The generation of a tau-V337M point mutation mouse model using gene editing technology can provide an animal model with fast disease progression and more severe symptoms, which facilitate the study of pathogenesis and treatment of Alzheimer's disease (AD). In this study, single guide RNAs (sgRNA) and single-stranded oligonucleotides (ssODN) were designed and synthesized in vitro. The mixture of sgRNA, Cas9 protein and ssODN was microinjected into the zygotes of C57BL/6J mice. After DNA cutting and recombination, the site homologous to human 337 valine (GTG) in exon 11 was mutated into methionine (ATG). In order to improve the efficiency of recombination, a Rad51 protein was added. The female mice mated with the nonvasectomy male mice were used as the surrogates. Subsequently, the 2-cell stage gene edited embryos were transferred into the unilateral oviduct, and the F0 tau-V337M mutation mice were obtained. Higher mutation efficiency could be obtained by adding Rad51 protein. The F0 tau-V337M point mutation mice can pass the mutation on to the F1 generation mice. In conclusion, this study successfully established the first tau-V337M mutation mouse by using Cas9, ssODN and Rad51. These results provide a new method for developing AD mice model which can be used in further research on the pathogenesis and treatment of AD.
Animals ; Male ; Female ; Mice ; Humans ; CRISPR-Cas Systems/genetics* ; RNA, Guide, CRISPR-Cas Systems ; Rad51 Recombinase/genetics* ; Mice, Inbred C57BL ; Disease Models, Animal ; Recombination, Genetic

Current studies have shown that centromere protein F (CENPF) was overexpressed in hepatocellular carcinoma (HCC) and might be involved in the pathogenesis of HCC. Specifically, due to the very large molecular weight (358 kDa) of CENPF full length protein, only CENPF knock-down, but not overexpression models, were applied currently to explore the carcinogenicity of CENPF in HCC. Whether CENPF overexpression is a cause or an effect in HCC remains to be illustrated. We aimed to establish a CENPF overexpression cell model using CRISPR/dCas9 synergistic activation mediator (SAM) system with lentiMPHv2 and lentiSAMv2 vectors to explore the role of CENPF overexpression in HCC. Single guide RNAs (sgRNAs) that specifically identify the transcription initiation site of CENPF gene were synthesized and inserted into the lentiSAMv2 plasmid. Huh-7 and HCCLM3 cells were first transduced with lentiMPHv2 and then selected with hygromycin B. The cells were then transduced with lentiSAMv2 carrying specific sgRNA for CENPF gene, followed by blasticidin S selection. The mRNA and protein detection results of Huh-7 and HCCLM3 cells screened by hygromycin B and blasticidin S showed that the endogenous overexpression of CENPF can be induced by sgRNA1 and sgRNA4, especially by sgRNA4. By using the CRISPR/dCas9 technique, stable cell models with overexpressed CENPF were successfully constructed to explore the role of CENPF in tumorigenesis, which provides a reference for the construction of cell models overexpressing large molecular weight protein.
Humans ; Carcinoma, Hepatocellular/genetics* ; Liver Neoplasms/genetics* ; RNA, Guide, CRISPR-Cas Systems ; Clustered Regularly Interspaced Short Palindromic Repeats ; Hygromycin B

This study aimed to explore the expression changes of VASA gene in sheep testis development and to construct VASA gene knock-in vector to prepare for the study on the differentiation of sheep germ cells in vitro. The testicular tissues of 3-month-old (3M) and 9-month-old (9M) sheep which represent immature and mature stages, respectively, were collected. The differential expression of VASA gene was analyzed by quantitative real-time PCR (qPCR) and Western blotting, and the location of VASA gene was detected by immunohistochemistry. The sgRNA targeting the VASA gene was designed and homologous recombination vectors were constructed by PCR. Subsequently, plasmids were transferred into sheep ear fibroblasts. The VASA gene was activated in combination with CRISPR/dCas9 technology to further verify the efficiency of the vector. The results showed that the expression level of VASA gene increased significantly with the development of sheep testis (P < 0.01), and was mainly located in spermatocytes and round spermatids. The knock-in vector of VASA gene was constructed by CRISPR/Cas9 system, and the Cas9-gRNA vector and pEGFP-PGK puro-VASA vector were transfected into ear fibroblasts. After CRISPR/dCas9 system was activated, ear fibroblasts successfully expressed VASA gene. The results suggest that VASA gene plays a potential function in sheep testicular development and spermatogenesis, and the VASA gene knock-in vector can be constructed in vitro through the CRISPR/Cas9 system. Our results provided effective research tools for further research of germ cell development and differentiation.
Male ; Animals ; Sheep/genetics* ; CRISPR-Cas Systems/genetics* ; Gene Knock-In Techniques ; RNA, Guide, CRISPR-Cas Systems ; Plasmids ; Germ Cells

