[Genome Editing Tools and their Application in Experimental Ophthalmology].

New genome editing tools in molecular biology are revolutionising precise genome surgery and have greatly influenced experimental ophthalmology too. Aside from the commonly used nuclease-based platforms, such as the zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALEN), CRISPR/Cas systems, clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) genes, perform very efficiently in site-specific DNA cleavage within living cells. DNA double strand breaks (DSB) are repaired through two different conserved repair pathways: NHEJ (non-homologous end joining) and HDR (homology directed repair). By using the correct DNA templates, these repair pathways can be used to knock out defective genes or to repair mutations. Genome editing technology lays the ground for new strategies in basic science, biotechnology, and biomedical science, as well as clinical studies with genome editing. Therapeutic gene editing strategies are now concentrating on diseases in the retina, due to the comparatively easy accessibility of the eye and with local application in vivo.

Yanik M ，Wende W ，Stieger K 《-》

A history of genome editing in mammals.

Fernández A ，Josa S ，Montoliu L 《-》

Gene Editing With TALEN and CRISPR/Cas in Rice.

Engineered, site-specific nucleases induce genomic double-strand DNA breaks and break repair processes enable genome editing in a plethora of eukaryotic genomes. TALENs (transcription activator-like effector nucleases) and CRISPR/Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins) are potent biotechnological tools used for genome editing. In rice, species-tailored editing tools have proven to be efficient and easy to use. Both tools are capable of generating DNA double-strand breaks (DSBs) in vivo and such breaks can be repaired either by error-prone NHEJ (nonhomologous end joining) that leads to nucleotide insertions or deletions or by HDR (homology-directed repair) if an appropriate exogenous DNA template is provided. NHEJ repair often results in gene knockout, while HDR results in precise nucleotide sequence or gene replacement. In this review, we revisit the molecular mechanisms underlying DSB repair in eukaryotes and review the TALEN and CRISPR technologies (CRISPR/Cas9, CRISPR/Cpf1, and Base Editor) developed and utilized for genome editing by scientists in rice community.

Bi H ，Yang B 《-》

[The research advances and applications of genome editing in hereditary eye diseases].

Cai SW ，Zhang Y ，Hou MZ ，Liu Y ，Li XR ... -  《-》

Designed nucleases for targeted genome editing.

Targeted genome-editing technology using designed nucleases has been evolving rapidly, and its applications are widely expanding in research, medicine and biotechnology. Using this genome-modifying technology, researchers can precisely and efficiently insert, remove or change specific sequences in various cultured cells, micro-organisms, animals and plants. This genome editing is based on the generation of double-strand breaks (DSBs), repair of which modifies the genome through nonhomologous end-joining (NHEJ) or homology-directed repair (HDR). In addition, designed nickase-induced generation of single-strand breaks can also lead to precise genome editing through HDR, albeit at relatively lower efficiencies than that induced by nucleases. Three kinds of designed nucleases have been used for targeted DSB formation: zinc-finger nucleases, transcription activator-like effector nucleases, and RNA-guided engineered nucleases derived from the bacterial clustered regularly interspaced short palindromic repeat (CRISPR)-Cas (CRISPR-associated) system. A growing number of researchers are using genome-editing technologies, which have become more accessible and affordable since the discovery and adaptation of CRISPR-Cas9. Here, the repair mechanism and outcomes of DSBs are reviewed and the three types of designed nucleases are discussed with the hope that such understanding will facilitate applications to genome editing.

Lee J ，Chung JH ，Kim HM ，Kim DW ，Kim H ... -  《-》