Open AccessArabidopsis thaliana endonuclease V is a ribonuclease specific for inosine-containing single-stranded RNA
Author(s) -
Mitsuaki Endo,
Jung In Kim,
Narumi Shioi,
Shigenori Iwai,
Isao Kuraoka
Publication year - 2021
Publication title -
open biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.078
H-Index - 53
ISSN - 2046-2441
DOI - 10.1098/rsob.210148
Subject(s) - rna editing , rna , biology , adar , inosine , biochemistry , microbiology and biotechnology , dna , rna silencing , oligonucleotide , phosphodiester bond , nucleic acid analogue , rnase h , rnase p , adenosine , nucleic acid thermodynamics , gene , rna interference
Endonuclease V is highly conserved, both structurally and functionally, from bacteria to humans, and it cleaves the deoxyinosine-containing double-stranded DNA inEscherichia coli , whereas inHomo sapiens it catalyses the inosine-containing single-stranded RNA. Thus, deoxyinosine and inosine are unexpectedly produced by the deamination reactions of adenine in DNA and RNA, respectively. Moreover, adenosine-to-inosine (A-to-I) RNA editing is carried out by adenosine deaminase acting on dsRNA (ADARs). We focused onArabidopsis thaliana endonuclease V (AtEndoV) activity exhibiting variations in DNA or RNA substrate specificities. Since no ADAR was observed for A-to-I editing inA. thaliana , the possibility of inosine generation by A-to-I editing can be ruled out. Purified AtEndoV protein cleaved the second and third phosphodiester bonds, 3′ to inosine in single-strand RNA, at a low reaction temperature of 20–25°C, whereas the AtEndoV (Y100A) protein bearing a mutation in substrate recognition sites did not cleave these bonds. Furthermore, AtEndoV, similar to human EndoV, prefers RNA substrates over DNA substrates, and it could not cleave the inosine-containing double-stranded RNA. Thus, we propose the possibility that AtEndoV functions as an RNA substrate containing inosine induced by RNA damage, and not by A-to-I RNA editingin vivo .