ZFNs	Zinc-finger nucleases are fusions of the nonspecific DNA-cleavage domain with zinc finger DNA binding domain. The DNA binding domain can be engineered to direct the ZFN to specific desired DNA sequences, and ZFN induce targeted DSBs.
TALENs	Transcription activator-like effector nucleases are made by fusing a DNA cleavage domain to a TAL effector DNA binding domain. TAL effectors containing 33~35 amino acid repeat domains can be engineered to recognize base pair. Then TALENs induce targeted DNA DSBs.
CRISPR/Cas9	Clustered regularly interspaced short palindromic repeat- associated nuclease Cas9 is a prokaryotic immune system against foreign DNA in bacteria or archaea. They consist of a guide RNA (tracrRNA-crRNA)-being used for guiding the Cas9 nuclease to the desired DNA sequence, and Cas9 protein.
DSB	Double-strand break. A form of DNA damage caused by ZFN, TALEN and CRISPR/Cas9. Both DNA strands will be cleaved.
NHEJ	Non-homologous end joining. A DSB repair pathway which can relink broken ends together. It often leads to small insertions and deletions at the broken site.
HDR	Homology-directed repair. Another DSB repair pathway by which the donor molecule will be inserted at targeted sites. By HDR, single, multiple transgenes, or single nucleotide substitutions can all be inserted.
Indel—insertion/deletion	A molecular biology term. Insert or delete bases in DNA.
sgRNA—single-guide RNA	Consists of crRNA and tracrRNA, can direct Cas9-mediated genome editing.
PAM	Proto-spacer adjacent motifs on crRNA are particularly required and recognized by Cas9 protein.
crRNA	One CRISPR RNA base pair of the guide RNA in CRISPR/Cas9.
tracrRNA	Trans-activating chimeric RNA. Another CRISPR RNA base pair in CRISSPR/Cas9. It can promote crRNA processing.
Lentiviral Vectors (LVs)—Lentiviruses	The replication-defective retroviruses that are applied to introduce the target gene in vivo or in vitro for genome editing.
Adenoviral Vectors (AdVs)—Adenoviruses	The replication-defective viruses belong to the family of Adenoviridae. They are always used to carry the designed gene into targeted tissues or cells in vivo or in vitro for genome editing.
Adeno-associated viral Vectors (AAVs)—Adeno-associated viruses	The commonly used delivery vector in genome editing technologies for its potential site-specific integration ability and low immunogenic characteristics. They are icosahedral non-enveloped viruses in Dependovirus genus of Parvoviridae family.
Liposomes	Lipid made vesicles which can encapsulate designed DNA or RNA, and carry them into target tissues and cells by fusing to the cell membrane for genome editing in vivo or in vitro.
Polymer	Co-polymers made vesicles which can encapsulate both genes and proteins, and form particles with different sizes. They can also be utilized for designed genes or proteins delivery in vivo or in vitro to achieve gene editing therapy.
Cell-penetrating peptides (CPP)	Small peptides which can combine with target genes or proteins, and translocate across cell membranes to achieve the delivery and genome editing in vivo or in vitro.