A Rapid and Cost-Effective Method for Genotyping Genome-Edited Animals: A Heteroduplex Mobility Assay Using Microfluidic Capillary Electrophoresis

Application of PCR-RFLP for quick identification of MSTN mutants in MSTN mutant pig breeding

Knockout of the MSTN gene is linked to the enlarged tongue, and it causes suckling difficulty in animals. The suckling difficulty has a severe effect on animal mortality. Thus, special care was required to ensure their survivability. Here, it is critical to promptly ascertain the genotype of all pigs after birth. The main objective of the present study was to develop the restriction enzyme-mediated PCR-RFLP assay for MSTN mutant pig genotyping. To accomplish this, conserved oligonucleotide primer and restriction site were deduced according to the mutated sequence of the MSTN mutant pigs. PCR amplification yielded a 176 bp band for all homozygous MSTN mutant (MSTN-/-), heterozygous MSTN mutant (MSTN+/-) and wild-type (WT) pigs. However, MSTN+/- samples produced two fragments with 176 and 87 bp, and WT samples produced one fragment with 87 bp after being digested by BstNI. MSTN-/- samples were not digested by BstNI and yielded a 176 bp band. Thus, we were able to determine the genotype of all pigs using BstNI restriction enzyme-mediated PCR-RFLP method. Overall, the present study reported a simple and fast PCR-RFLP genotyping method for MSTN mutant pig breeding. The present study may contribute to the establishment of commercial breeding systems and the production of double muscle pigs.

Excess of guide RNA reduces knockin efficiency and drastically increases on-target large deletions

CRISPR-Cas9 cleavage efficacy and accuracy are the main challenges gene editing faces, and they are particularly affected by the optimal formation of the ribonucleoprotein (RNP) complex. We used nano differential scanning fluorimetry, a label and immobilization-free assay, to demonstrate that an equimolar ratio of Cas9 and guide RNA (gRNA) is optimal for RNP complex formation. We almost achieved 50% of green fluorescent protein (GFP) to blue fluorescent protein (BFP) conversion using a biallelic homozygous GFP human induced pluripotent stem cell line, when 0.4 μM of Cas9, equimolar Cas9/gRNA ratio and 2 μM of single-stranded oligonucleotide, were used and showed that increasing Cas9/gRNA ratio did not further improve KI efficiency. Additionally, excess gRNA decreased point mutation KI efficiency in rat embryos and drastically increased the occurrence of on-target large deletions. These findings highlight the importance of CRISPR/Cas9 stoichiometric optimization to ensure efficient and accurate KI generation, which will be applicable to other in vitro as well as in vivo models.

Review of CRISPR/Cas Systems on Detection of Nucleotide Sequences

Nowadays, with the rapid development of biotechnology, the CRISPR/Cas technology in particular has produced many new traits and products. Therefore, rapid and high-resolution detection methods for biotechnology products are urgently needed, which is extremely important for safety regulation. Recently, in addition to being gene editing tools, CRISPR/Cas systems have also been used in detection of various targets. CRISPR/Cas systems can be successfully used to detect nucleic acids, proteins, metal ions and others in combination with a variety of technologies, with great application prospects in the future. However, there are still some challenges need to be addressed. In this review, we will list some detection methods of genetically modified (GM) crops, gene-edited crops and single-nucleotide polymorphisms (SNPs) based on CRISPR/Cas systems, hoping to bring some inspiration or ideas to readers.

CD4+ and CD8+ regulatory T cell characterization in the rat using a unique transgenic Foxp3-EGFP model

BACKGROUND

Regulatory T cells (Treg) in diverse species include CD4⁺ and CD8⁺ T cells. In all species, CD8⁺ Treg have been only partially characterized and there is no rat model in which CD4⁺ and CD8⁺ FOXP3⁺ Treg are genetically tagged.

RESULTS

We generated a Foxp3-EGFP rat transgenic line in which FOXP3 gene was expressed and controlled EGFP. CD4⁺ and CD8⁺ T cells were the only cells that expressed EGFP, in similar proportion as observed with anti-FOXP3 antibodies and co-labeled in the same cells. CD4⁺EGFP⁺ Treg were 5-10 times more frequent than CD8⁺EGFP⁺ Treg. The suppressive activity of CD4⁺ and CD8⁺ Treg was largely confined to EGFP⁺ cells. RNAseq analyses showed similarities but also differences among CD4⁺ and CD8⁺ EGFP⁺ cells and provided the first description of the natural FOXP3⁺CD8⁺ Treg transcriptome. In vitro culture of CD4⁺ and CD8⁺ EGFP^- cells with TGFbeta and IL-2 generated induced EGFP⁺ Treg. CD4⁺ and CD8⁺ EGFP⁺ Treg were expanded upon in vivo administration of a low dose of IL-2.

