CRISPR/Cas9-Mediated Integration of Large Transgene into Pig CEP112 Locus

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) is a precise genome manipulating tool that can produce targeted gene mutations in various cells and organisms. Although CRISPR/Cas9 can efficiently generate gene knockout, the gene knock-in (KI) efficiency mediated by homology-directed repair remains low, especially for large fragment integration. In this study, we established an efficient method for the CRISPR/Cas9-mediated integration of large transgene cassette, which carries salivary gland-expressed multiple digestion enzymes (≈ 20 kbp) in CEP112 locus in pig fetal fibroblasts (PFFs). Our results showed that using an optimal homology donor with a short and a long arm yielded the best CRISPR/Cas9-mediated KI efficiency in CEP112 locus, and the targeting efficiency in CEP112 locus was higher than in ROSA26 locus. The CEP112 KI cell lines were used as nuclear donors for somatic cell nuclear transfer to create genetically modified pigs. We found that KI pig (705) successfully expressed three microbial enzymes (β-glucanase, xylanase, and phytase) in salivary gland. This finding suggested that the CEP112 locus supports exogenous gene expression by a tissue-specific promoter. In summary, we successfully targeted CEP112 locus in pigs by using our optimal homology arm system and established a modified pig model for foreign digestion enzyme expression in the saliva.

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CRISPR/Cas9-mediated integration of large transgene into pig potential safe harbor

10.1101/722348 ◽

2019 ◽

Author(s):

Guoling Li ◽

Xianwei Zhang ◽

Haoqiang Wang ◽

Jianxin Mo ◽

Cuili Zhong ◽

...

Keyword(s):

Salivary Gland ◽

Nuclear Transfer ◽

Gene Mutations ◽

Safe Harbor ◽

Knock Out ◽

Homology Directed Repair ◽

Genes Expression ◽

Fetal Fibroblasts ◽

Tissue Specific Promoter ◽

Exogenous Genes

ABSTRACTClustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (Cas9) is a precise genome manipulating tool which can produce targeted gene mutations in various cells and organisms. Although CRISPR/Cas9 can efficiently generate gene knock-out, the gene knock-in efficiency mediated by homology-directed repair (HDR) remains low, especially for large fragment integration. In this study, we established an efficient method for CRISPR/Cas9-mediated integration of large transgene cassette carrying salivary gland-expressing multiple digestion enzymes (≈ 20 kbp) in CEP112 locus in pig fetal fibroblasts. Our results showed that using homologous donor with a short left arm and a long right arm yielded the best CRISPR/Cas9-mediated knock-in efficiency, and the targeting efficiency in potential safe harbor CEP112 locus are higher than ROSA26 locus. The CEP112 knock-in cell lines were used as nuclear donors for somatic cell nuclear transfer to create genetically modified pigs. We found that knock-in pig (705) successfully expressed three microbial enzymes (β-glucanase, xylanase, and phytase) in salivary gland, suggesting potential safe harbor CEP112 locus supports exogenous genes expression by a tissue-specific promoter. In summary, we successfully targeted CEP112 locus using our optimal homology arm system for precise modification of pigs, and established a modified pig model for foreign digestion enzyme expression in saliva.

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Efficient TALEN-mediated gene knockin at the bovine Y chromosome and generation of a sex-reversal bovine

Cellular and Molecular Life Sciences ◽

10.1007/s00018-021-03855-1 ◽

2021 ◽

Author(s):

Ming Wang ◽

ZhaoLin Sun ◽

Fangrong Ding ◽

Haiping Wang ◽

Ling Li ◽

...

Keyword(s):

Y Chromosome ◽

Nuclear Transfer ◽

Sex Reversal ◽

Practical Application ◽

Transcription Activator ◽

New Methods ◽

Fetal Fibroblasts ◽

Male Phenotype ◽

Solid Foundation ◽

First Time

AbstractFunctional elucidation of bovine Y-chromosome genes requires available genome editing technologies. Meanwhile, it has yet to be proven whether the bovine Sry gene is the main or single factor involved in the development of the male phenotype in bovine. Here, we efficiently knocked out four Y-linked genes (Sry, ZFY, DDX3Y, and EIF2S3Y) in bovine fetal fibroblasts (BFFs) with transcription activator-like effector nucleases (TALENs) individually. Furthermore, we used TALEN-mediated gene knockin at the Sry gene and generated a sex-reversal bovine by somatic cell nuclear transfer (SCNT). The resulting bovine had only one ovary and was sterile. We demonstrate, for the first time, that the Sry gene is an important sex-determining gene in bovine. Our method lays a solid foundation for detecting the biology of the bovine Y chromosome, as it may provide an alternative biological model system for the study of mammalian sex determination, and new methods for the practical application in agricultural, especially for sex predetermination.

