ABSTRACT
@#ObjectiveTo design and construct CRISPR/Cas9 gene editing system targeting Tsc1 and Tsc2 genes,and verify the effectiveness of gene editing at cellular level.MethodsThree sgRNA guide sequences were designed for mouse Tsc1 and Tsc2 genes respectively. The sgRNA expression vector was constructed and co-transfected with the Cas9 expression plasmid into mouse N2a cells. After the positive cells were obtained through drug screening,the DNA fragments at the targeting site were amplified by PCR,and the targeting efficiency was verified by TA clone sequencing.ResultsThe five targets of Tsc1-M-sgRNA2 and Tsc1-M-sgRNA3 of Tsc1 gene and Tsc2-M-sgRNA1,Tsc2-M-sgRNA2 and Tsc2-M-sgRNA3 of Tsc2 gene were all edited,and the editing efficiency was 40%,80%,30%,30% and 20%,respectively.ConclusionA CRISPR-Cas9 gene editing system with editing efficiency targeting mouse Tsc1 and Tsc2 genes was successfully constructed.
ABSTRACT
@#Objective To knockout interferon alpha/beta receptor subunit 1(IFNAR1) gene in human colorectal adenocarcinoma cells Caco-2 using clustered regularly interspaced short palinmic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)system to construct IFNAR1 knockout Caco-2 cell line.Methods The single guide RNA(sgRNA)sequence was designed to specifically recognize the exon region of IFNAR1 gene using CRISPR/Cas9 technology,and the LentiCRISPRv2-IFNAR1-sgRNA recombinant plasmid was constructed.Caco-2 cells were infected with the plasmid packaged by lentivirus and screened by puromycin resistance.The obtained monoclonal cell lines were cultured by limited dilution method,which were verified for the effect of IFNAR1 gene knockout by target gene sequencing and Western blot,and detected for the mRNA levels of CXC chemokine ligand 10(CXCL10)and interferon-stimulatd gene 20(ISG20)in IFNAR1knockout cells by adding exogenous IFNβ.Results Sequencing results of plasmid LentiCRISPRv2-IFNAR1-sgRNA showed that the insertion sites were all located at the sticky end of BsmBⅠenzyme digestion.Two IFNAR1 knockout monoclonal cell lines were obtained.The sequencing results showed that Caco-2-IFNAR1-KO1 had 5 bp deletion in the sixth exon of IFNAR1,and Caco-2-IFNAR1-KO2 had 18 bp deletion and 1 bp insertion in the seventh exon.Compared with wild-type Caco-2 cells,Caco-2-IFNAR1-KO1 and Caco-2-IFNAR1-KO2 cells showed no expression of IFNAR1 protein.Compared with no IFNβ stimulation,the mRNA levels of CXCL10 gene(t = 0.566 and 1.268 respectively,P>0.05)and ISG20 gene(t =1.522 and 1.733 respectively,P>0.05)in Caco-2-IFNAR1-KO1 and Caco-2-IFNAR1-KO2 cells stimulated by 50 ng/mL IFNβ showed no significant increase.While compared with those of wild-type Caco-2 cells,the mRNA levels of CXCL10gene(t = 6.763 and 6.777 respectively,P<0.05)and ISG20 gene(t = 5.664 and 5.65 respectively,P<0.05)in Caco-2-IFNAR1-KO1 and Caco-2-IFNAR1-KO2 cells decreased significantly under the stimulation of 50 ng/mL exogenous IFNβ.Conclusion Caco-2 cell line with IFNAR1 knockout was successfully constructed by using CRISPR/Cas9 technology,and the downstream molecules activated by IFNAR(interferon alpha/beta receptor)in this cell line were obviously inhibited,which provided a powerful tool for further exploration of the innate immune response and replication packaging mechanism of Caco-2 cells after virus infection.
