genome-editing-in-mammalian-cell-lines-using-crispr-cas

Genome Editing in Mammalian Cell Lines using CRISPR-Cas

The clustered regularly interspaced short palindromic repeats (CRISPR) system functions naturally in bacterial adaptive immunity, but has been ...

Agency for Science Technology and Research

Nanyang Technological University

Genome editing using programmable DNA endonucleases enables the engineering of eukaryotic cells and living organisms with desirable properties or traits. Among the various molecular scissors that have been developed to date, the most versatile and easy-to-use family of nucleases derives from CRISPR-Cas, which exists naturally as an adaptive immune system in bacteria. Recent advances in the CRISPR-Cas technology have expanded our ability to manipulate complex genomes for myriad biomedical and biotechnological applications. Some of these applications are time-sensitive or demand high spatial precision. Here, we describe the use of an inducible CRISPR-Cas9 system, termed iCas, which we have developed to enable rapid and tight control of genome editing in mammalian cells. The iCas system can be switched on or off as desired through the introduction or removal of the small molecule tamoxifen or its related analogs such as 4-hydroxytamoxifen (4-HT).

Rapid Control of Genome Editing in Human Cells by Chemical-Inducible CRISPR-Cas Systems.

While CRISPR-Cas systems hold tremendous potential for engineering the human genome, it is unclear how well each system performs against one another in both non-homologous end joining (NHEJ)-mediated and homology-directed repair (HDR)-mediated genome editing.

Systematic evaluation of CRISPR-Cas systems reveals design principles for genome editing in human cells.

The availability of different host chassis will greatly expand the range of applications in synthetic biology. Members of the Acetobacteraceae family of Gram-negative bacteria form an attractive class of nonmodel microorganisms that can be exploited to produce industrial chemicals, food and beverage, and biomaterials. One such biomaterial is bacterial cellulose, which is a strong and ultrapure natural polymer used in tissue engineering scaffolds, wound dressings, electronics, food additives, and other products. However, despite the potential of Acetobacteraceae in biotechnology, there has been considerably little effort to fundamentally reprogram the bacteria for enhanced performance. One limiting factor is the lack of a well-characterized, comprehensive toolkit to control expression of genes in biosynthetic pathways and regulatory networks to optimize production and cell viability. Here, we address this shortcoming by building an expanded genetic toolkit for synthetic biology applications in Acetobacteraceae. We characterized the performance of multiple natural and synthetic promoters, ribosome binding sites, terminators, and degradation tags in three different strains, namely, Gluconacetobacter xylinus ATCC 700178, Gluconacetobacter hansenii ATCC 53582, and Komagataeibacter rhaeticus iGEM. Our quantitative data revealed strain-specific and common design rules for the precise control of gene expression in these industrially relevant bacterial species. We further applied our tools to synthesize a biodegradable cellulose-chitin copolymer, adjust the structure of the cellulose film produced, and implement CRISPR interference for ready down-regulation of gene expression. Collectively, our genetic parts will enable the efficient engineering of Acetobacteraceae bacteria for the biomanufacturing of cellulose-based materials and other commercially valuable products.

Article	Year
Rapid Control of Genome Editing in Human Cells by Chemical-Inducible CRISPR-Cas Systems. Methods in molecular biology (Clifton, N.J.)\| PubMed ID: 29754234	2018
Systematic evaluation of CRISPR-Cas systems reveals design principles for genome editing in human cells. Genome biology\| PubMed ID: 29843790	2018
An Expanded Synthetic Biology Toolkit for Gene Expression Control in Acetobacteraceae. ACS synthetic biology\| PubMed ID: 30865830	2019

Meng How Tan

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