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The Role of RNA in DNA Breaks, Repair and Chromosomal Rearrangements

Biomolecules ◽

10.3390/biom11040550 ◽

2021 ◽

Vol 11 (4) ◽

pp. 550

Author(s):

Matvey Mikhailovich Murashko ◽

Ekaterina Mikhailovna Stasevich ◽

Anton Markovich Schwartz ◽

Dmitriy Vladimirovich Kuprash ◽

Aksinya Nicolaevna Uvarova ◽

...

Keyword(s):

Chromosomal Rearrangements ◽

Gene Mutations ◽

Nonhomologous End Joining ◽

Published Data ◽

Dna Double Strand Breaks ◽

Dna Breaks ◽

End Joining ◽

Homology Directed Repair ◽

Chromosome Aberration Frequency

Incorrect reparation of DNA double-strand breaks (DSB) leading to chromosomal rearrangements is one of oncogenesis’s primary causes. Recently published data elucidate the key role of various types of RNA in DSB formation, recognition and repair. With growing interest in RNA biology, increasing RNAs are classified as crucial at the different stages of the main pathways of DSB repair in eukaryotic cells: nonhomologous end joining (NHEJ) and homology-directed repair (HDR). Gene mutations or variation in expression levels of such RNAs can lead to local DNA repair defects, increasing the chromosome aberration frequency. Moreover, it was demonstrated that some RNAs could stimulate long-range chromosomal rearrangements. In this review, we discuss recent evidence demonstrating the role of various RNAs in DSB formation and repair. We also consider how RNA may mediate certain chromosomal rearrangements in a sequence-specific manner.

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Dynamic Methylation Changes of DNA and H3K4 by RG108 Improve Epigenetic Reprogramming of Somatic Cell Nuclear Transfer Embryos in Pigs

Cellular Physiology and Biochemistry ◽

10.1159/000494598 ◽

2018 ◽

Vol 50 (4) ◽

pp. 1376-1397 ◽

Cited By ~ 5

Author(s):

Yanhui Zhai ◽

Zhiren Zhang ◽

Hao Yu ◽

Li Su ◽

Gang Yao ◽

...

Keyword(s):

Dna Methylation ◽

Somatic Cell ◽

Histone Modifications ◽

Somatic Cell Nuclear Transfer ◽

Nuclear Transfer ◽

Histone H3 ◽

Dna Demethylation ◽

Epigenetic Reprogramming ◽

Expression Levels ◽

Fetal Fibroblasts

Background/Aims: DNA methylation and histone modifications are essential epigenetic marks that can significantly affect the mammalian somatic cell nuclear transfer (SCNT) embryo development. However, the mechanisms by which the DNA methylation affects the epigenetic reprogramming have not been fully elucidated. Methods: In our study, we used quantitative polymerase chain reaction (qPCR), Western blotting, immunofluorescence staining (IF) and sodium bisulfite genomic sequencing to examine the effects of RG108, a DNA methyltransferase inhibitor (DNMTi), on the dynamic pattern of DNA methylation and histone modifications in porcine SCNT embryos and investigate the mechanism by which the epigenome status of donor cells’ affects SCNT embryos development and the crosstalk between epigenetic signals. Results: Our results showed that active DNA demethylation was enhanced by the significantly improving expression levels of TET1, TET2, TET3 and 5hmC, and passive DNA demethylation was promoted by the remarkably inhibitory expression levels of DNMT1, DNMT3A and 5mC in embryos constructed from the fetal fibroblasts (FFs) treated with RG108 (RG-SCNT embryos) compared to the levels in embryos from control FFs (FF-SCNT embryos). The signal intensity of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 9 acetylation (H3K9Ac) was significantly increased and the expression levels of H3K4 methyltransferases were more than 2-fold higher expression in RG-SCNT embryos. RG-SCNT embryos had significantly higher cleavage and blastocyst rates (69.3±1.4%, and 24.72±2.3%, respectively) than FF-SCNT embryos (60.1±2.4% and 18.38±1.9%, respectively). Conclusion: Dynamic changes in DNA methylation caused by RG108 result in dynamic alterations in the patterns of H3K4me3, H3K9Ac and histone H3 lysine 9 trimethylation (H3K9me3), which leads to the activation of embryonic genome and epigenetic modification enzymes associated with H3K4 methylation, and contributes to reconstructing normal epigenetic modifications and improving the developmental efficiency of porcine SCNT embryos.

