The analysis of telomere length and telomerase activity in cloned pigs and cows

Jeon, Hyun Yong; Hyun, Sang‐Hwan; Lee, G.S.; Kim, H.S.; Kim, S.; Jeong, Yeon Woo; Kang, Sung Keun; Lee, B.C.; Han, Jae Yong; Ahn, Curie; Hwang, Wontae

doi:10.1002/mrd.20279

Cited by 60 publications

(37 citation statements)

References 28 publications

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“…Although porcine embryos from somatic cell nuclear transfer acquire a typical methylation pattern as control embryos and have normal telomere length (Jeon et al 2005;Kang et al 2001b), they display sporatic dysregulation of genes that are critical to embryo development (Lee et al 2004;Miyazaki et al 2005). This is consistent with the widely reported abnormal gene expression in mouse and bovine NT embryos (Bortvin et al 2003;Daniels et al 2000;Han et al 2003;Mann et al 2003;Wrenzycki et al 2002;Wrenzycki et al 2001).…”

Section: Discussionmentioning

confidence: 62%

Expression of X‐linked genes in deceased neonates and surviving cloned female piglets

Jiang

Lai

Samuel

et al. 2007

Molecular Reproduction Devel

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Animal cloning through somatic cell nuclear transfer is very inefficient, probably due to insufficient reprogramming of the donor nuclei, which in turn would cause the dysregulation of gene expression. X-Chromosome inactivation (XCI) is a multi-step epigenetic process utilized by mammals to achieve dosage compensation in females. Our aim was to determine if any dysregulation of X-linked genes, which would be indicative of unfaithful reprogramming of donor nuclei, was present in cloned pigs. Real time reverse transcription polymerase chain reaction (RT-PCR) was performed to quantify the transcript levels of five X-linked genes, XIST, TSIX, HPRT1, G6PD, ARAF1 and one autosomal gene, COL4A1 in major organs of neonatal deceased and surviving female cloned pigs and age-matched control pigs from conventional breeding. Aberrant expression level of these genes was prevalent in the neonatal deceased clones, while it was only moderate in cloned pigs that survived after birth. These results suggest a correlation between the viability of the clones and the normality of their gene expression and provide a possible explanation for the death of a large portion of cloned animals around birth.

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Section: Discussionmentioning

confidence: 62%

Expression of X‐linked genes in deceased neonates and surviving cloned female piglets

Jiang

Lai

Samuel

et al. 2007

Molecular Reproduction Devel

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“…We found relatively high levels of telomerase expression in both in vivo and in vitro-produced blastocysts. Relatively high levels of telomerase activity were previously described in porcine and bovine blastocysts derived in vitro and in vivo [36][37][38]. The samples used for telomerase expression assessment in our blastocyst-derived cell lines were collected during culture passaging.…”

Section: Discussionmentioning

confidence: 99%

Analysis of Marker Expression in Porcine Cell Lines Derived from Blastocysts Produced In Vitro and In Vivo

