328 NONVIRAL REPROGRAMMING OF mCHERRY-EXPRESSING PORCINE FIBROBLASTS INTO INDUCED PLURIPOTENT STEM CELLS BY piggyBac TRANSPOSONS

2015 ◽  
Vol 27 (1) ◽  
pp. 253
Author(s):  
D. Kumar ◽  
T. R. Talluri ◽  
W. A. Kues
Keyword(s):  
Stem Cells ◽  
Ips Cells ◽  
Large Animal ◽  
Suitable Model ◽  
Differentiation Potential ◽  
Piggybac Transposon ◽  
Increased Risk ◽  
Fetal Fibroblasts ◽  
Induced Pluripotent

The generation of induced pluripotent stem (iPS) cells is a promising approach for innovative cell therapies, as well as for animal biotechnology. The original method requires viral transduction of several reprogramming factors, which may be associated with an increased risk of tumorigenicity due to the preferential integration into active genes. The domestic pig is an attractive large animal model for preclinical testing of safety and efficacy of cell-based therapies. Porcine organs are similar in size and physiology to their human counterparts, and a suitable model for cardiovascular disease, muscular dystrophies, atherosclerosis, wound repair, diabetes, and ophthalmological diseases. Therefore, the present study was carried out to derive porcine iPS cells from transgenic fetuses systemically expressing mCherry (Garrels et al. 2011 PLOS ONE 6) through a nonviral piggyBac transposon. The piggyBac transposon system has several advantages: (i) piggyBac has no bias to integrate in expressed gene-like lenti- or retroviral vectors, (ii) the cargo capacity is >100 kb, (iii) seamless removal is possible, and (iv) the production of transposon plasmid is cost-efficient and does not require S2 safety cabinets. Porcine fetal fibroblasts isolated from CAGGS-mCherry founder porcine line fetuses (passage 2), were co-electroporated with a PB transposon carrying a multigene cassette consisting of human cDNA for OCT4, SOX2, KLF4, c-MYc, NANOG, and LIN28 separated by self-cleaving 2A peptide sequences, driven by a CAGGS promoter and a helper plasmid expressing the pCMV-PB transposase. On Day 6 postelectroporation, morphology of fibroblasts started change to round structure, and on Day 9 loose aggregates of cells developed. Putative iPS cell colonies were cultured, propagated, and characterised through morphology and expression of pluripotency markers, such as AP, OCT4, SSEA-1, and SSEA-4, through immunostaining. Further, various stemness genes, including OCT4, SOX2, NANOG, and UTF, were detected by porcine-specific primers through endpoint RT-PCR. In vitro differentiation potential was assessed by embryoid body (EB) formation. The formed EB exhibited the expression of mCherry in their cells and expressed differentiation markers, such as NESTIN, TUJI, GATA4 and AFP. To test their tumorigenic potential, 1 × 106 iPS cells were injected under the skin of nude mice. An mCherry-positive tumour was recovered 6 weeks later. Presently the tumour is being prepared for histological analysis. This study indicates that piggyBac transposon containing 6 transcription factors is able to reprogram porcine fetal fibroblasts into iPS cells. These cells could be cultured and maintained in vitro for a prolonged period, exhibit characteristics of stem cells, and offer a potential source for future blastocyst complementation experiments.

206 GENERATION OF HUMAN INDUCED PLURIPOTENT STEM CELLS FROM DENTAL PULP-DERIVED MESENCHYMAL STEM CELLS

2012 ◽  
Vol 24 (1) ◽  
pp. 215 ◽  
Author(s):  
J. H. Lee ◽  
Y. M. Lee ◽  
G. H. Maeng ◽  
R. H. Jeon ◽  
T. H. Kim ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dental Pulp ◽  
Ips Cells ◽  
Retroviral Vector ◽  
Transcriptional Factors ◽  
Alizarin Red ◽  
Differentiation Potential ◽  
Induced Pluripotent ◽  
Oil Red O

