TALEN: A Tool for Genome Editing

Genome editing by engineered nuclease enzymes, which, induce DNA double strand break (DSB) followed by the activation of repair mechanisms, is of great importance to researchers in the field of biology and medicine. TALEN (Activator Transistor like Effector Nuclease) as a tool for genome editing is widely used in a variety of organisms and cells to study the role of genes or mutations in biological or pathological pathways, create model organisms or a therapeutic approach to single genetic disorders such as sickle cell anemia. TALE consists of: 1) N-terminal T3S signal, 2) Central tandem repeat domain, 3) C-terminal nuclear localization signal (NLS) and 4) Acidic transcriptional activation domain (AD, fused to a non-specific domain for DNA double strand break). DSB can undergo changes such as insertion, deletion, inversion, translocation through two major repair pathways of NHEJ and HDR. In this review article, we will first discuss the TALEN technology, assembly of custom TALEN and its transmission techniques. This is followed by studies on genome editing, various repair mechanisms and donor design in the HDR pathway. Finally, the applications of this technology will be discussed.