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63 IMPROVED IN VITRO DEVELOPMENT OF PORCINE EMBRYOS PRODUCED BY NUCLEAR TRANSFER, IVF AND PARTHENOGENESIS

Reproduction Fertility and Development ◽

10.1071/rdv17n2ab63 ◽

2005 ◽

Vol 17 (2) ◽

pp. 181 ◽

Cited By ~ 1

Author(s):

D. Sage ◽

P. Hassel ◽

B. Petersen ◽

W. Mysegades ◽

P. Westermann ◽

...

Keyword(s):

Nuclear Transfer ◽

Culture Media ◽

Cumulus Cells ◽

Cell Number ◽

Foster Mother ◽

Chi Square ◽

Fetal Fibroblasts ◽

Blastocyst Rate ◽

Parthenogenetic Embryos

Porcine nuclear transfer (NT) is an inefficient process and it is necessary to use as many as 120 NT embryos for each foster mother to obtain small litters of live piglets. In these experiments, we evaluated the effects of culture atmosphere and medium on the development of NT embryos by monitoring blastocyst rate and cell number of Day 6 blastocysts. Age matched IVF and parthenogenetic embryos were also evaluated for comparison. For all experiments a pool of oocytes was aspirated from ovaries collected in a local abattoir. Following aspiration, oocytes were allowed to mature for 40 h in North Carolina State University (NCSU)-37 medium (supplemented with cAMP and hCG/eCG for the first 22 h). After removal of the cumulus cells, denuded oocytes with polar bodies were selected for NT, enucleated, fused with fetal fibroblasts, and sequentially activated electrically and chemically by 3 h of treatment with 6-dimethylaminopurine (6-DMAP). A second group of oocytes from the same denuded pool were maintained in TL-HEPES medium and activated in parallel with the NT group to produce parthenogenetic embryos. A third group was fertilized with frozen-thawed epididymal semen and co-cultured for ∼12 h to give IVF embryos. All three treatment groups were subdivided into a control subgroup and an experimental subgroup. In the first experiment, we compared the effects of atmosphere (20% vs. 5% oxygen) on in vitro embryonic development in NCSU-23 medium. In the second experiment, we used only the 5% oxygen concentration and compared different culture media. One subgroup was maintained in standard NCSU-23 medium and the second subgroup was cultured in a two-step system for the first 58 h in modified NCSU-23 (without glucose but supplemented with 2.0 mM lactate and 0.2 mM pyruvate), followed by addition of glucose to give a final concentration of 5.55 mM. Data were statistically analyzed by analysis of variance and chi square test. Blastocyst rate and mean cell number in all three embryo groups were improved under 5% oxygen. The most dramatic effect was observed in the NT group, in which the blastocyst rate increased significantly (P < 0.001) from 6.7% ± 5.9 (n = 279) to 19.6% ± 8.9 (n = 250) and mean cell number increased from 17.7 ± 12.1 to 25.8 ± 10.3 cells per blastocyst. With 5% oxygen there was also an increase of blastocyst rates and mean cell numbers in both IVF and parthenogenetic groups. In the second experiment, blastocyst rate for NT embryos increased significantly (P < 0.05) from 21.8% ± 7.6 (n = 242) in conventional NCSU-23 to 31.5% ± 11.0 (n = 271) in the modified system whereas there was almost no difference in the mean cell number of both groups (29.2 ± 4.3 vs. 31.5 ± 5.3). In the groups of IVF and parthenogenetic embryos no difference was found. These results indicate that both the reduced oxygen and the modified culture medium are important for pre-implantation development of porcine nuclear transfer embryos.

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Generation of ETV5 Knockout Pigs with CRISPR/Cas9

Indian Journal of Animal Research ◽

10.18805/ijar.b-1327 ◽

2021 ◽

Author(s):

Mao Zhang ◽

Gengyuan Cai ◽

Rong Zhou ◽

Huaqiang Yang

Keyword(s):