Induced pluripotent stem (iPS) cells are somatic cells that have been reprogrammed to a pluripotent state and a great source for regenerative medicine. Several types of human somatic and adult stem cells have been reprogrammed into iPS cells, including mesenchymal stem cells (MSC). Recently, human dental pulp has been considered as a valuable alternative source of MSC (hDP-MSC) with excellent proliferation capacity and multilineage differentiation potential. In this study, our objective was to establish iPS cells from hDP-MSC and evaluate the expression of transcriptional factors and in vitro differentiation potential into mesenchymal lineages. The hMSC were isolated from the dental pulp of male donor (∼18 years old) were cultured in advanced-DMEM supplemented with 10% fetal bovine serum at 37°C, 5% CO2 in a humidified atmosphere. The hDP-MSC at passage 3 were analysed for the expression of MSC-specific surface markers (CD44 and CD90) using flow cytometry and transcriptional factors (Oct4, Nanog and Sox2) by immunofluorescence staining and reverse transcription-polymerase chain reaction (RT-PCR). Differentiation into adipocytes and osteocytes of hDP-MSC was carried out under specific conditions for 2 and 4 weeks, respectively and assessed by cytochemical staining (Oil red O, von Kossa and Alizarin Red S, respectively). iPS cells were generated from hDP-MSC at passage 3 by using pMXs retroviral vector (Addgene, Cambridge, MA, USA) containing cDNA of c-Myc, Klf4, Nanog and Sox2. The iPS cells were evaluated for alkaline phosphatase (AP) activity, expression of human embryonic stem cells (hESC) markers (Rex1, Nanog, Oct4, SSEA-1 and TRA-160) by immunostaining. Isolated hDP-MSC expressed surface markers, such as CD44 and CD90 (86% and 93%, respectively) by flow cytometry and positively stained for transcriptional factors (Oct4, Nanog and Sox2) by immunofluorescence. Further, the cells were capable of differentiating in vitro into adipocytes and osteocytes as demonstrated by Oil red O and von Kossa and Alizarin red S staining, respectively. The iPS cells generated from hDP-MSC were positive for AP staining and clearly expressed the markers specific to hESC, including Rex1, Nanog, Oct4, SSEA-1 and TRA-160. In conclusion, hMSC derived from dental pulp could be successfully reprogrammed into iPS cells by retroviral vector systems and the generated iPS cells shared the similar characteristics of hESC. Therefore, hDP-MSC might be an ideal alternative cell source to derive autologous iPS cells for therapeutic applications. This work was supported by Grant No. 2007031034040 from Bio-organ and Grant No. 200908FHT010204005 from Biogreen21.

Mini Review; Differentiation of Human Pluripotent Stem Cells into Oocytes

2020 ◽  
Vol 15 (4) ◽  
pp. 301-307 ◽  
Author(s):  
Gaifang Wang ◽  
Maryam Farzaneh
Keyword(s):  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Embryonic Stem ◽  
Human Pluripotent Stem Cells ◽  
Human Oocyte ◽  
Differentiation Potential ◽  
Cell Lineages ◽  
Cell Based Therapy ◽  
Induced Pluripotent

Primary Ovarian Insufficiency (POI) is one of the main diseases causing female infertility that occurs in about 1% of women between 30-40 years of age. There are few effective methods for the treatment of women with POI. In the past few years, stem cell-based therapy as one of the most highly investigated new therapies has emerged as a promising strategy for the treatment of POI. Human pluripotent stem cells (hPSCs) can self-renew indefinitely and differentiate into any type of cell. Human Embryonic Stem Cells (hESCs) as a type of pluripotent stem cells are the most powerful candidate for the treatment of POI. Human-induced Pluripotent Stem Cells (hiPSCs) are derived from adult somatic cells by the treatment with exogenous defined factors to create an embryonic-like pluripotent state. Both hiPSCs and hESCs can proliferate and give rise to ectodermal, mesodermal, endodermal, and germ cell lineages. After ovarian stimulation, the number of available oocytes is limited and the yield of total oocytes with high quality is low. Therefore, a robust and reproducible in-vitro culture system that supports the differentiation of human oocytes from PSCs is necessary. Very few studies have focused on the derivation of oocyte-like cells from hiPSCs and the details of hPSCs differentiation into oocytes have not been fully investigated. Therefore, in this review, we focus on the differentiation potential of hPSCs into human oocyte-like cells.

