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Zhao X, Nie J, Tang Y, He W, Xiao K, Pang C, Liang X, Lu Y, Zhang M. Generation of Transgenic Cloned Buffalo Embryos Harboring the EGFP Gene in the Y Chromosome Using CRISPR/Cas9-Mediated Targeted Integration. Front Vet Sci 2020; 7:199. [PMID: 32426378 PMCID: PMC7212351 DOI: 10.3389/fvets.2020.00199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/25/2020] [Indexed: 11/16/2022] Open
Abstract
Sex control technology is of great significance in the production of domestic animals, especially for rapidly breeding water buffalo (bubalus bubalis), which served as a research model in the present study. We have confirmed that a fluorescence protein integrated into the Y chromosome is fit for sexing pre-implantation embryos in the mouse. Firstly, we optimized the efficiency of targeted integration of exogenous gene encoding enhanced green fluorescent protein (eGFP) and mCherry in Neuro-2a cells, mouse embryonic stem cells, mouse embryonic cells (NIH3T3), buffalo fetal fibroblast (BFF) cells. The results showed that a homology arm length of 800 bp on both sides of the target is more efficient that 300 bp or 300 bp/800 bp. Homology-directed repair (HDR)-mediated knock-in in BFF cells was also significantly improved when cells were supplemented with pifithrin-μ, which is a small molecule that inhibits the binding of p53 to mitochondria. Three pulses at 250 V resulted in the most efficient electroporation in BFF cells and 1.5 μg/mL puromycin was found to be the optimal concentration for screening. Moreover, Y-Chr-eGFP transgenic BFF cells and cloned buffalo embryos were successfully generated using CRISPR/Cas9-mediated gene editing combined with the somatic cell nuclear transfer (SCNT) technique. At passage numbers 6–8, the growth rate and cell proliferation rate were significantly lower in Y-Chr-eGFP transgenic than in non-transgenic BFF cells; the expression levels of the methylation-related genes DNMT1 and DNMT3a were similar; however, the expression levels of the acetylation-related genes HDAC1, HDAC2, and HDAC3 were significantly higher (p < 0.05) in Y-Chr-eGFP transgenic BFF cells compared with non-transgenic cells. Y-Chr-eGFP transgenic BFFs were used as donors for SCNT, the results showed that eGFP reporter is suitable for the visualization of the sex of embryos. The blastocyst rates of cloned buffalo embryos were similar; however, the cleavage rates of transgenic cloned embryos were significantly lower compared with control. In summary, we optimized the protocol for generating transgenic BFF cells and successfully generated Y-Chr-eGFP transgenic embryos using these cells as donors.
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Affiliation(s)
- Xiuling Zhao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, China
| | - Junyu Nie
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, China
| | - Yuyan Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, China
| | - Wengtan He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, China
| | - Kai Xiao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, China
| | - Chunying Pang
- Key Laboratory of Buffalo Genetics, Breeding and Reproduction Technology, Ministry of Agriculture and Buffalo Research Institute, Chinese Academy of Agricultural Science, Nanning, China
| | - Xianwei Liang
- Key Laboratory of Buffalo Genetics, Breeding and Reproduction Technology, Ministry of Agriculture and Buffalo Research Institute, Chinese Academy of Agricultural Science, Nanning, China
| | - Yangqing Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, China
| | - Ming Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Animal Reproduction Institute, Guangxi University, Nanning, China
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Identification of the Sex of Pre-implantation Mouse Embryos Using a Marked Y Chromosome and CRISPR/Cas9. Sci Rep 2019; 9:14315. [PMID: 31586114 PMCID: PMC6778187 DOI: 10.1038/s41598-019-50731-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 09/18/2019] [Indexed: 11/29/2022] Open
Abstract
Although numerous attempts have been made to alter the sex ratio of the progeny of mammals, the limitations of current technologies have prevented their widespread use in farm animals. The presence or absence of a Y chromosome determines whether a mammalian embryo develops as a male or female, and non-invasive genetic reporters such as fluorescence protein markers have been intensively applied in a variety of fields of research. To develop a non-invasive and instantaneous method for advance determination of the sex of embryos, we developed a Y chromosome-linked eGFP mouse line that stably expresses green fluorescent protein under the control of the CAG promoter. The development of the CRISPR/Cas9 system has made it easy to deliver an exogenous gene to a specific locus of a genome, and linking a tracer to the Y chromosome has simplified the process of predicting the sex of embryos collected by mating a Y-Chr-eGFP transgenic male with a wild-type female. XY embryos appeared green, under a fluorescence microscope, and XX embryos did not. Y chromosome-linked genes were amplified by nested PCR to further confirm the accuracy of this method, and the simultaneous transplantation of green and non-green embryos into foster mothers indicated that 100% accuracy was achieved by this method. Thus, the Y-Chr-eGFP mouse line provides an expeditious and accurate approach for sexing pre-implantation embryos and can be efficiently used for the pre-selection of sex.
