HIGLE is a bifunctional homing endonuclease that directly interacts with HYL 1 and SERRATE in Arabidopsis thaliana

A highly coordinated complex known as the microprocessor precisely processes primary transcripts of MIRNA genes into mature mi RNA s. In plants, the microprocessor minimally consists of three components: Dicer‐like protein 1 ( DCL 1), HYPONASTIC LEAF 1 ( HYL 1), and SERRATE ( SE ). To precisely modulate mi RNA maturation, the microprocessor cooperates with at least 12 proteins in plants. In addition, we here show the involvement of a novel gene, HYL 1‐interacting GIY ‐ YIG ‐like endonuclease ( HIGLE ). The encoded protein has a GIY ‐ YIG domain that is generally found within a class of homing endonucleases. HIGLE directly interacts with the microprocessor components HYL 1 and SE . Unlike the functions of other GIY ‐ YIG endonucleases, the catalytic core of HIGLE has both DN ase and RN ase activities that sufficiently processes mi RNA precursors into short fragments in vitro .