saCas9 Null Mutant NLS Protein

The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 system is the latest RNA-guided, endonuclease tool in genome editing which allows for very specific genomic disruption and replacement.

The saCas9 Null Mutant Protein is created by mutating both cleavage domains of the wild type saCas9. Such a saCas9 protein retains its ability to bind to genomic DNA through gRNA:genomic DNA base pairing, however, the saCas9 Null Mutant does not introduce any genome modifications. Therefore, this protein can provide a useful negative control for CRISPR experiments. In addition, binding of the Null Mutant can act as a roadblock to hinder transcription, thus offering a useful tool to achieve reversible knock-down of gene expression.

The Cas9 nuclease from the bacteria Staphylococcus aureus, abbreviated saCas9, is gaining popularity as an alternative to spCas9 due to its relatively smaller size. The saCas9 PAM sequence is 5’-NNGRRN (preferably 5’-NNGRRT). saCas9 NLS Null Mutant contains a SV40 T antigen nuclear localization sequence (NLS) on the C-terminus of the protein.