InterPro domain: IPR036389

This domain superfamily is found in eukaryotic, bacterial and archeal ribonuclease III (RNAse III) proteins. RNAse III is a double stranded RNA-specific endonuclease [ 1 , 2 ]. Prokaryotic RNAse III is important in post-transcriptional control of mRNA stability and translational efficiency. It is involved in the processing of ribosomal RNA precursors. Prokaryotic RNAse III also plays a role in the maturation of tRNA precursors and in the processing of phage and plasmid transcripts. Eukaryotic RNase III's participate (through direct cleavage) in rRNA processing, in processing of small nucleolar RNAs (snoRNAs) and snRNA's (components of the spliceosome). In eukaryotes RNase III or RNaseIII like enzymes such as Dicer are involved in RNAi (RNA interference) and miRNA (micro-RNA) gene silencing [ 3 , 4 , 5 ].

Bacterial RNase III proteins are the simplest members of the RNase III family, comprising an N-terminal nuclease domain fused to a C-terminal dsRNA bindingdomain (dsRBD) [ 6 ]. The endonuclease domain structure has five helices where one of the helices is surrounded by the others.

1. Crystallographic and modeling studies of RNase III suggest a mechanism for double-stranded RNA cleavage. Structure 9, 1225-36
2. Noncatalytic assembly of ribonuclease III with double-stranded RNA. Structure 12, 457-66
3. RNase III enzymes and the initiation of gene silencing. Nat. Struct. Mol. Biol. 11, 214-8
4. Dicers at RISC; the mechanism of RNAi. Cell 117, 1-3
5. Ribonuclease III: new sense from nuisance. Int. J. Biochem. Cell Biol. 34, 116-29
6. Structure of the nuclease domain of ribonuclease III from M. tuberculosis at 2.1 A. Protein Sci. 14, 2744-50