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Substrate specificity of the dsRNA unwinding/modifying activity.
Author(s) -
Nishikura K.,
Yoo C.,
Kim U.,
Murray J.M.,
Estes P.A.,
Cash F.E.,
Liebhaber S.A.
Publication year - 1991
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1991.tb04916.x
Subject(s) - rna silencing , biology , rna , biophysics , nucleotide , microbiology and biotechnology , biochemistry , rna interference , gene
Double‐stranded RNA (dsRNA) unwinding/modifying activity, which is present in a wide range of eukaryotic cells, has been previously shown to convert up to 50% of adenosine residues to inosines within intermolecular dsRNA. In the present study, we report that this activity also modifies, though slightly less efficiently, intramolecular double‐stranded regions of synthetic RNAs. Our results widen the range of the possible biological substrates for the activity since many stem and loop type RNA secondary structures (intramolecular dsRNA), present in eukaryotic as well as viral transcripts, can potentially serve as substrates. In addition, we have found that the dsRNA unwinding/modifying activity requires a double‐stranded region of at least 15–20 base pairs (bp) for substrate recognition. Furthermore, modification efficiency was found to be critically dependent on the length of the double‐stranded region; as the size decreased below 100 bp, it dropped precipitously. Our results suggest that efficient modification may occur only with relatively long (greater than 100 bp) dsRNA, perhaps because multiple copies of the enzyme must be bound.