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Generation of Venus fluorochrome expressing transgenic handmade cloned buffalo embryos using Sleeping Beauty transposon. Tissue Cell 2018; 51:49-55. [DOI: 10.1016/j.tice.2018.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 12/27/2022]
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Garrels W, Holler S, Taylor U, Herrmann D, Niemann H, Ivics Z, Kues WA. Assessment of fetal cell chimerism in transgenic pig lines generated by Sleeping beauty transposition. PLoS One 2014; 9:e96673. [PMID: 24811124 PMCID: PMC4014516 DOI: 10.1371/journal.pone.0096673] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 04/10/2014] [Indexed: 12/22/2022] Open
Abstract
Human cells migrate between mother and fetus during pregnancy and persist in the respective host for long-term after birth. Fetal microchimerism occurs also in twins sharing a common placenta or chorion. Whether microchimerism occurs in multiparous mammals such as the domestic pig, where fetuses have separate placentas and chorions, is not well understood. Here, we assessed cell chimerism in litters of wild-type sows inseminated with semen of transposon transgenic boars. Segregation of three independent monomeric transposons ensured an excess of transgenic over non-transgenic offspring in every litter. Transgenic siblings (n = 35) showed robust ubiquitous expression of the reporter transposon encoding a fluorescent protein, and provided an unique resource to assess a potential cell trafficking to non-transgenic littermates (n = 7) or mothers (n = 4). Sensitive flow cytometry, fluorescence microscopy, and real-time PCR provided no evidence for microchimerism in porcine littermates, or piglets and their mothers in both blood and solid organs. These data indicate that the epitheliochorial structure of the porcine placenta effectively prevents cellular exchange during gestation.
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Affiliation(s)
- Wiebke Garrels
- Institut für Nutztiergenetik, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Stephanie Holler
- Institut für Nutztiergenetik, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Ulrike Taylor
- Institut für Nutztiergenetik, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Doris Herrmann
- Institut für Nutztiergenetik, Friedrich-Loeffler-Institut, Mariensee, Germany
| | - Heiner Niemann
- Institut für Nutztiergenetik, Friedrich-Loeffler-Institut, Mariensee, Germany
| | | | - Wilfried A Kues
- Institut für Nutztiergenetik, Friedrich-Loeffler-Institut, Mariensee, Germany
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Germline transgenesis in pigs by cytoplasmic microinjection of Sleeping Beauty transposons. Nat Protoc 2014; 9:810-27. [DOI: 10.1038/nprot.2014.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Kues WA, Herrmann D, Barg-Kues B, Haridoss S, Nowak-Imialek M, Buchholz T, Streeck M, Grebe A, Grabundzija I, Merkert S, Martin U, Hall VJ, Rasmussen MA, Ivics Z, Hyttel P, Niemann H. Derivation and characterization of sleeping beauty transposon-mediated porcine induced pluripotent stem cells. Stem Cells Dev 2012; 22:124-35. [PMID: 22989381 DOI: 10.1089/scd.2012.0382] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The domestic pig is an important large animal model for preclinical testing of novel cell therapies. Recently, we produced pluripotency reporter pigs in which the Oct4 promoter drives expression of the enhanced green fluorescent protein (EGFP). Here, we reprogrammed Oct4-EGFP fibroblasts employing the nonviral Sleeping Beauty transposon system to deliver the reprogramming factors Oct4, Sox2, Klf4, and cMyc. Successful reprogramming to a pluripotent state was indicated by changes in cell morphology and reactivation of the Oct4-EGFP reporter. The transposon-reprogrammed induced pluripotent stem (iPS) cells showed long-term proliferation in vitro over >40 passages, expressed transcription factors typical of embryonic stem cells, including OCT4, NANOG, SOX2, REX1, ESRRB, DPPA5, and UTF1 and surface markers of pluripotency, including SSEA-1 and TRA-1-60. In vitro differentiation resulted in derivatives of the 3 germ layers. Upon injection of putative iPS cells under the skin of immunodeficient mice, we observed teratomas in 3 of 6 cases. These results form the basis for in-depth studies toward the derivation of porcine iPS cells, which hold great promise for preclinical testing of novel cell therapies in the pig model.
