Cas9 nuclease is an RNA-guided endonuclease that can catalyze cleavage of double stranded DNA. This kind of targeted nuclease is a powerful tool for genome editing with high precision. Cas9 protein forms a very stable ribonucleoprotein (RNP) complex with the guide RNA (gRNA) component of the CRISPR/Cas9 system. The Cas9 RNP complex can localize to the nucleus immediately upon entering the cell with the addition of a nuclear localization signal (NLS). There is no requirement for transcription and translation compared with mRNA or plasmid systems. Additionally, the Cas9 RNP complex is rapidly cleared from the cell minimizing the chance of off-target cleavage when compared to other systems (Kim, et al. 2014). This DNA-free system avoids the risk of inserting foreign DNA into the genome, which can be quite useful for gene editing-based disease therapy. GenScript has developed a Cas9-N-NLS nuclease which contains a nuclear localization sequence (NLS) on the N-terminus of the protein to meet all the researchers’ requirements (e.g. in vitro cleavage assay, RNP complex transfection, and micro injection).

Product Source:GenCrispr Cas9-N-NLS is produced by expression in an E. coli strain carrying a plasmid encoding the Cas9 gene from Streptococcus pyogenes with a N terminal nuclear localization signal (NLS).

Key Features
-DNA-free: no external DNA added to system
-High cleavage efficiency: NLS ensures the entry of Cas9 protein into nuclei
-Low off target: transient expression of Cas9 nuclease
-Time-saving: no need for transcription and translation

Applications
-Screening for highly efficient and specific targeting gRNAs by in vitro DNA cleavage.
-In vivo gene editing when combined with a specific gRNA by electroporation or injection.