Nuclear Transfer ◽

Gene Editing ◽

Seminiferous Tubules ◽

Rt Pcr ◽

Self Renewal ◽

Progressive Loss ◽

Elisa Testing ◽

Fetal Fibroblasts ◽

Normal Spermatogenesis ◽

Hematoxylin And Eosin

Background: Ets variant factor 5 (ETV5) plays an important regulatory role in mouse Spermatogonial stem cells (SSCs) self-renewal. ETV5 knockout (KO) mice exhibit a progressive loss of SSCs and resulting in a Sertoli cell-only phenotype. The current study was aimed to use gene editing technology to obtain ETV5-KO pigs as a model for studying the apoptosis mechanism of SSCs and further clarify the function of ETV5 gene in pigs.Methods: A gene editing plasmid for the porcine ETV5 gene was constructed, transfected into porcine fetal fibroblasts by electroporation to obtain ETV5-KO cells. ETV5-KO cells were used as donors to prepare ETV5-KO pigs by somatic cell nuclear transfer (SCNT). Testis tissues were collected for hematoxylin and eosin (HE), immunohistochemistry (IHC), RT-PCR testing and blood for ELISA testing from ETV5-KO pig.Result: In the present study, we used the CRISPR/Cas9 system and SCNT to generate homozygous ETV5-KO pigs. We observed 3 phenotypes in these pigs: normal testis development after birth, the SSCs in the seminiferous tubules did not show obviously extinction at sexual maturity and normal spermatogenesis.

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Streptolysin-O Treatment of Fetal Fibroblasts Improves Cell Fusion and In Vitro Development of Porcine Nuclear Transfer Embryos

Journal of Reproduction and Development ◽

10.1262/jrd.20047 ◽

2009 ◽

Vol 55 (3) ◽

pp. 236-239 ◽

Cited By ~ 5

Author(s):

Kenji NARUSE ◽

Yan-Shi QUAN ◽

Baek-Chul KIM ◽

Su-Min CHOI ◽

Chang-Sik PARK ◽

...

Keyword(s):

Cell Fusion ◽

Nuclear Transfer ◽

In Vitro Development ◽

Streptolysin O ◽

Fetal Fibroblasts ◽

Vitro Development

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Generation of Dwarf Goat (Capra hircus) Clones Following Nuclear Transfer with Transfected and Nontransfected Fetal Fibroblasts and In Vitro-Matured Oocytes1

Biology of Reproduction ◽

10.1095/biolreprod64.3.849 ◽

2001 ◽

Vol 64 (3) ◽

pp. 849-856 ◽

Cited By ~ 168

Author(s):

C.L. Keefer ◽

H. Baldassarre ◽

R. Keyston ◽

B. Wang ◽

B. Bhatia ◽

...

Keyword(s):

Nuclear Transfer ◽

Capra Hircus ◽

Fetal Fibroblasts

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102 RABBIT CLONING: HISTONE ACETYLATION STATUS OF DONOR CELLS AND CLONED EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv19n1ab102 ◽

2007 ◽

Vol 19 (1) ◽

pp. 168

Author(s):

V. Zakhartchenko ◽

F. Yang ◽

R. Hao ◽

E. Wolf

Keyword(s):

Histone Acetylation ◽

Nuclear Transfer ◽

Epigenetic Mark ◽

Cloning Efficiency ◽

Developmental Potential ◽

Acetylation Status ◽

Donor Cells ◽

Fetal Fibroblasts

Epigenetic status of the genome of a donor nucleus is likely to be associated with the developmental potential of cloned embryos produced by somatic cell nuclear transfer (SCNT). Prevention of epigenetic errors by manipulation of the epigenetic status of donor cells is expected to result in improvement of cloning efficiency. In this study, we transferred cultured rabbit cumulus cells (RCC) and fetal fibroblasts (RFF) from genetically marked rabbits (Ali/Bas) into metaphase II (MII) oocytes and analyzed the levels of histone H3K9 acetylation in donor cells and cloned embryos. We also assessed the correlation between the histone acetylation status of donor cells and cloned embryos and their developmental potential. To test whether alteration of the histone acetylation status affects development of cloned embryos, we treated donor cells with sodium butyrate (NaBu), a histone deacetylase inhibitor. Further, we tried to improve cloning efficiency by chimeric complementation of cloned embryos with one or two blastomeres from in vitro-fertilized or parthenogenetic embryos. Histone acetylation in donor cells and cloned embryos was detected by anti-acH3K9 antibody using Western immunoblot analysis or immunochemistry, respectively. Data were analyzed by chi-square (developmental rates) or Student-Newman-Keuls (histone acetylation) test. The levels of acetylated histone H3K9 were higher in RCCs than in RFFs (P < 0.05). Although the type of donor cells did not affect development to blastocyst, after transfer into recipients, RCC-cloned embryos induced a higher initial pregnancy rate as compared to RFF-cloned embryos (40% vs. 20%; P < 0.05). However, almost all pregnancies with either type of cloned embryos were lost by the middle of gestation and only one fully developed; a live RCC-derived rabbit was obtained. Treatment of RFFs with NaBu significantly (P < 0.05) increased the level of histone H3K9/14 acetylation and the proportion of nuclear transfer embryos developing to blastocyst (49% vs. 33% with non-treated RFF; P < 0.05). The distribution of signals for acH3K9 in either group of cloned embryos did not resemble that in in vivo-fertilized embryos, suggesting that reprogramming of this epigenetic mark is aberrant in cloned rabbit embryos and cannot be corrected by treatment of donor cells with NaBu. Aggregation of embryos cloned from NaBu-treated RFFs with blastomeres from in vivo-derived embryos improved development to blastocyst, but no cloned offspring were obtained. Two live cloned rabbits were produced from this donor cell type only after aggregation of cloned embryos with a parthenogenetic blastomere. Our study demonstrates that the levels of histone acetylation in donor cells and cloned embryos correlate with their developmental potential and can be a useful epigenetic mark to predict efficiency of SCNT rabbits. This work was supported by the Bayerische Forschungsstiftung and by Therapeutic Human Polyclonals, Inc.

