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Genome Editing Tools
Published in Vineet Kumar, Vinod Kumar Garg, Sunil Kumar, Jayanta Kumar Biswas, Omics for Environmental Engineering and Microbiology Systems, 2023
Madhumita Barooah, Dibya Jyoti Hazarika
TALEN (transcription activator-like effector nuclease) is an excellent tool for the manipulation of genes through site-directed mutagenesis (Sun and Zhao, 2013). TALENs employ TAL proteins for DNA binding. These proteins are derived originally from a plant pathogenic bacterial genus Xanthomonas. The DNA-binding effectiveness of TAL proteins are so high that they can recognize even very short sequences for binding, i.e., 1–2 nucleotides. Furthermore, these nucleases consist of 34-amino-acid tandem repeats that ensure their binding to the target site (Juillerat et al., 2014; Jaiswal et al., 2019). Gene knock-in (HDR) and gene knockout (NHEJ) can be performed using TALENs. This system contains two protein domains, one of which recognizes and binds the very unique and specific target site and the second one is used for cleavage of a specific sequence at that unique site (Jaiswal et al., 2019). However, this technique is applied to manipulate the genomes of many eukaryotic targets such as mammalian cells, frog, zebrafish, mouse, rat, and chicken (Lei et al., 2012; Moore et al., 2012; Bloom et al., 2013; Qiu et al., 2013; Park et al., 2014; Chen et al., 2017).
Genomic Approaches for Understanding Abiotic Stress Tolerance in Plants
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Richa Rai, Amit Kumar Rai, Madhoolika Agrawal
TALENs are one of the substitutes to ZFNs and are identified as restriction enzymes that could be manipulated for cutting specific DNA sequences. Traditionally, TALENs are considered as long segments of transcription activator-like effector (TALE) sequences that occur naturally and join the Fokl domain with the carboxylic-terminal end of manipulated TALE repeat arrays (Christian et al., 2010). TALENs contain a customizable DNA-binding domain which is fused with non-specific Fokl nuclease domain (Christian et al., 2010). As compared to ZFNs, TALENs are involved in the interaction of individual nucleotide repeats of the target site and amino acid sequences of TAL effector proteins. They can generate overhangs by employing Fokl nuclease domain to persuade site-specific DNA cleavage. It has been widely used to generate non-homologous mutations with higher efficiencies in diverse organisms (Joung and Sander, 2012) TALE proteins consist of a central domain responsible for DNA binding, nuclear localization signal, and a domain that activates transcription of the target gene. DNA-binding domain in TALE monomers consists of a central repeat domain (CRD) that confers DNA binding and host specificity. The CRD consists of tandem repeats of 34 amino acid residues and each 34-amino acid long repeat in CRD binds to one nucleotide in the target nucleotide sequence.
Gene Therapy and Gene Correction
Published in Yashwant V. Pathak, Gene Delivery Systems, 2022
Manish P. Patel, Sagar A. Popat, Jayvadan K. Patel
Transcription activator–like effectors (TALEs) are a group of DNA binding proteins. They were discovered from the plant pathogen of Xanthomonas bacteria (Boch et al. 2010). Each TALE contains 33 to 35 amino acids, which are major building blocks. Amino acid at the twelfth and thirteenth residue are most valuable for DNA binding specificity, and they are called repeat-variable di-residues (RVDs) (Cermak et al. 2011).
Gene doping: Present and future
Published in European Journal of Sport Science, 2020
Rebeca Araujo Cantelmo, Alessandra Pereira da Silva, Celso Teixeira Mendes-Junior, Daniel Junqueira Dorta
Some techniques have been helpful to leverage research in the field of gene editing, increasingly contributing to gene editing development and improvement. Among these techniques, zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and particularly the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR associated protein 9 (CRISPR-Cas9) are noteworthy. These tools are applied in genetic manipulation and have diverse functions including gene introduction or replacement, precise DNA insertion or deletions of various lengths, and production of knock-in and knockout animals and plants. However, all these genome-editing techniques require several processes to evaluate and to regularize their practice so that the underlying risks are known and their misuse can be avoided in the future (Fears & Meulen, 2017; Mashimo, 2014).