CONCLUSIONS

This new and unique rat line constitutes a useful model to identify and isolate viable CD4⁺ and CD8⁺ FOXP3⁺ Treg. Additionally, it allows to identify molecules expressed in CD8⁺ Treg that may allow to better define their phenotype and function not only in rats but also in other species.

Transgenesis and Genome Engineering: A Historical Review

Our ability to modify DNA molecules and to introduce them into mammalian cells or embryos almost appears in parallel, starting from the 1970s of the last century. Genetic engineering techniques rapidly developed between 1970 and 1980. In contrast, robust procedures to microinject or introduce DNA constructs into individuals did not take off until 1980 and evolved during the following two decades. For some years, it was only possible to add transgenes, de novo, of different formats, including artificial chromosomes, in a variety of vertebrate species or to introduce specific mutations essentially in mice, thanks to the gene-targeting methods by homologous recombination approaches using mouse embryonic stem (ES) cells. Eventually, genome-editing tools brought the possibility to add or inactivate DNA sequences, at specific sites, at will, irrespective of the animal species involved. Together with a variety of additional techniques, this chapter will summarize the milestones in the transgenesis and genome engineering fields from the 1970s to date.

Multimodality imaging and transciptomics to phenotype mitral valve dystrophy in a unique knock-in Filamin-A rat model

AIMS

Degenerative mitral valve dystrophy (MVD) leading to mitral valve prolapse is the most frequent form of MV disease, and there is currently no pharmacological treatment available. The limited understanding of the pathophysiological mechanisms leading to MVD limits our ability to identify therapeutic targets. This study aimed to reveal the main pathophysiological pathways involved in MVD via the multimodality imaging and transcriptomic analysis of the new and unique Knock-In (KI) rat model for the FlnA-P637Q mutation associated-MVD.

METHODS AND RESULTS

WT and KI rats were evaluated morphologically, functionally, and histologically between 3-week-old and 3-to-6-month-old based on Doppler echocardiography, 3D micro-computed tomography (microCT), and standard histology. RNA-sequencing and Assay for Transposase-Accessible Chromatin (ATAC-seq) were performed on 3-week-old WT and KI mitral valves and valvular cells, respectively, to highlight the main signaling pathways associated with MVD. Echocardiographic exploration confirmed MV elongation (2.0 ± 0.1  mm versus 1.8 ± 0.1, p = 0.001), as well as MV thickening and prolapse in KI animals compared to WT at 3 weeks. 3D MV volume quantified by microCT was significantly increased in KI animals (+58% versus WT, p = 0.02). Histological analyses revealed a myxomatous remodeling in KI MV characterized by proteoglycans accumulation. A persistent phenotype was observed in adult KI rats. Signaling pathways related to extracellular matrix homeostasis, response to molecular stress, epithelial cell migration, endothelial to mesenchymal transition, chemotaxis and immune cell migration, were identified based on RNA-seq analysis. ATAC-seq analysis points to the critical role of TGF-β and inflammation in the disease.

CONCLUSION

The KI FlnA-P637Q rat model mimics human myxomatous mitral valve dystrophy, offering a unique opportunity to decipher pathophysiological mechanisms related to this disease. Extracellular matrix organization, epithelial cell migration, response to mechanical stress, and a central contribution of immune cells are highlighted as the main signaling pathways leading to myxomatous mitral valve dystrophy. Our findings pave the road to decipher underlying molecular mechanisms and the specific role of distinct cell populations in this context.

IL-34 deficiency impairs FOXP3+ Treg function in a model of autoimmune colitis and decreases immune tolerance homeostasis

Background

Immune homeostasis requires fully functional Tregs with a stable phenotype to control autoimmunity. Although IL‐34 is a cytokine first described as mainly involved in monocyte cell survival and differentiation, we recently described its expression by CD8⁺ Tregs in a rat model of transplantation tolerance and by activated FOXP3⁺ CD4⁺ and CD8⁺ Tregs in human healthy individuals. However, its role in autoimmunity and potential in human diseases remains to be determined.