et al. 2011

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Abstract. The present study was designed to extensively characterize cell lines derived from porcine blastocysts by several methodical approaches, including morphological observation, cytogenetic analysis, estimation of alkaline phosphatase activity and detection of specific marker expression at the mRNA/protein level. A comparison was made between the properties of cell lines isolated from in vivo-and in vitro-obtained blastocysts. Our results showed that 57.1% of the in vivo-obtained blastocysts attached to the feeder layer and that 33.3% of them started to grow in a monolayer. The percentage of attached in vitro-produced blastocysts was lower (24.6%), and only 6.9% of them started to grow. Outgrowths from the in vitro-produced blastocysts formed mainly trophectoderm or epithelial-like monolayer, whereas the in vivo-obtained blastocysts formed heterogeneous outgrowths that also contained cells with embryonic stem (ES)-like morphology. Detailed analyses showed that the primary outgrowths with ES-like morphology expressed the pluripotency markers OCT-4 and NANOG and revealed intensive alkaline phosphatase staining, while they did not express markers of differentiation. The majority of passaged cells, including those with ESlike morphology, lacked OCT-4 protein and revealed expression of specific differentiation markers (CYTOKERATIN 18, LAMINS A/C, TRANSFERRIN, α-FETOPROTEIN and GATA-4), although they still expressed NANOG and exhibited weak alkaline phosphatase activity. Moreover, these cells spontaneously differentiated into neural, fibroblast or epithelial-like cells, even in the presence of leukaemia inhibitory factor. Our results show that complex analysis of markers of pluripotency as well as differentiation markers is necessary for proper interpretation of data in porcine embryonic stem cell studies. Key words: Blastocyst, In vitro, In vivo, Pig, Stem cells (J. Reprod. Dev. 57: [594][595][596][597][598][599][600][601][602][603] 2011) he successful isolation and characterization of mouse ES (embryonic stem) cell lines [1,2] has resulted in considerable efforts aimed to establish ES cell lines in other species, including humans. ES cells are unique cells with the capacity for unlimited proliferation without differentiation under optimal in vitro conditions and with broad differentiation plasticity in vivo and in vitro. When introduced into blastocysts, they can contribute to all cell lineages, including the germline [3]. Validated ES cells with all of these properties have been isolated only in the mouse and rat [4], as no germline chimeras have been reported in other mammals. The absence of cell lines capable of generating germline chimeras limits the possibility of using farm animal ES cells as tools for genetic manipulation [5]. Since 1998, when pluripotent human ES cell lines were established [6], ES cell research has been mainly focused on therapeutic use in human medicine. Before stem cell therapies are introduced into human medicine, it will be necessary to develop and verify the safety and effecti...

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“…Subsequently, however, the vast majority of cloning studies reported that telomere length in cloned cattle, pigs, goats and mice are comparable with age-matched, naturally bred controls even when senescent donor cells were used for cloning (Jiang et al 2004, Betts et al 2005, Jeon et al 2005, Schaetzlein & Rudolph 2005. The regulation of telomere length is to some extent related to the type of donor cells employed for cloning.…”

Section: Telomere Length and Somatic Cloningmentioning

confidence: 99%

Epigenetic reprogramming in embryonic and foetal development upon somatic cell nuclear transfer cloning

Niemann¹,

Tian²,

King³

et al. 2008

Reproduction

196

116

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The birth of 'Dolly', the first mammal cloned from an adult donor cell, has sparked a flurry of research activities to improve cloning technology and to understand the underlying mechanism of epigenetic reprogramming of the transferred somatic cell nucleus. Especially in ruminants, somatic cell nuclear transfer (SCNT) is frequently associated with pathological changes in the foetal and placental phenotype and has significant consequences for development both before and after birth. The most critical factor is epigenetic reprogramming of the transferred somatic cell nucleus from its differentiated status into the totipotent state of the early embryo. This involves an erasure of the gene expression program of the respective donor cell and the establishment of the well-orchestrated sequence of expression of an estimated number of 10 000-12 000 genes regulating embryonic and foetal development. The following article reviews the present knowledge on the epigenetic reprogramming of the transferred somatic cell nucleus, with emphasis on DNA methylation, imprinting, X-chromosome inactivation and telomere length restoration in bovine development. Additionally, we briefly discuss other approaches towards epigenetic nuclear reprogramming, including the fusion of somatic and embryonic stem cells and the overexpression of genes crucial in the formation and maintenance of the pluripotent status. Improvements in our understanding of this dramatic epigenetic reprogramming event will be instrumental in realising the great potential of SCNT for basic biological research and for various agricultural and biomedical applications.

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The analysis of telomere length and telomerase activity in cloned pigs and cows

Cited by 60 publications

References 28 publications

Expression of X‐linked genes in deceased neonates and surviving cloned female piglets

Expression of X‐linked genes in deceased neonates and surviving cloned female piglets

Analysis of Marker Expression in Porcine Cell Lines Derived from Blastocysts Produced In Vitro and In Vivo

Epigenetic reprogramming in embryonic and foetal development upon somatic cell nuclear transfer cloning

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