An RNase that has endonuclease and possibly 5'-3' exonuclease activity. Probably involved in maturation of rRNA and in some organisms also mRNA maturation and/or decay. Binds up to 2 Zn(2+) ions per subunit. It is not clear if Zn(2+) or Mg(2+) is physiologically important. Homodimer (Probable). May be a subunit of the RNA degradosome (By similarity). Belongs to the metallo-beta-lactamase superfamily. RNA-metabolizing metallo-beta-lactamase-like family. Bacterial RNase J subfamily.