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Affiliation(s)
- Wilfried A Kues
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Mariensee, Germany.
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Garrels W, Holler S, Cleve N, Niemann H, Ivics Z, Kues WA. Assessment of fecundity and germ line transmission in two transgenic pig lines produced by sleeping beauty transposition. Genes (Basel) 2012; 3:615-33. [PMID: 24705079 PMCID: PMC3899982 DOI: 10.3390/genes3040615] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/10/2012] [Accepted: 09/14/2012] [Indexed: 01/12/2023] Open
Abstract
Recently, we described a simplified injection method for producing transgenic pigs using a non-autonomous Sleeping Beauty transposon system. The founder animals showed ubiquitous expression of the Venus fluorophore in almost all cell types. To assess, whether expression of the reporter fluorophore affects animal welfare or fecundity, we analyzed reproductive parameters of two founder boars, germ line transmission, and organ and cell specific transgene expression in animals of the F1 and F2 generation. Molecular analysis of ejaculated sperm cells suggested three monomeric integrations of the Venus transposon in both founders. To test germ line transmission of the three monomeric transposon integrations, wild-type sows were artificially inseminated. The offspring were nursed to sexual maturity and hemizygous lines were established. A clear segregation of the monomeric transposons following the Mendelian rules was observed in the F1 and F2 offspring. Apparently, almost all somatic cells, as well as oocytes and spermatozoa, expressed the Venus fluorophore at cell-type specific levels. No detrimental effects of Venus expression on animal health or fecundity were found. Importantly, all hemizygous lines expressed the fluorophore in comparable levels, and no case of transgene silencing or variegated expression was found after germ line transmission, suggesting that the insertions occurred at transcriptionally permissive loci. The results show that Sleeping Beauty transposase-catalyzed transposition is a promising approach for stable genetic modification of the pig genome.
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Affiliation(s)
- Wiebke Garrels
- Friedrich-Loeffler-Institut, Institute of Farm Animal Genetics, Höltystraße 10, 31535 Neustadt, Germany.
| | - Stephanie Holler
- Friedrich-Loeffler-Institut, Institute of Farm Animal Genetics, Höltystraße 10, 31535 Neustadt, Germany.
| | - Nicole Cleve
- Friedrich-Loeffler-Institut, Institute of Farm Animal Genetics, Höltystraße 10, 31535 Neustadt, Germany.
| | - Heiner Niemann
- Friedrich-Loeffler-Institut, Institute of Farm Animal Genetics, Höltystraße 10, 31535 Neustadt, Germany.
| | - Zoltan Ivics
- Paul-Ehrlich-Institute, Paul-Ehrlich-Straße 51-59, 63225 Langen, Germany.
| | - Wilfried A Kues
- Friedrich-Loeffler-Institut, Institute of Farm Animal Genetics, Höltystraße 10, 31535 Neustadt, Germany.
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