The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system has been widely used for genome engineering and transcriptional regulation in many different organisms. Current CRISPR-activation (CRISPRa) platforms often require multiple components because of inefficient transcriptional activation. Here, we fused different phase-separation proteins to dCas9-VPR (dCas9-VP64-P65-RTA) and observed robust increases in transcriptional activation efficiency. Notably, human NUP98 (nucleoporin 98) and FUS (fused in sarcoma) IDR domains were best at enhancing dCas9-VPR activity, with dCas9-VPR-FUS IDR (VPRF) outperforming the other CRISPRa systems tested in this study in both activation efficiency and system simplicity. dCas9-VPRF overcomes the target strand bias and widens gRNA designing windows without affecting the off-target effect of dCas9-VPR. These findings demonstrate the feasibility of using phase-separation proteins to assist in the regulation of gene expression and support the broad appeal of the dCas9-VPRF system in basic and clinical applications.
Humans ; Transcriptional Activation ; RNA, Guide, CRISPR-Cas Systems ; Gene Expression Regulation ; CRISPR-Cas Systems/genetics*

Gene editing technology has been a hotspot in the field of biotechnology. CRISPR/Cas systems are efficient gene editing tools because of its specificity, simplicity and flexibility, these features enabled the rapid application of CRISPR/Cas systems in a variety of organisms. Moreover, the combination of transcriptional activator with dead Cas protein can achieve specific regulation of gene expression at the transcription level, which has made important contributions to the development of biotechnology in medical and agriculture. Overexpression of foreign genes is a common method to verify gene function and regulation. However, due to the limitation of vector capacity, it is difficult to achieve overexpression of multiple genes. CRISPR/Cas9 activation system can regulate the expression of multiple genes under the guidance of different guide RNAs to verify gene functions at the regulatory level. This review summarizes the composition of the CRISPR/Cas9 activation system and different activation strategies, and summarizes solutions for excessive activation. It may facilitate the application of CRISPR/Cas9 activation system in genetic improvement of cotton and herbicide resistance research.
Biotechnology ; CRISPR-Cas Systems/genetics* ; Gene Editing ; Phenotype ; RNA, Guide, Kinetoplastida/metabolism*

As a new CRISPR/Cas-derived genome engineering technology, base editing combines the target specificity of CRISPR/Cas and the catalytic activity of nucleobase deaminase to install point mutations at target loci without generating DSBs, requiring exogenous template, or depending on homologous recombination. Recently, researchers have developed a variety of base editing tools in the important industrial strain Corynebacterium glutamicum, and achieved simultaneous editing of two and three genes. However, the multiplex base editing based on CRISPR/Cas9 is still limited by the complexity of multiple sgRNAs, interference of repeated sequence and difficulty of target loci replacement. In this study, multiplex base editing in C. glutamicum was optimized by the following strategies. Firstly, the multiple sgRNA expression cassettes based on individual promoters/terminators was optimized. The target loci can be introduced and replaced rapidly by using a template plasmid and Golden Gate method, which also avoids the interference of repeated sequence. Although the multiple sgRNAs structure is still complicated, the editing efficiency of this strategy is the highest. Then, the multiple gRNA expression cassettes based on Type Ⅱ CRISPR crRNA arrays and tRNA processing were developed. The two strategies only require one single promoter and terminator, and greatly simplify the structure of the expression cassette. Although the editing efficiency has decreased, both methods are still applicable. Taken together, this study provides a powerful addition to the genome editing toolbox of C. glutamicum and facilitates genetic modification of this strain.
CRISPR-Cas Systems/genetics* ; Corynebacterium glutamicum/metabolism* ; Gene Editing ; Plasmids ; RNA, Guide/metabolism*

To investigate the cellular target selectivity of small molecules targeting thioredoxin reductase 1, we reported the construction and functional research of a stable TrxR1 gene (encode thioredoxin reductase 1) knockout HCT-116 cell line. We designed and selected TrxR1 knockout sites according to the TrxR1 gene sequence and CRISPR/Cas9 target designing principles. SgRNA oligos based on the selected TrxR1 knockout sites were obtained. Next, we constructed knockout plasmid by cloning the sgRNA into the pCasCMV-Puro-U6 vector. After transfection of the plasmid into HCT-116 cells, TrxR1 knockout HCT-116 cells were selected using puromycin resistance. The TrxR1 knockout efficiency was identified and verified by DNA sequencing, immunoblotting, TRFS-green fluorescent probe, and cellular TrxR1 enzyme activity detection. Finally, the correlation between TrxR1 expression and cellular effects of drugs specifically targeting TrxR1 was investigated by CCK-8 assay. The results demonstrated that the knockout plasmid expressing the sgRNA effectively knocked-out TrxR1 gene within HCT-116 cells, and no expression of TrxR1 protein could be observed in stable TrxR1 knockout HCT-116 (HCT116-TrxR1-KO) cells. The TrxR1-targeting inhibitor auranofin did not show any inhibitory activity against either cellular TrxR1 enzyme activity or cell proliferation. Based on these results, we conclude that a stable TrxR1 gene knockout HCT-116 cell line was obtained through CRISPR/Cas9 techniques, which may facilitate investigating the role of TrxR1 in various diseases.
CRISPR-Cas Systems/genetics* ; Gene Editing ; Gene Knockout Techniques ; HCT116 Cells ; Humans ; RNA, Guide/metabolism*