Methods

We generated Il34^−/− rats and using both Il34^−/− rats and mice, we investigated their phenotype under inflammatory conditions. Using Il34^−/− rats, we further analyzed the impact of the absence of expression of IL‐34 for CD4⁺ Tregs suppressive function. We investigated the potential of IL‐34 in human disease to prevent xenogeneic GVHD and human skin allograft rejection in immune humanized immunodeficient NSG mice. Finally, taking advantage of a biocollection, we investigated the correlation between presence of IL‐34 in the serum and kidney transplant rejection.

Results

Here we report that the absence of expression of IL‐34 in Il34^−/− rats and mice leads to an unstable immune phenotype, with production of multiple auto‐antibodies, exacerbated under inflammatory conditions with increased susceptibility to DSS‐ and TNBS‐colitis in Il34^−/− animals. Moreover, we revealed the striking inability of Il34^−/− CD4⁺ Tregs to protect Il2rg^−/− rats from a wasting disease induced by transfer of pathogenic cells, in contrast to Il34^+/+ CD4⁺ Tregs. We also showed that IL‐34 treatment delayed EAE in mice as well as GVHD and human skin allograft rejection in immune humanized immunodeficient NSG mice. Finally, we show that presence of IL‐34 in the serum is associated with a longer rejection‐free period in kidney transplanted patients.

Conclusion

Altogether, our data emphasize on the crucial necessity of IL‐34 for immune homeostasis and for CD4⁺ Tregs suppressive function. Our data also shows the therapeutic potential of IL‐34 in human transplantation and auto‐immunity.

Highlights

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Absence of expression of IL‐34 in Il34^−/− rats and mice leads to an unstable immune phenotype, with a production of multiple auto‐antibodies and exacerbated immune pathology under inflammatory conditions.

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Il34^−/− CD4⁺ Tregs are unable to protect Il2rg^−/− rats from colitis induced by transfer of pathogenic cells.

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IL‐34 treatment delayed EAE in mice, as well as acute GVHD and human skin allograft rejection in immune‐humanized immunodeficient NSG mice.

Anti-CD45RC antibody immunotherapy prevents and treats experimental Autoimmune PolyEndocrinopathy Candidiasis Ectodermal Dystrophy syndrome

Targeted monoclonal antibody (mAb) therapies show great promise for the treatment of transplant rejection and autoimmune diseases by inducing more specific immunomodulatory effects than broadly immunosuppressive drugs routinely used. We recently described the therapeutic advantage of targeting CD45RC, expressed at high levels by conventional T cells (Tconv, CD45RChigh), their precursors and terminally differentiated T (TEMRA) cells, but not by regulatory T cells (Tregs, CD45RClow/-). We demonstrated efficacy of anti-CD45RC mAb treatment in transplantation but its potential has not been examined in autoimmune diseases. APECED is a rare genetic syndrome caused by loss-of-function mutations of the key central tolerance mediator, autoimmune regulator (AIRE) leading to abnormal auto-reactive T cell responses and autoantibodies production. Herein, we showed that, in a rat model of APECED syndrome, anti-CD45RC mAb was effective both as prevention and treatment of autoimmune manifestations and inhibited autoantibody development. Anti-CD45RC mAb intervention depleted CD45RChigh T cells, inhibited CD45RChigh B cells, and restored the Treg/Tconv ratio and the altered Tregs transcriptomic profile. In APECED patients, CD45RC was significantly increased in peripheral blood T cells and lesioned organs from APECED patients were infiltrated by CD45RChigh cells. Our observations highlight the potential role for CD45RChigh cells in the pathogenesis of experimental and human APECED syndrome and the potential of anti-CD45RC antibody treatment.

Green Fluorescent Protein Tagged Polycistronic Reporter System Reveals Functional Editing Characteristics of CRISPR-Cas

The green fluorescent protein (GFP)-based reporter system has been widely harnessed as a quick quantitative activity assessment method for characterizing CRISPR-Cas via flow cytometry. However, due to the small size (738 nt) of the GFP coding sequence, the targeting sites for certain CRISPR-Cas are greatly restricted. To address this, here we developed a GFP tagged polycistronic reporter system to determine the activity of CRISPR-Cas in human cells. Specifically, the system contains the herpes simplex virus thymidine kinase (TK) gene, bacterial neomycin phosphotransferase (Neo) gene, and green fluorescent protein (GFP), named TNG gene, with a coding sequence of 2,577 nt. To investigate its performance, we generated a human cell line harboring the TNG expression cassette at the AAVS1 locus, and then we tested it with different Cas orthologs (SaCas9, St1Cas9, and AsCas12a). Our results demonstrated that using the TNG reporter system greatly expands the targeting site selection (3- to 13-fold) with CRISPR-Cas genome editing. The study therefore reports an additional method for the characterization of CRISPR-Cas technology.