ABSTRACT
Both natural ginsenoside F2 and unnatural ginsenoside 3β,20S-Di-O-Glc-DM were reported to exhibit anti-tumor activity. Traditional approaches for producing them rely on direct extraction from Panax ginseng, enzymatic catalysis or chemical synthesis, all of which result in low yield and high cost. Metabolic engineering of microbes has been recognized as a green and sustainable biotechnology to produce natural and unnatural products. Hence we engineered the complete biosynthetic pathways of F2 and 3β,20S-Di-O-Glc-DM in Saccharomyces cerevisiae via the CRISPR/Cas9 system. The titers of F2 and 3β,20S-Di-O-Glc-DM were increased from 1.2 to 21.0 mg/L and from 82.0 to 346.1 mg/L at shake flask level, respectively, by multistep metabolic engineering strategies. Additionally, pharmacological evaluation showed that both F2 and 3β,20S-Di-O-Glc-DM exhibited anti-pancreatic cancer activity and the activity of 3β,20S-Di-O-Glc-DM was even better. Furthermore, the titer of 3β,20S-Di-O-Glc-DM reached 2.6 g/L by fed-batch fermentation in a 3 L bioreactor. To our knowledge, this is the first report on demonstrating the anti-pancreatic cancer activity of F2 and 3β,20S-Di-O-Glc-DM, and achieving their de novo biosynthesis by the engineered yeasts. Our work presents an alternative approach to produce F2 and 3β,20S-Di-O-Glc-DM from renewable biomass, which lays a foundation for drug research and development.
ABSTRACT
Carrimycin (CAM) is a new antibiotics with isovalerylspiramycins (ISP) as its major components. It is produced by Streptomyces spiramyceticus integrated with a heterogenous 4″-O-isovaleryltransferase gene (ist). However, the present CAM producing strain carries two resistant gene markers, which makes it difficult for further genetic manipulation. In addition, isovalerylation of spiramycin (SP) could be of low efficiency as the ist gene is located far from the SP biosynthesis gene cluster. In this study, ist and its positive regulatory gene acyB2 were inserted into the downstream of orf54 gene neighboring to SP biosynthetic gene cluster in Streptomyces spiramyceticus 1941 by using the CRISPR-Cas9 technique. Two new markerless CAM producing strains, 54IA-1 and 54IA-2, were obtained from the homologous recombination and plasmid drop-out. Interestingly, the yield of ISP in strain 54IA-2 was much higher than that in strain 54IA-1. Quantitative real-time PCR assay showed that the ist, acyB2 and some genes associated with SP biosynthesis exhibited higher expression levels in strain 54IA-2. Subsequently, strain 54IA-2 was subjected to rifampicin (RFP) resistance selection for obtaining high-yield CAM mutants by ribosome engineering. The yield of ISP in mutants resistant to 40 μg/mL RFP increased significantly, with the highest up to 842.9 μg/mL, which was about 6 times higher than that of strain 54IA-2. Analysis of the sequences of the rpoB gene of these 7 mutants revealed that the serine at position 576 was mutated to alanine existed in each sequenced mutant. Among the mutants carrying other missense mutations, strain RFP40-6-8 which carries a mutation of glutamine (424) to leucine showed the highest yield of ISP. In conclusion, two markerless novel CAM producing strains, 54IA-1 and 54IA-2, were successfully developed by using CRISPR-Cas9 technique. Furthermore, a novel CAM high-yielding strain RFP40-6-8 was obtained through ribosome engineering. This study thus demonstrated a useful combinatory approach for improving the production of CAM.
