RNA exonuclease that binds to the 3'-end of histone mRNAs and degrades them, suggesting that it plays an essential role in histone mRNA decay after replication ( ). A 2' and 3'-hydroxyl groups at the last nucleotide of the histone 3'-end is required for efficient degradation of RNA substrates ( ). Also able to degrade the 3'-overhangs of short interfering RNAs (siRNAs) in vitro, suggesting a possible role as regulator of RNA interference (RNAi) . Required for binding the 5'-ACCCA-3' sequence present in stem-loop structure (, ). Able to bind other mRNAs (, ). Required for 5.8S rRNA 3'-end processing (By similarity). Also binds to 5.8s ribosomal RNA (By similarity). Binds with high affinity to the stem-loop structure of replication-dependent histone pre-mRNAs ( ). In vitro, does not have sequence specificity . In vitro, has weak DNA exonuclease activity . In vitro, shows biphasic kinetics such that there is rapid hydrolysis of the last three unpaired RNA nucleotides in the 39 flanking sequence followed by a much slower cleavage through the stem that occurs over a longer incubation period in the order of hours .
Subcellular locations: Cytoplasm, Nucleus, Nucleus, Nucleolus