Generation of Double-Muscled Sheep and Goats by CRISPR /Cas9-Mediated Knockout of the Myostatin Gene

The myostatin (MSTN) gene has shown to play a critical role in the regulation of skeletal muscle mass, and the translational inhibition of this gene has shown increased muscle mass, generating what is known as "double-muscling phenotype." Disruption of the MSTN gene expression using the CRISPR/Cas9 genome-editing system has shown improved muscle development and growth rates in livestock species, including sheep and goats. Here, we describe procedures for the generation of MSTN knockout sheep and goats using the microinjection approach of the CRISPR/Cas9 system, including the selection of targeting sgRNAs, the construction of CRISPR/Cas9 targeting vector, the in vitro examination of system efficiency, the in vivo targeting to generate MSTN knockout founders, the genomic and phenotypic characterization of the generated offspring, and the assessment of off-target effects in gene-edited founders through targeted validation of predicted off-target sites, as well as genome-wide off-target analysis by whole-genome sequencing. Editing the MSTN gene using the CRISPR/Cas9 system might be a rapid and promising alternative to promote meat production in livestock.

Rapid and cost-effective screening of CRISPR/Cas9-induced mutants by DNA-guided Argonaute nuclease

Objective

With the widespread application of CRISPR/Cas9 gene editing technology, new methods are needed to screen mutants quickly and effectively. Here, we aimed to develop a simple and cost-effective method to screen CRISPR/Cas9-induced mutants.

Result

We report a novel method to identify CRISPR/Cas9-induced mutants through a DNA-guided Argonaute nuclease derived from the archaeon Pyrococcus furiosus. We demonstrated that the Pyrococcus furiosus Argonaute (PfAgo)-based method could distinguish among biallelic mutants, monoallelic mutants and wild type (WT). Furthermore, this method was able to identify 1 bp indel mutations.

Conclusion

The PfAgo-based method is simple to implement and can be applied to screen biallelic mutants and mosaic mutants generated by CRISPR-Cas9 or other kinds of gene editing tools.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10529-021-03177-z.

CRISPR/Cas12a-mediated CHO genome engineering can be effectively integrated at multiple stages of the cell line generation process for bioproduction

Most biopharmaceuticals produced today are generated using Chinese hamster ovary (CHO) cells, therefore significant attention is focused on methods to improve CHO cell productivity and product quality. The discovery of gene-editing tools, such as CRISPR/Cas9, offers new opportunities to improve CHO cell bioproduction through cell line engineering. Recently an additional CRISPR-associated protein, Cas12a (Cpf1), was shown to be effective for gene editing in eukaryotic cells, including CHO. In this study, we demonstrate the successful application of CRISPR/Cas12a for the generation of clonally derived CHO knockout (KO) cell lines with improved product quality attributes. While we found Cas12a efficiency to be highly dependent on the targeting RNA used, we were able to generate CHO KO cell lines using small screens of only 96-320 clonally derived cell lines. Additionally, we present a novel bulk culture analysis approach that can be used to quickly assess CRISPR RNA efficiency and determine ideal screen sizes for generating genetic KO cell lines. Most critically, we find that Cas12a can be directly integrated into the cell line generation process through cotransfection with no negative impact on titer or screen size. Overall, our results show CRISPR/Cas12a to be an efficient and effective CHO genome editing tool.

In Vivo Analysis of Human Immune Responses in Immunodeficient Rats

Supplemental Digital Content is available in the text.

Background.

Humanized immune system immunodeficient mice have been extremely useful for the in vivo analyses of immune responses in a variety of models, including organ transplantation and graft versus host disease (GVHD) but they have limitations. Rat models are interesting complementary alternatives presenting advantages over mice, such as their size and their active complement compartment. Immunodeficient rats have been generated but human immune responses have not yet been described.

Methods.

