CRISPR Core: Sigma-PSC Core

CRISPR/Cas systems have evolved within bacterial and archaeal organisms as a defense against invading viruses and plasmids. Recently, the type II CRISPR/Cas system from the bacterium Streptococcus pyogenes has been engineered to function in eukaryotic cells using two molecular components: a single Cas9 protein and a non-coding guide RNA (gRNA).1-7 The Cas9 endonuclease can be programmed with a single gRNA, directing a

DNA double-strand break (DSB) at a desired genomic location (Figure 1). Similar to DSBs induced by zinc finger nucleases (ZFNs), the cell then activates endogenous DNA repair processes, either non-homologous end joining (NHEJ) or homology-directed repair (HDR), to heal the targeted DSB.


The major Sigma CRISPR product classes covered include:

  1. Single vector CRISPR reagents (U6-gRNA/Cas9-GFP or U6-gRNA/Cas9-RFP).
  2. Dual vector CRISPR reagents (U6-gRNA plasmid + separate Cas9 plasmid)
  3. CRISPR Cas9-D10A nickases (i.e. RuvC minus) and paired gRNAs for reduced off-target
  4. RNA-only formats for embryo microinjection (includes Cas9 nucleases and paired nickases).
  5. Lentiviral particles (U6-gRNA/Puro-Cas9-GFP).