Subject(s)
CRISPR-Cas Systems/genetics , Genetic Engineering , Ribosomes , Spiramycin , Streptomyces/geneticsABSTRACT
The introduction of the mevalonate pathway (MVA pathway) in recombinant Escherichia coli can improve the synthesis of terpenoids. But the imbalance expression of MVA pathway genes and accumulation of intermediates inhibit cell growth and terpenoids production. In this study, each gene of MVA pathway and key genes of lycopene synthesis pathway were cloned in plasmid to express in the recombinant E. coli LYC103 with optimizing the expression of the key genes of the 2-methyl-D-erythritol-4-phosphate pathway (MEP pathway), chromosome recombinant MVA pathway and the lycopene synthesis pathway. The results showed that the overexpression of ispA, crtE, mvaK1, idi and mvaD genes did not affect the cell growth, while lycopene production increased by 13.5%, 16.5%, 17.95%, 33.7% and 61.1% respectively, indicating that these genes may be the rate-limiting steps for the synthesis of lycopene. mvaK1, mvaK2, mvaD of MVA pathway were the rate-limiting steps and were in an operon. The mvaK1, mvaK2, mvaD operon was regulated by mRS (mRNA stabilizing region) library in front of mvaK1, obtaining strain LYC104. Lycopene yield of LYC104 was doubled and cell growth was increased by 32% compared with the control strain LYC103. CRISPR-cas9 technology was used to integrate idi into chromosome at lacZ site to obtain LYC105 strain. Cell growth of LYC105 was increased by 147% and lycopene yield was increased by 2.28 times compared with that of LYC103. In this study, each gene of lycopene synthesis pathway was expressed in plasmid to certify the rate-limiting gene based on the complete MVA pathway on the chromosome. Then the rate-limiting gene was integrated in chromosome with homologous recombination to release the rate-limiting, which providing a new strategy for the construction of high-yield strains for metabolic engineering.
ABSTRACT
@#Based on the three delivery forms of CRISPR/Cas9 system at the levels of DNA, RNA and protein, this paper mainly approaches the development and new strategies of CRISPR/Cas9 delivery systems, as well as their application in the biomedical field and the clinical treatment of gene-related diseases. By summarizing and elaborating the CRISPR/Cas9 system delivery and gene therapy strategy, new ideas are provided for the discovery of innovative drugs and the development of gene therapy.
ABSTRACT
Isoprenoids are all derived from two five-carbon building blocks called isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), which are synthesized either by the mevalonate (MVA) pathway or 2-C-methyld-D-erythritol-4-phosphate (MEP) pathway. In this study, the MVA pathway genes were integrated into the chromosome of LYC101, in which the expression of key genes in the MEP synthesis pathway and lycopene synthesis pathway were optimized by artificial regulatory parts, to further improve the production of isoprenoids in Escherichia coli. The plasmids pALV23 and pALV145 were screened from a plasmid library that constructed by using the RBS library to link the genes of the MVA pathway, which greatly increased the production of β-carotene. The effects of plasmids pALV23 and pALV145 on the lycopene production in low and high lycopene production strain, LYC001 and LYC101, were compared, respectively. The production of lycopene was increased by plasmids pALV23 and pALV145 in both strains. In high lycopene production strain LYC101, pALV23 produced more lycopene than pALV145. Then, the MVA gene together of promoter of pALV23 was integrated into the chromosome of LYC101 at poxB site using method of homologous recombination helped by CRISPR-Cas9 system, resulted in genetically stable strain, LYC102. The yield of lycopene of LYC102 was 40.9 mg/g DCW, 1.19-folds higher than that of LYC101, and 20% more than that of LYC101 with pALV23. Simultaneous expression of MVA pathway and MEP pathway in recombinant E. coli can effectively increase the yield of terpenoids. In this study, a plasmid-free, genetically stable, high-yielding lycopene strain was constructed, which could be used for industrialization. Also, the platform strain can be used for the synthesis of other terpenoids.
