Hypercompact CRISPR–Cas12j2 (CasΦ) enables genome editing, gene activation, and epigenome editing in plants

CRISPR-Cas9, -Cas12a, -Cas12b, and -Cas13 have been harnessed for genome engineering in human and plant cells (Liu et al., 2022). However, the large size of these Cas proteins (e.g. ∼190 kDa for SpCas9) makes them difficult to deliver into cells via a viral vector. The development of smaller Cas proteins will lead to reduced viral vector sizes that can be more widely adopted in versatile genome engineering systems. Recently, a CRISPR-Cas12j2 (CasΦ) system was discovered in huge phages and developed into a hypercompact genome editor due to the small size of Cas12j2 (∼80 kDa) (Pausch et al., 2020).