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Pandey H, Yadav B, Shah K, Kaur R, Choudhary D, Sharma N, Rishi V. A new method for the robust expression and single-step purification of dCas9 for CRISPR interference/activation (CRISPRi/a) applications. Protein Expr Purif 2024; 220:106500. [PMID: 38718989 DOI: 10.1016/j.pep.2024.106500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/01/2024] [Accepted: 05/05/2024] [Indexed: 05/12/2024]
Abstract
CRISPR-Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated enzyme 9) is known for its simplicity, versatility, and scalability in genome editing applications. In vitro Cas9, when complexed with sgRNA, binds and cleaves the complementary target sequences with almost perfect precision. The enzyme is exploited for various applications in understanding and changing gene function. dCas9 (deactivated or dead Cas9) is a double mutated version of Cas9 that bears mutations in the nuclease domains of the enzyme and thus cannot cleave the target DNA. dCas9 is equally advantageous since it can alter gene expression using various transcriptional activators CRISPRa and repressors CRISPRi. Additionally, dCas9 can bind to the desired target gene without cleaving it, making it a unique reagent to study the kinetics and stability of RNA-protein-DNA interactions required to design more efficient and specific gene-editing nucleases. An appreciable quantity of pure and homogeneous protein is needed to characterise dCas9 for its structural and functional understanding. This study used an N-terminal acidic tag to express the dCas9 in an E. coli-bacterial host. A simple single-step protocol for robust and efficient production of dCas9 has been described. The study and methods are distinctive as the purification is performed in a single step using inexpensive multi-modal hydroxyapatite chromatography. The purified protein can be used in different in vitro and in vivo studies.
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Affiliation(s)
- Harshita Pandey
- National Agri-Food Biotechnology Institute, Knowledge City, Sector 81, Mohali, Punjab, 140306, India; Regional Center for Biotechnology, Faridabad, Haryana, 160014, India
| | - Binduma Yadav
- National Agri-Food Biotechnology Institute, Knowledge City, Sector 81, Mohali, Punjab, 140306, India; Regional Center for Biotechnology, Faridabad, Haryana, 160014, India
| | - Koushik Shah
- National Agri-Food Biotechnology Institute, Knowledge City, Sector 81, Mohali, Punjab, 140306, India
| | - Raminder Kaur
- National Agri-Food Biotechnology Institute, Knowledge City, Sector 81, Mohali, Punjab, 140306, India
| | - Diksha Choudhary
- National Agri-Food Biotechnology Institute, Knowledge City, Sector 81, Mohali, Punjab, 140306, India; Regional Center for Biotechnology, Faridabad, Haryana, 160014, India
| | - Nishtha Sharma
- National Agri-Food Biotechnology Institute, Knowledge City, Sector 81, Mohali, Punjab, 140306, India
| | - Vikas Rishi
- National Agri-Food Biotechnology Institute, Knowledge City, Sector 81, Mohali, Punjab, 140306, India.
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Jeong SH, Kim HJ, Lee SJ. New Target Gene Screening Using Shortened and Random sgRNA Libraries in Microbial CRISPR Interference. ACS Synth Biol 2023; 12:800-808. [PMID: 36787424 PMCID: PMC10028695 DOI: 10.1021/acssynbio.2c00595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
CRISPR interference (CRISPRi) screening has been used for identification of target genes related to specific phenotypes using single-molecular guide RNA (sgRNA) libraries. In CRISPRi screening, the sizes of random sgRNA libraries contained with the original target recognition sequences are large (∼1012). Here, we demonstrated that the length of the target recognition sequence (TRS) can be shortened in sgRNAs from the original 20 nucleotides (N20) to 9 nucleotides (N9) that is still sufficient for dCas9 to repress target genes in the xylose operon of Escherichia coli, regardless of binding to a promoter or open reading frame region. Based on the results, we constructed random sgRNA plasmid libraries with 5'-shortened TRS lengths, and identified xylose metabolic target genes by Sanger sequencing of sgRNA plasmids purified from Xyl- phenotypic cells. Next, the random sgRNA libraries were harnessed to screen for target genes to enhance violacein pigment production in synthetic E. coli cells. Seventeen target genes were selected by analyzing the redundancy of the TRS in sgRNA plasmids in dark purple colonies. Among them, seven genes (tyrR, pykF, cra, ptsG, pykA, sdaA, and tnaA) have been known to increase the intracellular l-tryptophan pool, the precursor of a violacein. Seventeen cells with a single deletion of each target gene exhibited a significant increase in violacein production. These results indicate that using shortened random TRS libraries for CRISPRi can be simple and cost-effective for phenotype-based target gene screening.