Abstract 340: From Stem Cells to Cardiomyocytes: HDAC1 Induces Cardiovascular Differentiation by Regulating SOX17-BMP2 Expression in Early Development.

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Eneda Hoxha ◽  
Erin Lambers ◽  
Veronica Ramirez ◽  
Prasanna Krishnamurthy ◽  
Suresh Verma ◽  
...  
Keyword(s):  
Stem Cells ◽  
Molecular Mechanisms ◽  
Es Cells ◽  
Ips Cells ◽  
Full Potential ◽  
Pluripotent Cells ◽  
Differentiation Potential ◽  
Histone Deacetylase 1 ◽  
Specific Differentiation ◽  
Induced Pluripotent

Cardiomyocytes derived from embryonic and induced pluripotent stem cells (ES/iPS) provide an excellent source for cell replacement therapies following myocardial ischemia. However, some of the obstacles in the realization of the full potential of iPS/ES cells arise from incomplete and poorly understood molecular mechanisms and epigenetic modifications that govern their cardiovascular specific differentiation. We identified Histone Deacetylase 1 (HDAC1) as a crucial regulator in early differentiation of mES and iPS cells. We propose a novel pathway in which HDAC1 regulates cardiovascular differentiation by regulating SOX17 which in turn regulates BMP2 signaling in differentiating pluripotent cells. Utilizing stable HDAC1 knock-down (HDAC1-KD) cell lines, we report an essential role for HDAC1 in deacetylating regulatory regions of pluripotency-associated genes during early cardiovascular differentiation. HDAC1-KD cells show severely repressed cardiomyocyte differentiation potential. We propose a novel HDAC1-BMP2-SOX17 dependent pathway through which deacetylation of pluripotency associated genes leads to their suppression and allows for early cardiovascular-associated genes to be expressed and differentiation to occur. Furthermore, we show that HDAC1 affects DNA methylation both during pluripotency and differentiation and plays a crucial, non-redundant role in cardiovascular specific differentiation and cardiomyocyte maturation. Our data elucidates important differences between ES and iPS HDAC1-KD cells that affect their ability to differentiate into cardiovascular lineages. As varying levels of chromatin modifying enzymes are likely to exist in patient derived iPS cells, understanding the molecular circuitry of these enzymes in ES and iPS cells is critical for their potential therapeutic applications in regenerative medicine. Further research in the molecular mechanisms involved in this process will greatly aid our understanding of the epigenetic circuitry of pluripotency and differentiation in pluripotent cells.

1 GENERATION OF A STABLE TRANSGENIC SWINE MODEL FOR CELL TRACKING AND CHROMOSOME DYNAMIC STUDIES

2016 ◽  
Vol 28 (2) ◽  
pp. 130
Author(s):  
R. Sper ◽  
S. Simpson ◽  
X. Zhang ◽  
B. Collins ◽  
J. Piedrahita
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Animal Model ◽  
Regenerative Medicine ◽  
Cancer Biology ◽  
Large Animal Model ◽  
Large Animal ◽  
Fetal Fibroblasts ◽  
Transgene Transmission