We generated immunodeficient Rat Rag−/− Gamma chain−/− human signal regulatory protein alpha-positive (RRGS) rats combining Rag1 and Il2rg deficiency with the expression of human signal regulatory protein alpha, a negative regulator of macrophage phagocytosis allowing repression of rat macrophages by human CD47-positive cells. We then immune humanized RRGS animals with human peripheral blood mononuclear cells (hPBMCs) to set up a human acute GVHD model. Treatment of GVHD was done with a new porcine antihuman lymphocyte serum active through complement-dependent cytotoxicity. We also established a tumor xenograft rejection model in these hPBMCs immune system RRGS animals by subcutaneous implantation of a human tumor cell line.

Results.

RRGS animals receiving hPBMCs showed robust and reproducible reconstitution, mainly by T and B cells. A dose-dependent acute GVHD process was observed with progressive weight loss, tissue damage, and death censoring. Antihuman lymphocyte serum (L1S1) antibody completely prevented acute GVHD. In the human tumor xenograft model, detectable tumors were rejected upon hPBMCs injection.

Conclusions.

hPBMC can be implanted in RRGS animals and elicit acute GVHD or rejection of human tumor cells and these are useful models to test new immunotherapies.

Otoferlin gene editing in sheep via CRISPR-assisted ssODN-mediated Homology Directed Repair

Different mutations of the OTOF gene, encoding for otoferlin protein expressed in the cochlear inner hair cells, induces a form of deafness that is the major cause of nonsyndromic recessive auditory neuropathy spectrum disorder in humans. We report the generation of the first large animal model of OTOF mutations using the CRISPR system associated with different Cas9 components (mRNA or protein) assisted by single strand oligodeoxynucleotides (ssODN) to induce homology-directed repair (HDR). Zygote microinjection was performed with two sgRNA targeting exon 5 and 6 associated to Cas9 mRNA or protein (RNP) at different concentrations in a mix with an ssODN template targeting HDR in exon 5 containing two STOP sequences. A total of 73 lambs were born, 13 showing indel mutations (17.8%), 8 of which (61.5%) had knock-in mutations by HDR. Higher concentrations of Cas9-RNP induced targeted mutations more effectively, but negatively affected embryo survival and pregnancy rate. This study reports by the first time the generation of OTOF disrupted sheep, which may allow better understanding and development of new therapies for human deafness related to genetic disorders. These results support the use of CRISPR/Cas system assisted by ssODN as an effective tool for gene editing in livestock.

Characterization of two rat models of cystic fibrosis-KO and F508del CFTR-Generated by Crispr-Cas9

BACKGROUND

Genetically engineered animals are essential for gaining a proper understanding of the disease mechanisms of cystic fibrosis (CF). The rat is a relevant laboratory model for CF because of its zootechnical capacity, size, and airway characteristics, including the presence of submucosal glands.

METHODS

We describe the generation of a CF rat model (F508del) homozygous for the p.Phe508del mutation in the transmembrane conductance regulator (Cftr) gene. This model was compared to new Cftr -/- rats (CFTR KO). Target organs in CF were examined by histological staining of tissue sections and tooth enamel was quantified by micro-computed tomography. The activity of CFTR was evaluated by nasal potential difference (NPD) and short-circuit current measurements. The effect of VX-809 and VX-770 was analyzed on nasal epithelial primary cell cultures from F508del rats.

RESULTS

Both newborn F508del and Knock out (KO) animals developed intestinal obstruction that could be partly compensated by special diet combined with an osmotic laxative. The two rat models exhibited CF phenotypic anomalies such as vas deferens agenesis and tooth enamel defects. Histology of the intestine, pancreas, liver, and lungs was normal. Absence of CFTR function in KO rats was confirmed ex vivo by short-circuit current measurements on colon mucosae and in vivo by NPD, whereas residual CFTR activity was observed in F508del rats. Exposure of F508del CFTR nasal primary cultures to a combination of VX-809 and VX-770 improved CFTR-mediated Cl- transport.

CONCLUSIONS

The F508del rats reproduce the phenotypes observed in CFTR KO animals and represent a novel resource to advance the development of CF therapeutics.

