Poly(A)-specific ribonuclease (PARN), also known as polyadenylate-specific ribonuclease or deadenylating nuclease (DAN), is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that in humans is encoded by the ''PARN''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Function
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.
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.
References
Further reading
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EC 3.1.13
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