Transgenic pigs are an attractive research model in the field of translational research, regenerative medicine, and stem cell therapy due to their anatomic, genetic, and physiological similarities with humans. The development of a transgenic murine model with a fusion of green fluorescent protein (GFP) to histone 2B protein (H2B, protein of nucleosome core) resulted in an easier and more convenient method for tracking cell migration and engraftment levels after transplantation as well as a way to better understand the complexity of molecular regulation within cell cycle/division, cancer biology, and chromosome dynamics. Up to now the development of a stable transgenic large animal model expressing H2B-GFP has not been described. Our objective was to develop the first transgenic porcine H2B-GFP model via CRISPR-CAS9 mediated recombination and somatic cell nuclear transfer (SCNT). Porcine fetal fibroblasts were cotransfected with CRISPR-CAS9 designed to target the 3′ untranslated region of ACTB locus and a targeting vector containing 1Kb homology arms to ACTB flanking an IRES-H2B-GFP transgene. Four days after transfection GFP cells were fluorescence activated cell sorted. Single cell colonies were generated and analysed by PCR, and heterozygous colonies were used as donor cells for SCNT. The custom designed CRISPR-CAS9 knockin system demonstrated a 2.4% knockin efficiency. From positive cells, 119 SCNT embryos were generated and transferred to a recipient gilt resulting in three positive founder boars (P1 generation). Boars show normal fertility (pregnancies obtained via AI of wild type sows). Generated P1 clones were viable and fertile with a transgene transmission rate of 55.8% (in concordance with Mendel’s law upon chi-square test with P = 0.05). Intranuclear H2B-GFP expression was confirmed via fluorescence microscopy on 8-day in vitro cultured SCNT blastocysts and a variety of tissues (heart, kidney, brain, bladder, skeletal muscle, stomach, skin, and so on) and primary cultured cells (chondrocytes, bone marrow derived, adipocyte derived, neural stem cells, and so on) from P1 cloned boars and F1 42-day fetuses and viable piglets. In addition, chromosome segregation could be easily identified during cell cycle division in in vitro cultured stem cells. Custom designed CRISPR-CAS 9 are able to drive homologous recombination in the ACTB locus in porcine fetal fibroblasts, allowing the generation of the first described viable H2B-GFP porcine model via SCNT. Generated clones and F1 generation expressed H2B-GFP ubiquitously, and transgene transmission rates were with concordance of Mendel’s law. This novel large animal model represents an improved platform for regenerative medicine and chromosome dynamic and cancer biology studies.

scholarly journals N-Acetylcysteine prevents amyloid-β secretion in neurons derived from human pluripotent stem cells with trisomy 21

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiromitsu Toshikawa ◽  
Akihiro Ikenaka ◽  
Li Li ◽  
Yoko Nishinaka-Arai ◽  
Akira Niwa ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Therapeutic Option ◽  
Amyloid Β ◽  
Chromosome 21 ◽  
Extra Copy ◽  
Increased Risk ◽  
Induced Pluripotent

AbstractDown syndrome (DS) is caused by the trisomy of chromosome 21. Among the many disabilities found in individuals with DS is an increased risk of early-onset Alzheimer's disease (AD). Although higher oxidative stress and an upregulation of amyloid β (Aβ) peptides from an extra copy of the APP gene are attributed to the AD susceptibility, the relationship between the two factors is unclear. To address this issue, we established an in vitro cellular model using neurons differentiated from DS patient-derived induced pluripotent stem cells (iPSCs) and isogenic euploid iPSCs. Neurons differentiated from DS patient-derived iPSCs secreted more Aβ compared to those differentiated from the euploid iPSCs. Treatment of the neurons with an antioxidant, N-acetylcysteine, significantly suppressed the Aβ secretion. These findings suggest that oxidative stress has an important role in controlling the Aβ level in neurons differentiated from DS patient-derived iPSCs and that N-acetylcysteine can be a potential therapeutic option to ameliorate the Aβ secretion.

scholarly journals Generation of male germ cells from induced pluripotent stem cells (iPS cells): an in vitro and in vivo study

2012 ◽  
Vol 14 (4) ◽  
pp. 574-579 ◽  
Author(s):  
Yong Zhu ◽  
Hong-Liang Hu ◽  
Peng Li ◽  
Shi Yang ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Germ Cells ◽  
Pluripotent Stem Cells ◽  
Ips Cells ◽  
In Vivo Study ◽  
Male Germ Cells ◽  
Induced Pluripotent

scholarly journals Exogenous LIN28 Is Required for the Maintenance of Self-Renewal and Pluripotency in Presumptive Porcine-Induced Pluripotent Stem Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Warunya Chakritbudsabong ◽  
Somjit Chaiwattanarungruengpaisan ◽  
Ladawan Sariya ◽  
Sirikron Pamonsupornvichit ◽  
Joao N. Ferreira ◽  
...  
Keyword(s):  
Stem Cells ◽  
Alkaline Phosphatase ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Embryoid Bodies ◽  
Self Renewal ◽  
Fetal Fibroblasts ◽  
Induced Pluripotent