Subject(s)
Chromosomes, Bacterial , Escherichia coli , Lycopene , Mevalonic Acid , beta CaroteneABSTRACT
Isovalerylspiramycin (ISP)Ⅰ, as a major component of bitespiramycin (BT), exhibits similar antimicrobial activities with BT and has advantages in quality control and dosage forms. It has been under preclinical studies. The existing ISPⅠ producing strain, undergoing three genetic modifications, carries two resistant gene markers. Thus, it is hard for further genetic manipulation. It is a time-consuming and unsuccessful work to construct a new ISPⅠ strain without resistant gene marker by means of the classical homologous recombination in our preliminary experiments. Fortunately, construction of the markerless ISPⅠ strain, in which the bsm4 (responsible for acylation at 3 of spiramycin) gene was replaced by the Isovaleryltansferase gene (ist) under control of the constitutive promoter ermEp*, was efficiently achieved by using the CRISPR-Cas9 gene editing system. The mutant of bsm4 deletion can only produce SPⅠ. Isovaleryltransferase coded by ist catalyzes the isovalerylation of the SPⅠat C-4" hydroxyl group to produce ISPⅠ. As anticipated, ISPⅠ was the sole ISP component of the resultant strain (ΔEI) when detected by HPLC and mass spectrometry. The ΔEI mutant is suitable for further genetic engineering to obtain improved strains by reusing CRISPR-Cas9 system.
Subject(s)
CRISPR-Cas Systems , Gene Editing , Genetic Engineering , Homologous RecombinationABSTRACT
@#Objective: : To explore the effect of PD-1 gene knockout by CRISPR/Cas9 system on the proliferation and IFN-γ secretion in human T cells. Methods: : The sequence of sgRNA targeting PD-1 was designed. The PD-1-sgRNA and Cas9 mRNA were synthesized by T7 RNApolymerase in vitro, and then the mixture of PD-1-sgRNAand Cas9 mRNAwas delivered into activated T cells by nucleofection. The efficiency of gene knockout was confirmed by sequencing. The phenotypes of T lymphocytes and the expression of PD-1 after gene knockout were analyzed by Flow cytometry. The proliferation of T lymphocytes was calculated by trypan blue counting. The level of IFN-γ secreted by T lymphocytes was detected by ELISA. Results： ：PD-1-sgRNA and Cas9 mRNA were successfully synthesized in vitro and delivered into T cells by nucleofection. Sequencing technology confirmed that the PD-1 gene sequence was edited and the editing efficiency was 58.3%. The expression of PD-1 on T lymphocyte surface was down-regulated successfully by CRISPR/Cas9 system [(9.6±1.85)% vs (16.2±2.05)%, P<0.05]. The knockout of PD-1 gene did not affect the proliferation and phenotype of T lymphocytes(P<0.05); However, compared with the control group, the level of IFN-γ secreted by T lymphocytes in the PD-1sgRNA group was significantly increased (P<0.01). Conclusion: : CRISPR/Cas9 system can successfully ablate PD-1 gene in human T lymphocytes, which could block the negative regulation of PD-1／PD-L1 and further promote the IFN-γ secretion in T cells.
ABSTRACT
In the 1960s, scientists first raised the idea of curing genetic diseases using gene therapy. This new conceptual strategy aimed to achieve a much longer therapeutic effect by introducing exogenous genetic materials into the patients. After more than five decades of ups and downs, gene therapy has been brought into a new era by those milestone breakthroughs in the 21st century. Here we reviewed and summarized the history and breakthroughs of gene therapy, including some critical clinical trials, approved drugs, and emerging gene editing techniques. We believe that with their unique advantages over traditional therapies, more gene therapies will become practical approaches to genetic diseases and benefit the entire human race.
Subject(s)
Humans , CRISPR-Cas Systems , Gene Editing , Genetic TherapyABSTRACT
CRISPR/Cas9 system, consisting of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins, is a prokaryotic immune system that confers resistance to foreign genetic elements such as those present within plasmids and phages. A simple version of the CRISPR/Cas system, type Ⅱ CRISPR, has been modified to edit genomes. By delivering the Cas9 nuclease together with a synthetic guide RNA (sgRNA) into cells, genome can be edited at desired loci site. CRISPR/Cas genome editing techniques have been widely implemented in various species and research areas. In this review, we summarize the several applications of CRISPR/Cas9 in the field of drug discovery and development, which include target gene screening and editing, drug target screening and validation, generation of animal models and treatment of genetic disease, etc. The defects and improvements of CRISPR/Cas9 technology is discussed as well.
