Cas12a (CRISPR-associated protein 12a, previously known as Cpf1) is an RNA-guided endonuclease that forms an essential component of the CRISPR systems found in some bacteria and archaea.

[1] As with Cas9 and other Cas proteins, the programmable DNA-targeting activity of Cas12a makes it a useful tool for biotechnology and biological research applications.

[4] The acronym CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) refers to the invariant DNA sequences found in bacteria and archaea which encode Cas proteins and their crRNAs.

It was renamed in 2015 after a broader rationalization of the names of Cas (CRISPR associated) proteins to correspond to their sequence homology.

[6] This reduced size renders Cas12a more suitable for applications such as in vivo delivery via adeno-associated virus (AAV), which have limited DNA packaging capacity due to their small capsids.

[5] The CRISPR-Cas12a system consist of a Cas12a enzyme and a guide RNA that finds and positions the complex at the correct spot on the double helix to cleave target DNA.

The proteins also cut DNA at different places, offering researchers more options when selecting an editing site.

[11] Multiple aspects influence target efficiency and specificity when using CRISPR, including guide RNA design.