Cas12a
Pronunciation: kaz-TWELVE-ay
A class 2 CRISPR-associated endonuclease that recognises a T-rich PAM and produces staggered (cohesive) double-strand breaks; also known as Cpf1. Written as 'Cas12a', not 'CAS12A'.
Full Definition
Cas12a (formerly Cpf1) is a type V CRISPR-Cas nuclease that differs from Cas9 in several key ways: it requires only a crRNA (not a tracrRNA), recognises a 5′ T-rich PAM (e.g., TTTV for AsCas12a), and generates staggered cuts with 5′ overhangs rather than the blunt ends produced by Cas9. Editors should use the current nomenclature 'Cas12a', noting that 'Cpf1' remains in older literature. Mixed-case rules apply: 'Cas12a', not 'CAS12A' or 'cas12a'. The organism prefix convention applies (AsCas12a for Acidaminococcus sp., LbCas12a for Lachnospiraceae bacterium).
Usage
Usage note: Use current name 'Cas12a' rather than the obsolete 'Cpf1', unless quoting historical literature. Flag 'Cpf1' in manuscripts and query the author about preferred nomenclature.
In Context
- "Cas12a was selected for its T-rich PAM compatibility with the GC-poor target region." — Methods section
- "The paper alternated between 'Cpf1' and 'Cas12a'; the author was queried to standardise nomenclature." — Editorial query