ABSTRACT
The incidence and mortality of AIDS have been decreasing after the adoption of combined antiretroviral therapy strategy in the world,then AIDS has become a manageable chronic infectious disease.But HIV/AIDS continues to be a major global public health problem since it is restricted by a variety of factors.The major reason for the persistence of HIV/AIDS is the inability of existing treatments to clear or eradicate the multiple HIV reservoirs that exist in the human body.To suppress the virus replication and rebound,HIV/AIDS patients must take life-long antiviral medications.A few years ago,the clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9)system has been developed as a simple,fast and easy to operate gene-editing technique.Several studies in HIV infected cells and/or in animal models have shown that the system has the potential to eliminate or disrupt HIV-integrated genome or HIV-infected cells from multiple HIV reservoirs,which may result in the complete cure of HIV/AIDS.This paper analyzes the results of CRISPR/CAS9 in the elimination of latent HIV,and discusses the possible problems and trends.
ABSTRACT
Objective To investigate the role of non-small cell lung cancer metastasis-related Trim72 gene in hepatocellular carcinoma (HCC) using clustered regularly interspaced short palindromic repeats (CRISPR) Cas9 system.Methods Hepa1-6 (Cas9) HCC cells were established with stable expression of Cas9 protein,and then specific gene knockout was performed using sgRNA targeting Trim72 gene.After obtaining the Hepa1-6 (Trim72-KO) cells,the metastasis and invasion abilities of the cells were evaluated by in vitro Transwell assay and in vivo subcutaneous lung metastasis examination.Results Hepa1-6 (Trim72-KO) cell line was successfully established by the CRISPR-Cas9 system.Transwell assay indicated that the mobility of Hepa1-6 (Trim72-KO) cells was increased compared to the control cells.Transwell assay indicated that the metastasis and invasion of Hepa1-6 (Cas9) HCC cells were enhanced after the knockout of Trim72 gene.The pathological examination of lung metastasis of subcutaneous tumor in vivo showed that the subcutaneously metastatic ability of Hepa1-6 (Trim72-KO) cells (the experimental group) was significantly stronger than Hepa1-6 (Cas9) cells (the control troup) that were not transferred to the corresponding sgRNA.Conclusions The trim72 gene knocked-out HCC cells were obtained by CRISPR-Cas9 system,which showed stronger metastasis and invasion abilities than the control cells.It is suggested that Trim72 gene may play an important role in the invasion and metastasis of HCC,and Trim 72 gene is expected to be a potential target for gene therapy of liver cancer.
ABSTRACT
Objective To construct mitochondrial antiviral-signaling protein ( MAVS ) knockout ZR-751 breast neoplasms cells using CRISPR/Cas9 genome engineering technology , and study the effect of MAVS on cell proliferation . Methods Small guide RNA ( sgRNA ) was designed by targeting the first exon of MAVS gene and the pX 459-sgRNA recombinant eukaryotic expressional plasmid was constructed .Puromycin was used to screen monoclonal cells which stably knocked out MAVS gene .The knockout effect was measured by Western blotting .Cellular proliferation rates were detected by colony-forming assay when MAVS gene was knockout .The MTS assay was designed to detect the effect of MAVS on cell proliferation under DFX stimulus .Results The result of Western blotting suggested that no MAVS protein was detected in the MAVS gene knockout stable ZR-751 cells,showing that MAVS gene was knocked out completely .Proliferation became faster when MAVS was knocked out .MAVS promoted cell death under DFX stimulus .Conclusion The MAVS knockout ZR-751 stable cells have been constructed using CRISPR/Cas9 system.The preliminary experimental results show that MAVS inhibits breast cancer cell proliferation , which will facilitate studies on the function of MAVS in tumors in the future .
