Poly(A)-specific ribonuclease (PARN), also known as polyadenylate-specific ribonuclease or deadenylating nuclease (DAN), is an enzyme that in humans is encoded by the PARN gene. [5] [6]
Exonucleolytic degradation of the poly(A) tail is often the first step in the decay of eukaryotic mRNAs. The amino acid sequence of poly(A)-specific ribonuclease shows homology to the RNase D family of 3'-exonucleases. The protein appears to be localized in both the nucleus and the cytoplasm. It is not stably associated with polysomes or ribosomal subunits. [6] Hereditary mutations in PARN lead to the bone marrow failure disease dyskeratosis congenita which is caused by defective telomerase RNA processing and degradation in patients. [7] [8] [9] [10] [11] [12] [13]