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Affiliation(s)
- Song Hee Jeong
- Department of Systems Biotechnology, and Institute of Microbiomics, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Hyun Ju Kim
- Department of Systems Biotechnology, and Institute of Microbiomics, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Sang Jun Lee
- Department of Systems Biotechnology, and Institute of Microbiomics, Chung-Ang University, Anseong 17546, Republic of Korea
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Jeong SH, Lee HJ, Lee SJ. Recent Advances in CRISPR-Cas Technologies for Synthetic Biology. J Microbiol 2023; 61:13-36. [PMID: 36723794 PMCID: PMC9890466 DOI: 10.1007/s12275-022-00005-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/15/2022] [Accepted: 11/15/2022] [Indexed: 02/02/2023]
Abstract
With developments in synthetic biology, "engineering biology" has emerged through standardization and platformization based on hierarchical, orthogonal, and modularized biological systems. Genome engineering is necessary to manufacture and design synthetic cells with desired functions by using bioparts obtained from sequence databases. Among various tools, the CRISPR-Cas system is modularly composed of guide RNA and Cas nuclease; therefore, it is convenient for editing the genome freely. Recently, various strategies have been developed to accurately edit the genome at a single nucleotide level. Furthermore, CRISPR-Cas technology has been extended to molecular diagnostics for nucleic acids and detection of pathogens, including disease-causing viruses. Moreover, CRISPR technology, which can precisely control the expression of specific genes in cells, is evolving to find the target of metabolic biotechnology. In this review, we summarize the status of various CRISPR technologies that can be applied to synthetic biology and discuss the development of synthetic biology combined with CRISPR technology in microbiology.
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Affiliation(s)
- Song Hee Jeong
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Ho Joung Lee
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea
| | - Sang Jun Lee
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Republic of Korea.
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Lee HJ, Lee SJ. Advances in Accurate Microbial Genome-Editing CRISPR Technologies. J Microbiol Biotechnol 2021; 31:903-911. [PMID: 34261850 PMCID: PMC9723281 DOI: 10.4014/jmb.2106.06056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 12/15/2022]
Abstract
Previous studies have modified microbial genomes by introducing gene cassettes containing selectable markers and homologous DNA fragments. However, this requires several steps including homologous recombination and excision of unnecessary DNA regions, such as selectable markers from the modified genome. Further, genomic manipulation often leaves scars and traces that interfere with downstream iterative genome engineering. A decade ago, the CRISPR/Cas system (also known as the bacterial adaptive immune system) revolutionized genome editing technology. Among the various CRISPR nucleases of numerous bacteria and archaea, the Cas9 and Cas12a (Cpf1) systems have been largely adopted for genome editing in all living organisms due to their simplicity, as they consist of a single polypeptide nuclease with a target-recognizing RNA. However, accurate and fine-tuned genome editing remains challenging due to mismatch tolerance and protospacer adjacent motif (PAM)-dependent target recognition. Therefore, this review describes how to overcome the aforementioned hurdles, which especially affect genome editing in higher organisms. Additionally, the biological significance of CRISPR-mediated microbial genome editing is discussed, and future research and development directions are also proposed.
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Affiliation(s)
- Ho Joung Lee
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Sang Jun Lee
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea
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Lee HJ, Kim HJ, Lee SJ. Mismatch Intolerance of 5'-Truncated sgRNAs in CRISPR/Cas9 Enables Efficient Microbial Single-Base Genome Editing. Int J Mol Sci 2021; 22:6457. [PMID: 34208669 PMCID: PMC8235755 DOI: 10.3390/ijms22126457] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 12/11/2022] Open
Abstract
The CRISPR/Cas9 system has recently emerged as a useful gene-specific editing tool. However, this approach occasionally results in the digestion of both the DNA target and similar DNA sequences due to mismatch tolerance, which remains a significant drawback of current genome editing technologies. However, our study determined that even single-base mismatches between the target DNA and 5'-truncated sgRNAs inhibited target recognition. These results suggest that a 5'-truncated sgRNA/Cas9 complex could be used to negatively select single-base-edited targets in microbial genomes. Moreover, we demonstrated that the 5'-truncated sgRNA method can be used for simple and effective single-base editing, as it enables the modification of individual bases in the DNA target, near and far from the 5' end of truncated sgRNAs. Further, 5'-truncated sgRNAs also allowed for efficient single-base editing when using an engineered Cas9 nuclease with an expanded protospacer adjacent motif (PAM; 5'-NG), which may enable whole-genome single-base editing.
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Affiliation(s)
| | | | - Sang Jun Lee
- Department of Systems Biotechnology and Institute of Microbiomics, Chung-Ang University, Anseong 17546, Korea; (H.J.L.); (H.J.K.)
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