ABSTRACT
Objective To construct mitochondrial antiviral-signaling protein ( MAVS ) knockout ZR-751 breast neoplasms cells using CRISPR/Cas9 genome engineering technology , and study the effect of MAVS on cell proliferation . Methods Small guide RNA ( sgRNA ) was designed by targeting the first exon of MAVS gene and the pX 459-sgRNA recombinant eukaryotic expressional plasmid was constructed .Puromycin was used to screen monoclonal cells which stably knocked out MAVS gene .The knockout effect was measured by Western blotting .Cellular proliferation rates were detected by colony-forming assay when MAVS gene was knockout .The MTS assay was designed to detect the effect of MAVS on cell proliferation under DFX stimulus .Results The result of Western blotting suggested that no MAVS protein was detected in the MAVS gene knockout stable ZR-751 cells,showing that MAVS gene was knocked out completely .Proliferation became faster when MAVS was knocked out .MAVS promoted cell death under DFX stimulus .Conclusion The MAVS knockout ZR-751 stable cells have been constructed using CRISPR/Cas9 system.The preliminary experimental results show that MAVS inhibits breast cancer cell proliferation , which will facilitate studies on the function of MAVS in tumors in the future .
ABSTRACT
Our previous study demonstrated that human KIAA0100 gene is a novel acute monocytic leukemia-associated antigen (MLAA) gene. But the functional characterization of human KIAA0100 gene has remained unknown to date. Here, firstly, bioinformatic prediction of human KIAA0100 gene was carried out using online software;Secondly, human KIAA0100 gene expression was downregulated by the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) 9 system in U937 cells. Cell proliferation and apoptosis were next evaluated in KIAA0100-knockdown U937 cells. The bioinformatic prediction showed that human KIAA0100 gene was located on 17q11.2, and human KIAA0100 protein was located in the secretory pathway. Besides, human KIAA0100 protein contained a signal peptide, a transmembrane region, three types of secondary structures (alpha helix, extended strand, and random coil) , and four domains from mitochondrial protein 27 (FMP27). The observation on functional characterization of human KIAA0100 gene revealed that its downregulation inhibited cell proliferation, and promoted cell apoptosis in U937 cells. To summarize, these results suggest human KIAA0100 gene possibly comes within mitochondrial genome; moreover, it is a novel anti-apoptotic factor related to carcinogenesis or progression in acute monocytic leukemia, and may be a potential target for immunotherapy against acute monocytic leukemia.
ABSTRACT
Objective To construct the Hut78 cell line with EZH2 gene knocked into by CRISPR/Cas9 system. Methods The EZH2 expression vector pMD-18T-EZH2 with homologous arm and the sgRNA expression vector pSpCas9 (BB)-2A-Puro-sgRNA, which could cut the double stranded genomic DNA, were constructed, and the two vectors were co-transfected into Hut78 cells. Then the expression of EZH2 mRNA was detected by qPCR, and the expressions of EZH2 and H3K27me3 proteins were detected by Western blot assay. Results The pMD-18T-EZH2 and pSpCas9(BB)-2A-Puro-sgRNA recombinant vectors were confirmed by DNA sequencing. When Hut78 cells were transfected with the two recombinant plasmid, qPCR results showed that the expression of EZH2 mRNA was significantly increased, and Western blot analysis showed that the expressions of EZH2 and H3K27me3 proteins were significantly increased. Conclusion EZH2 gene is successfully knocked into Hut78 cells by CRISPR/Cas9 system.
ABSTRACT
Animal models are highly valuable systems that have been extensively used to elucidate human disease pathogenesis and to find therapeutic ways to treat human diseases .Since non-human primates are close to humans,monkeys are important model species in exploring the mechanisms and treatment of human neurodegenerative diseases , neuropsychiatric disorders, cognitive function, and neural circuits.However, due to the lack of embryonic stem cell lines in large animals, the traditional gene targeting technology is difficult to establish primate animal models of human diseases . CRISPR/Cas9, as a recently developed tool for genome modifications , has been successfully used to target genomic loci in mouse, rat, monkey, and other species.Here, we discuss the utilization of CRISPR /Cas9 technology in establishing monkey models for studying human neurodegenerative diseases .