Zinc phosphodiesterase, which displays some tRNA 3'-processing endonuclease activity of nuclear and mitochondrial pre-tRNA. Probably involved in tRNA maturation, by removing a 3'-trailer from precursor tRNA. May participate in tRNA processing in the developing embryo. Endonucleolytic cleavage of RNA, removing extra 3' nucleotides from tRNA precursor, generating 3' termini of tRNAs. A 3'-hydroxy group is left at the tRNA terminus and a 5'-phosphoryl group is left at the trailer molecule. Homodimer. Maternally expressed. Highly expressed in ovarian nurse cells and transferred into the nascent oocyte. By juvenile hormone (JH). The dual subcellular location may be due to some alternative splicing and/or initiation that changes the initiator methionine. Belongs to the RNase Z family.