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 NLS-Cas9-NLS nuclease which contains a nuclear localization sequence (NLS) on both ends of the protein to meet all the researchers’ requirements (e.g. in vitro cleavage assay, RNP complex transfection, and micro injection).

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

Key Features
-DNA-free: no external DNA added to system
-High cleavage efficiency: Double NLS ensures the efficient 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.