3′-to-5’exoribonuclease that preferentially degrades DNA and RNA oligonucleotides composed of only two nucleotides (PubMed:23741365, PubMed:30926754, PubMed:31588022, PubMed:32365187). Binds and degrades longer oligonucleotides with a lower affinity (PubMed:30926754, PubMed:31588022, PubMed:32365187). Plays dual roles in mitochondria, scavenging nanoRNAs (small RNA oligonucleotides of <5 nucleotides) that are produced by the degradosome and clearing short RNAs that are generated by RNA processing (PubMed:30926754, PubMed:31588022, PubMed:32365187). Essential for correct initiation of mitochondrial transcription, degrading mitochondrial RNA dinucleotides to prevent RNA-primed transcription at non-canonical sites in the mitochondrial genome (PubMed:31588022). Essential for embryonic development (By similarity). ; [Isoform 3]: 3'-to-5'exoribonuclease that preferentially degrades DNA and RNA oligonucleotides composed of only two nucleotides.