OBJECTIVE: Two sgRNAs transfected FLT3-ITD⁺AML cell line MV411 with different binding sites were introduced into CRISPR/cas9 to obtain MV411 cells with miR-155 gene knockout. To compare the efficiency of miR-155 gene knockout by single and double sgRNA transfection and their effects on cell phenotypes. METHODS: The lentiviral vectors were generated containing either single sgRNA or dual sgRNAs and packaged into lentivirus particles. PCR was conducted to measure gene editing efficiency, and miR-155 expression was evaluated by qPCR. CCK-8 assay was used to evaluate the cell proliferation, and calculate drug sensitivity of cells to adriamycin and quizartinib. Annexin V-APC/7-AAD staining was used to label cell apoptosis induced by adriamycin and quizartinib. RESULTS: In the dual sgRNAs transfected cells, a cleavage band could be observed, meaning the success of gene editing. Compared with the single sgRNA transfected MV411 cells, the expression level of mature miR-155-5p was lower in the dual sgRNA transfected cells. And, dual sgRNA transfected MV411 were more sensitive to adriamycin and quizartinib with lower IC₅₀ and higher apoptosis rate. CONCLUSION The inhibition rate of miR-155 gene expression transfected by dual sgRNA is higher than that by single sgRNA. Dual sgRNA transfection can inhibit cell proliferation, reverse drug resistance, and induce apoptosis more significantly. Compared with single sgRNA transfection, dual sgRNA transfection is a highly efficient gene editing scheme.
CRISPR-Cas Systems ; Doxorubicin/pharmacology* ; Drug Resistance ; Gene Editing ; Humans ; Leukemia, Myeloid, Acute/genetics* ; MicroRNAs/genetics* ; RNA, Guide/genetics* ; fms-Like Tyrosine Kinase 3/genetics*

OBJECTIVE: To construct a mouse model of Glanzmann's thrombasthenia (GT) with ITGA2B c.2659 C>T (p.Q887X) nonsense mutation by CRISPR/Cas9 technology, and then further explore the expression and function of glycoprotein αIIbβ3 on the surface of platelet membrane. METHODS: The donor oligonucleotide and gRNA vector were designed and synthesized according to the ITGA2B gene sequence. The gRNA and Cas9 mRNA were injected into fertilized eggs with donor oligonucleotide and then sent back to the oviduct of surrogate mouse. Positive F0 mice were confirmed by PCR genotyping and sequence analysis after birth. The F1 generation of heterozygous GT mice were obtained by PCR and sequencing from F0 bred with WT mice, and then homozygous GT mice and WT mice were obtained by mating with each other. The phenotype of the model was then further verified by detecting tail hemorrhage time, saphenous vein bleeding time, platelet aggregation, expression and function of αIIbβ3 on the surface of platelet. RESULTS: The bleeding time of GT mice was significantly longer than that of WT mice (P<0.01). Induced by collagen, thrombin, and adenosine diphosphate (ADP), platelet aggregation in GT mice was significantly inhibited (P<0.01, P<0.01, P<0.05). Flow cytometry analysis showed that the expression of αIIbβ3 on the platelet surface of GT mice decreased significantly compared with WT mice (P<0.01), and binding amounts of activated platelets to fibrinogen were significantly reduced after thrombin stimulation (P<0.01). The spreading area of platelet on fibrinogen in GT mice was significantly smaller than that in WT mice (P<0.05). CONCLUSION A GT mouse model with ITGA2B c.2659 C>T (p.Q887X) nonsense mutation has been established successfully by CRISPR/Cas9 technology. The aggregation function of platelet in this model is defective, which is consistent with GT performance.
Animals ; CRISPR-Cas Systems ; Codon, Nonsense ; Disease Models, Animal ; Fibrinogen/genetics* ; Humans ; Integrin alpha2/genetics* ; Mice ; Oligonucleotides ; Platelet Glycoprotein GPIIb-IIIa Complex/genetics* ; RNA, Guide ; Thrombasthenia/genetics* ; Thrombin/genetics*

Generation of mutants with clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) is commonly carried out in fish species by co-injecting a mixture of Cas9 messenger RNA (mRNA) or protein and transcribed guide RNA (gRNA). However, the appropriate expression system to produce functional gRNAs in fish embryos and cells is rarely present. In this study, we employed a poly-transfer RNA (tRNA)-gRNA (PTG) system driven by cytomegalovirus (CMV) promoter to target the medaka (Oryzias latipes) endogenous gene tyrosinase(tyr) or paired box 6.1 (pax6.1) and illustrated its function in a medaka cell line and embryos. The PTG system was combined with the CRISPR/Cas9 system under high levels of promoter to successfully induce gene editing in medaka. This is a valuable step forward in potential application of the CRISPR/Cas9 system in medaka and other teleosts.
Animals ; CRISPR-Cas Systems ; Cell Line ; Gene Editing ; Oryzias/genetics* ; RNA, Guide/genetics* ; RNA, Transfer/genetics*