The function of PNLDC1 (PARN like ribonuclease domain containing exonuclease 1, Ensembl gene identifier ENSG00000146453) is as follows. 3'-exoribonuclease that has a preference for poly(A) tails of mRNAs, thereby efficiently degrading poly(A) tails (PubMed:27515512). Exonucleolytic degradation of the poly(A) tail is often the first step in the decay of eukaryotic mRNAs and is also used to silence certain maternal mRNAs translationally during oocyte maturation and early embryonic development (PubMed:27515512). May act as a regulator of multipotency in embryonic stem cells (By similarity). Is a critical factor for proper spermatogenesis, involved in pre-piRNAs processing to generate mature piRNAs (PubMed:34347949). {ECO:0000250|UniProtKB:B2RXZ1, ECO:0000269|PubMed:27515512, ECO:0000269|PubMed:34347949}.