The mut-7 subfamily is composed of Caenorhabditis elegans mut-7 and similar proteins found in plants and metazoans Mut-7 is implicated in posttranscriptional gene silencing It contains a DEDDy-type DnaQ-like 3'-5' exonuclease domain possessing three conserved sequence motifs  termed ExoI  ExoII and ExoIII  with a specific YX(3)D pattern at ExoIII