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30 NUCLEAR AND MICROTUBULE DYNAMICS IN SOMATIC CELL NUCLEAR TRANSFER SHEEP EMBRYOS ACTIVATED WITH T-DIMETHYLAMINOPURINE AND CYCLOHEXIMIDE

Reproduction Fertility and Development ◽

10.1071/rdv18n2ab30 ◽

2006 ◽

Vol 18 (2) ◽

pp. 123

Author(s):

G. Coppola ◽

B.-G. Jeon ◽

B. Alexander ◽

E. St. John ◽

D. H. Betts ◽

...

Keyword(s):

Cell Cycle ◽

Somatic Cell ◽

Somatic Cell Nuclear Transfer ◽

Nuclear Transfer ◽

Laser Scanning ◽

Cell Cycle Progression ◽

Treated Group ◽

Blastocyst Development ◽

Fetal Fibroblasts

The early reprogramming events following somatic cell nuclear transfer (SCNT) determine the fate of the cloned embryo and its development to a healthy viable offspring. In the present study, we undertook a detailed immunocytochemical study of the patterns of both microtubules and chromatin during the first cell cycle of sheep nuclear transfer embryos after fusion and artificial activation using either 6-dimethylaminopurine (6-DMAP) or cycloheximede (CHX). Sheep oocytes were collected from abattoir ovaries and matured in vitro for 18-20 h and enucleated; fetal fibroblasts were transplanted using standard SCNT techniques. Reconstructed cell-cytoplast couplets were fused and activated with ionomycin, followed by culture in two separate groups containing 6-DMAP (2 mM) or CHX (10 �g/mL) for 3 h. Following activation, embryos were cultured in in vitro culture (IVC) medium for blastocyst development. Embryos (n = 15, 3 replicates) were randomly removed from culture at various time points and stained using standard immunocytochemical methods to observe microtubule and nuclear configurations. Images were captured using laser scanning confocal microscopy. Results reveled that at 1 h post-fusion, 63.3% of reconstructed embryos underwent nuclear envelope breakdown (NEBD) and premature chromosome condensation (PCC) was apparent as chromosomes were situated on a non-polar spindle. The remaining embryos showed abnormal spindle and DNA configurations including chromosome outliers, congression failure, and non-NEBD. At 1 h post-activation (hpa), the embryos treated with 6-DMAP had already formed a clearly visible pronucleus (diameter 6-8 �m), whereas in the CHX-treated group, none of the embryos were at pronuclear stage; instead most of the latter embryos showed two masses of chromatin. At 1 hpa, 6-DMAP- and CHX-treated embryos showed one swelled pronucleus with a mean diameter of 8.4 � 1.3 �m and 25.8 � 0.8 �m, respectively (P < 0.05). At 16 hpa, embryos from both treatment groups still showed one swelled pronucleus. In the 6-DMAP-treated embryos, most of the embryos showed a metaphase spindle with aligned chromosomes of the first mitotic division as early as 18-10 hpa, whereas in the CHX-treated group embryos were still at the pronuclear stage. Typical 2-cell division was seen in most of the 6-DMAP-treated embryos between 24 and 30 hpa, but it was slightly delayed in CHX-treated embryos (32-35 hpa). Blastocyst development rates in the 6-DMAP- and CHX-treated groups were 21.4 � 5.6% and 14.0 � 6.3%, respectively (P < 0.05). In summary, artificial activating agents 6-DMAP and CHX exhibited different effects on chromatin remodeling, cell cycle progression, and the degree of pronuclear swelling which may explain the poor developmental rates and abnormal chromosome complements observed for cloned embryos. This work was funded by NSERC, OMAF, and International Council for Canadian Studies.

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