CtIP fusion to Cas9 enhances transgene integration by homology-dependent repair

In genome editing with CRISPR-Cas9, transgene integration often remains challenging. Here, we present an approach for increasing the efficiency of transgene integration by homology-dependent repair (HDR). CtIP, a key protein in early steps of homologous recombination, is fused to Cas9 and stimulates transgene integration by HDR at the human AAVS1 safe harbor locus. A minimal N-terminal fragment of CtIP, designated HE for HDR enhancer, is sufficient to stimulate HDR and this depends on CDK phosphorylation sites and the multimerization domain essential for CtIP activity in homologous recombination. HDR stimulation by Cas9-HE, however, depends on the guide RNA used, a limitation that may be overcome by testing multiple guides to the locus of interest. The Cas9-HE fusion is simple to use and allows obtaining twofold or more efficient transgene integration than that with Cas9 in several experimental systems, including human cell lines, iPS cells, and rat zygotes.

Multiplex CRISPR/Cas9 system impairs HCMV replication by excising an essential viral gene

Anti-HCMV treatments used in immunosuppressed patients reduce viral replication, but resistant viral strains can emerge. Moreover, these drugs do not target latently infected cells. We designed two anti-viral CRISPR/Cas9 strategies to target the UL122/123 gene, a key regulator of lytic replication and reactivation from latency. The singleplex strategy contains one gRNA to target the start codon. The multiplex strategy contains three gRNAs to excise the complete UL122/123 gene. Primary fibroblasts and U-251 MG cells were transduced with lentiviral vectors encoding Cas9 and one or three gRNAs. Both strategies induced mutations in the target gene and a concomitant reduction of immediate early (IE) protein expression in primary fibroblasts. Further detailed analysis in U-251 MG cells showed that the singleplex strategy induced 50% of indels in the viral genome, leading to a reduction in IE protein expression. The multiplex strategy excised the IE gene in 90% of all viral genomes and thus led to the inhibition of IE protein expression. Consequently, viral genome replication and late protein expression were reduced by 90%. Finally, the production of new viral particles was nearly abrogated. In conclusion, the multiplex anti-UL122/123 CRISPR/Cas9 system can target the viral genome efficiently enough to significantly prevent viral replication.

A simple and efficient method for CRISPR/Cas9-induced mutant screening

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system provides a technological breakthrough in mutant generation. Several methods such as the polymerase chain reaction (PCR)/restriction enzyme (RE) assay, T7 endonuclease I (T7EI) assay, Surveyor nuclease assay, PAGE-based genotyping assay, and high-resolution melting (HRM) analysis-based assay have been developed for screening CRISPR/Cas9-induced mutants. However, these methods are time- and labour-intensive and may also be sequence-limited or require very expensive equipment. Here, we described a cost-effective and sensitive screening technique based on conventional PCR, annealing at critical temperature PCR (ACT-PCR), for identifying mutants. ACT-PCR requires only a single PCR step followed by agarose gel electrophoresis. We demonstrated that ACT-PCR accurately distinguished CRISPR/Cas9-induced mutants from wild type in both rice and zebrafish. Moreover, the method can be adapted for accurately determining mutation frequency in cultured cells. The simplicity of ACT-PCR makes it particularly suitable for rapid, large-scale screening of CRISPR/Cas9-induced mutants in both plants and animals.

Comparative Analysis of piggyBac, CRISPR/Cas9 and TALEN Mediated BAC Transgenesis in the Zygote for the Generation of Humanized SIRPA Rats

BAC transgenic mammalian systems offer an important platform for recapitulating human gene expression and disease modeling. While the larger body mass, and greater genetic and physiologic similarity to humans render rats well suited for reproducing human immune diseases and evaluating therapeutic strategies, difficulties of generating BAC transgenic rats have hindered progress. Thus, an efficient method for BAC transgenesis in rats would be valuable. Immunodeficient mice carrying a human SIRPA transgene have previously been shown to support improved human cell hematopoiesis. Here, we have generated for the first time, human SIRPA BAC transgenic rats, for which the gene is faithfully expressed, functionally active, and germline transmissible. To do this, human SIRPA BAC was modified with elements to work in coordination with genome engineering technologies-piggyBac, CRISPR/Cas9 or TALEN. Our findings show that piggyBac transposition is a more efficient approach than the classical BAC transgenesis, resulting in complete BAC integration with predictable end sequences, thereby permitting precise assessment of the integration site. Neither CRISPR/Cas9 nor TALEN increased BAC transgenesis. Therefore, an efficient generation of human SIRPA transgenic rats using piggyBac opens opportunities for expansion of humanized transgenic rat models in the future to advance biomedical research and therapeutic applications.