Digests double-stranded RNA. Involved in the processing of primary rRNA transcript to yield the immediate precursors to the large and small rRNAs (23S and 16S). Also processes some mRNAs, and tRNAs when they are encoded in the rRNA operon (By similarity). Complements pre-crRNA and tracrRNA coprocessing defects in an rnc deletion in S.pyogenes strain 370, although this S.aureus strain does not have the corresponding CRISPR locus (PubMed:24270795). Endonucleolytic cleavage to 5'-phosphomonoester. Homodimer. Belongs to the ribonuclease III family.