Dicer is an RNaseIII-like enzyme capable of cleaving double-stranded RNA (dsRNA) into smaller 21-23 nt RNA fragments known as short interfering RNA (siRNAs). It targets the selective degradation of complementary RNAs in a posttranscriptional gene silencing (PTGS) manner and is key for cell differentiation and development. Unlike long-dsRNA-dependent PTGS which is limited to certain cell types, siRNA can act in a wide variety of cells.