Porcine species have been used in preclinical transplantation models for assessing the efficiency and safety of transplants before their application in human trials. Porcine-induced pluripotent stem cells (piPSCs) are traditionally established using four transcription factors (4TF): OCT4, SOX2, KLF4, and C-MYC. However, the inefficiencies in the reprogramming of piPSCs and the maintenance of their self-renewal and pluripotency remain challenges to be resolved. LIN28 was demonstrated to play a vital role in the induction of pluripotency in humans. To investigate whether this factor is similarly required by piPSCs, the effects of adding LIN28 to the 4TF induction method (5F approach) on the efficiency of piPSC reprogramming and maintenance of self-renewal and pluripotency were examined. Using a retroviral vector, porcine fetal fibroblasts were transfected with human OCT4, SOX2, KLF4, and C-MYC with or without LIN28. The colony morphology and chromosomal stability of these piPSC lines were examined and their pluripotency properties were characterized by investigating both their expression of pluripotency-associated genes and proteins and in vitro and in vivo differentiation capabilities. Alkaline phosphatase assay revealed the reprogramming efficiencies to be 0.33 and 0.17% for the 4TF and 5TF approaches, respectively, but the maintenance of self-renewal and pluripotency until passage 40 was 6.67 and 100%, respectively. Most of the 4TF-piPSC colonies were flat in shape, showed weak positivity for alkaline phosphatase, and expressed a significantly high level of SSEA-4 protein, except for one cell line (VSMUi001-A) whose properties were similar to those of the 5TF-piPSCs; that is, tightly packed and dome-like in shape, markedly positive for alkaline phosphatase, and expressing endogenous pluripotency genes (pOCT4, pSOX2, pNANOG, and pLIN28), significantly high levels of pluripotent proteins (OCT4, SOX2, NANOG, LIN28, and SSEA-1), and a significantly low level of SSEA-4 protein. VSMUi001-A and all 5F-piPSC lines formed embryoid bodies, underwent spontaneous cardiogenic differentiation with cardiac beating, expressed cardiomyocyte markers, and developed teratomas. In conclusion, in addition to the 4TF, LIN28 is required for the effective induction of piPSCs and the maintenance of their long-term self-renewal and pluripotency toward the development of all germ layers. These piPSCs have the potential applicability for veterinary science.

Differentiation Potential of Human Induced Pluripotent Stem Cells (iPSCs) to Nucleus Pulposus-Like Cells in Vitro

2012 ◽  
Vol 2 (1_suppl) ◽  
pp. s-0032-1319887-s-0032-1319887
Author(s):  
L. Jing ◽  
N. Christoforou ◽  
K. W. Leong ◽  
L. A. Setton ◽  
J. Chen
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Nucleus Pulposus ◽  
Pluripotent Stem Cells ◽  
Differentiation Potential ◽  
Induced Pluripotent

191 ROBUST GENERATION OF NEURAL STEM CELLS FROM PIG INDUCED PLURIPOTENT STEM CELLS FOR TRANSLATIONAL NEURAL REGENERATIVE MEDICINE

2014 ◽  
Vol 26 (1) ◽  
pp. 210
Author(s):  
A. Gallegos-Cardenas ◽  
K. Wang ◽  
E. T. Jordan ◽  
R. West ◽  
F. D. West ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Neural Differentiation ◽  
Neural Induction ◽  
Differentiation Potential ◽  
Induced Pluripotent ◽  
Human Ipsc

