  
Author(s):  
Mehdi Hajian ◽  
Farnoosh Jafarpour ◽  
Sayed Morteza Aghamiri ◽  
Shiva Rouhollahi Varnosfaderani ◽  
Mohammad Hossein Nasr Esfahani
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Storage Temperature ◽  
Storage Conditions ◽  
Farm Animals ◽  
Blastocyst Formation ◽  
Term Pregnancy ◽  
Developmental Potential ◽  
Genetic Potential

Improving the genetic potential of farm animals is one of the primary aims in the field of assisted reproduction. In this regard, somatic cell nuclear transfer (SCNT) can be used to produce a large number of embryos from genetically elite animals. The aims of the present study were to assess the effects of: (1) ovary storage conditions on preimplantation development of recovered oocytes and the freezability of the derived blastocysts; and (2) vitrification of goat SCNT-derived blastocysts on postimplantation development. Goat oocytes were recovered from ovaries and stored under warm (25°C-27°C) or cold (11°C-12°C) conditions before being used to produce SCNT embryos. There were no differences in oocytes recovered from ovaries kept under cold versus warm storage conditions in terms of cleavage (mean (±s.d.) 95.68±1.67% vs 95.91±2.93% respectively) and blastocyst formation (10.69±1.17% vs 10.94±0.9% respectively) rates. The re-expansion rate of vitrified blastocysts was significantly lower for cold- than warm-stored ovaries (66.3±8.7% vs 90±11% respectively). To assess the effects of vitrification on postimplantation development, blastocysts from cold-stored ovaries only were transferred from fresh and vitrified–warmed groups. The pregnancy rate was comparable between the fresh and vitrified–warmed groups (41.65% and 45.45% respectively). In addition, established pregnancy in Day 28-38 and full-term pregnancy rates were similar between the two groups. In conclusion, this study shows similar invitro preimplantation developmental potential of warm- and cold-stored ovaries. This study introduces the vitrification technique as an appropriate approach to preserve embryos produced by SCNT for transfer to recipient goats at a suitable time.

scholarly journals Microtubule distribution in somatic cell nuclear transfer bovine embryos following control of nuclear remodeling type

2010 ◽  
Vol 11 (2) ◽  
pp. 93 ◽  
Author(s):  
Dae-Jin Kwon ◽  
Yu-Mi Lee ◽  
In-Sun Hwang ◽  
Choon-Keun Park ◽  
Boo-Keun Yang ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Bovine Embryos ◽  
Nuclear Remodeling

scholarly journals Insights on bovine genetic engineering and cloning

2013 ◽  
Vol 33 (suppl 1) ◽  
pp. 113-118 ◽  
Author(s):  
Fabiana F. Bressan ◽  
Juliano R. Sangalli ◽  
Laís V.F. Pessôa ◽  
Pedro R.L. Pires ◽  
Flávio V. Meirelles
Keyword(s):  
Genetic Engineering ◽  
Somatic Cell ◽  
Genetic Modification ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Gene Induction ◽  
Transgenic Technology ◽  
Animal Cloning ◽  
Cell Lineages ◽  
Genetically Modified Animals

Transgenic technology has become an essential tool for the development of animal biotechnologies, and animal cloning through somatic cell nuclear transfer (SCNT) enabled the generation of genetically modified animals utilizing previously modified and selected cell lineages as nuclei donors, assuring therefore the generation of homogeneous herds expressing the desired modification. The present study aimed to discuss the use of SCNT as an important methodology for the production of transgenic herds, and also some recent insights on genetic modification of nuclei donors and possible effects of gene induction of pluripotency on SCNT.

Somatic cell nuclear transfer in pigs: recent achievements and future possibilities

2007 ◽  
Vol 19 (2) ◽  
pp. 403 ◽  
Author(s):  
Gábor Vajta ◽  
Yunhai Zhang ◽  
Zoltán Macháty
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Direct Evidence ◽  
Research Area ◽  
Genetically Engineered ◽  
Transgenic Pigs ◽  
Actual Performance ◽  
Donor Cells

During the past 6 years, considerable advancement has been achieved in experimental embryology of pigs. This process was mainly generated by the rapidly increasing need for transgenic pigs for biomedical research purposes, both for future xenotransplantation to replace damaged human organs or tissues, and for creating authentic animal models for human diseases to study aetiology, pathogenesis and possible therapy. Theoretically, among various possibilities, an established somatic cell nuclear transfer system with genetically engineered donor cells seems to be an efficient and reliable approach to achieve this goal. However, as the result of unfortunate coincidence of known and unknown factors, porcine embryology had been a handicapped branch of reproductive research in domestic animals and a very intensive and focused research was required to eliminate or minimise this handicap. This review summarises recent achievements both in the background technologies (maturation, activation, embryo culture) and the actual performance of the nuclear replacement. Recent simplified methods for in vivo development after embryo transfer are also discussed. Finally, several fields of potential application for human medical purposes are discussed. The authors conclude that although in this early phase of research no direct evidence can be provided about the practical use of transgenic pigs produced by somatic cell nuclear transfer as organ donors or disease models, the future chances even in medium term are good, and at least proportional with the efforts and sums that are invested into this research area worldwide.

Nuclear Remodeling in Bovine Somatic Cell Nuclear Transfer Embryos Using MG132-Treated Recipient Oocytes

2010 ◽  
Vol 12 (6) ◽  
pp. 729-738 ◽  
Author(s):  
Daniel Le Bourhis ◽  
Nathalie Beaujean ◽  
Sylvie Ruffini ◽  
Xavier Vignon ◽  
Laurence Gall
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Nuclear Remodeling

Transgenesis in farm animals-A review

2017 ◽  
Vol 38 (02) ◽  
Author(s):  
Parul Mehta ◽  
Ankur Sharma ◽  
Ramakant Kaushik
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Transgenic Animals ◽  
Farm Animals ◽  
Zinc Finger Nucleases ◽  
The Novel ◽  
Transcription Activator ◽  
Human Welfare ◽  
Transgenic Livestock

For a number of decades, attempts have been made to successfully produce transgenic animals which have numerous applications in the biotechnology industry with the foremost emphasis on production of monoclonal antibodies and recombinant proteins of human welfare. Different techniques are adopted in order to produce transgenic farm animals which could be further used as bioreactors. The most common traditional transgenesis technique employed is Somatic Cell Nuclear Transfer (SCNT) using genetically modified somatic cells or stem cells as nuclear donors. This review article summarizes the merits and demerits of the techniques currently used to produce transgenic livestock with major emphasis on somatic cell nuclear transfer. In the end, a brief discussion is done about the novel methods adopted to produce transgenic animals like Zinc Finger Nucleases (ZFN), Transcription Activator-like Effector Nuclease (TALEN) and Clustered regularly interspaced short palindromic repeats (CRISPR). It is expected that the new techniques developed would overcome the problems faced with existing traditional transgenesis methods.

scholarly journals Reprogramming following somatic cell nuclear transfer in primates is dependent upon nuclear remodeling

2007 ◽  
Vol 22 (8) ◽  
pp. 2232-2242 ◽  
Author(s):  
S.M. Mitalipov ◽  
Q. Zhou ◽  
J.A. Byrne ◽  
W.Z. Ji ◽  
R.B. Norgren ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Somatic Cell Nuclear Transfer ◽  
Nuclear Transfer ◽  
Nuclear Remodeling
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