RNA-directed Cleavage and Modification of DNA using CasY (CRISPR-CasY)

Patent Status

Additional Patent Pending

Brief Description

The CRISPR-Cas system is now understood to confer bacteria and archaea with acquired immunity against phage and viruses. CRISPR-Cas systems consist of Cas proteins, which are involved in acquisition, targeting and cleavage of foreign DNA or RNA, and a CRISPR array, which includes direct repeats flanking short spacer sequences that guide Cas proteins to their targets.  Class 2 CRISPR-Cas are streamlined versions in which a single Cas protein bound to RNA is responsible for binding to and cleavage of a targeted sequence. The programmable nature of these minimal systems has facilitated their use as a versatile technology that is revolutionizing the field of genome manipulation.  Current CRISPR Cas technologies are based on systems from cultured bacteria, leaving untapped the vast majority of organisms that have not been isolated.  There is a need in the art for additional Class 2 CRISPR/Cas systems (e.g., Cas protein plus guide RNA combinations).

UC Berkeley researchers discovered a new type of Cas protein, CasY.  CasY is short compared to previously identified CRISPR-Cas endonucleases, and thus use of this protein as an alternative provides the advantage that the nucleotide sequence encoding the protein is relatively short.  CasY utilizes a guide RNA to perform double stranded cleavage of DNA. The researchers introduced CRISPR-CasY into E. coli, finding that they could block genetic material introduced into the cell.  Further research results indicated that CRISPR-CasY operates in a manner analogous to CRISPR-Cas9, but utilizing an entirely distinct protein architecture containing different catalytic domains.   CasY is also expected to function under different conditions (e.g., temperature) given the environment of the organisms that CasY was expressed in.  Similar to CRISPR Cas9, CasY enzymes are expected to have a wide variety of applications in genome editing and nucleic acid manipulation. 

Suggested uses

• Diagnostics

Advantages

• Functions under different conditions than current CRISPR-Cas proteins (e.g., lower temperatures)
• Nucleotide sequence encoding the CasY protein is short

Publication

New CRISPR–Cas systems from uncultivated microbes