The generation of pig induced pluripotent stem cells (iPSC) opened the possibility to evaluate autologous neural cell therapy as a viable option for human patients. However, it is necessary to demonstrate whether pig iPSC are capable of in vitro neural differentiation similar to human iPSC in order to perform in vitro and in vivo comparative studies. Multiple laboratories have generated pig iPSC that have been characterised using pluripotent markers such as SSEA4 and POU5F1. However, correlations of pluripotent marker expression profiles among iPSC lines and their neural differentiation potential has not been fully explored. Because neural rosettes (NR) are composed of neural stem cells, our goal was to demonstrate that NR from pig iPSC can be generated, isolated, and expanded in vitro from multiple porcine iPSC lines similar to human iPSC and that the level of pluripotency in the starting porcine iPSC population (POUF51 and SSEA4 expression) could influence NRs development. Three lines of pig iPSC L1, L2, and L3 were cultured on matrigel-coated plates in mTeSR1 medium (Stemcell Technologies Inc., Vancouver, BC, Canada) and passaged every 3 to 4 days. For neural induction (NI), pig iPSC were disaggregated using dispase and plated. After 24 h, cells were maintained in N2 media [77% DMEM/F12, 10 ng mL–1 bovine fibroblast growth factor (bFGF), and 1X N2] for 15 days. To evaluate the differentiation potential to neuron and glial cells, NR were isolated, expanded in vitro and cultured for three weeks in AB2 medium (AB2, 1X ANS, and 2 mM L-Glutamine). Immunostaining assays were performed to determine pluripotent (POU5F1 and SSEA4), tight junction (ZO1), neural epithelial (Pax6 and Sox1), neuron (Tuj1), astrocyte (GFAP), and oligodendrocyte (O4) marker expression. Line L2 (POU5F1high and SSEA4low) showed a high potential to form NR (6.3.5%, P < 0.05) in comparison to the other 2 lines L1 (POU5F1low and SSEA4low) and L3 (POU5F1low and SSEA4high) upon NI. The NR immunocytochemistry results from Line L2 showed the presence of Pax6+ and Sox1– NRs cells at day 9 post-neural induction and that ZO1 started to localise at the apical border of NRs. At day 13, NRs cells were Pax6+ and Sox1+, and ZO1 was localised to the lumen of NR. After isolation and culture in vitro, NR cells expressed transcription factors PLAGL1, DACH1, and OTX2 through 2 passages, but were not detected in later passages. However, rosette cytoarchitecture was present up until passage 7 and were still Pax6+/Sox1+. NRs at passage 2 were cryopreserved and upon thaw showed normal NR morphology and were Pax6+/Sox1+. To characterise the plasticity of NRs, cells were differentiated. Tuj1 expression was predominant after differentiation indicating a bias towards a neuron phenotype. These results demonstrate that L2 pig iPSC (POUF51high and SSEA4low) have a high potential to form NR and neural differentiation parallels human iPSC neurulation events. Porcine iPSC should be considered as a large animal model for determining the safety and efficacy of human iPSC neural cell therapies.

305 TRANSPOSON-MEDIATED REPROGRAMMING OF LIVESTOCK SOMATIC CELLS TO INDUCED PLURIPOTENT STEM CELLS

2013 ◽  
Vol 25 (1) ◽  
pp. 300
Author(s):  
T. R. Talluri ◽  
D. Hermann ◽  
B. Barg-Kues ◽  
K. Debowski ◽  
R. Behr ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Insertional Mutagenesis ◽  
Somatic Cells ◽  
Embryonic Stem ◽  
Ips Cells ◽  
Sleeping Beauty ◽  
Major Step ◽  
Increased Risk ◽  
Induced Pluripotent

The elusive nature of embryonic stem cells in livestock makes reprogramming of somatic cells to induced pluripotent stem (iPS) cells a promising approach for targeted genetic modifications. The first attempts to produce iPS cells from livestock species were made using retro- and lentiviral vectors, which are associated with an increased risk of insertional mutagenesis and which are not easily removable after reprogramming. Here, we describe a nonviral method for the derivation of porcine and bovine iPS cells, using Sleeping Beauty (SB) and piggyBac (PB) transposon systems. The transposons encode the murine or primate reprogramming factors OCT4, SOX2, KLF4, MYC, and LIN28, separated by self-cleaving peptide sequences, respectively. In addition, the PB transposon cassette contains a NANOG-cDNA. The SB or PB transposon-reprogrammed porcine iPS cells expressed typical markers of embryonic stem cells (SSEA1, SSEA4, TRA-1-60, and endogenous stemness genes), showed long-term proliferation under feeder-free culture conditions, differentiated into cell types of the 3 germ layers in vitro, and formed teratomas after subcutaneous injection into immune-deficient nude mice. Both transposon systems are currently being tested in bovine fibroblasts. The results are a major step towards the derivation of authentic porcine and bovine iPS cells, in which the transposon transgenes can be eliminated after reprogramming.

Sign in / Sign up

Export Citation Format

Share Document