Rice Nudix Hydrolase OsNUDX2 Sanitizes Oxidized Nucleotides

• Main Authors: Yuki Kondo (Author), Kazuhide Rikiishi (Author), Manabu Sugimoto (Author)
• Format: Book
• Published: MDPI AG, 2022-09-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/antiox11091805; 2076-3921
• Keywords: 8-oxo-dGTP; nudix hydrolase; <i>Oryza sativa</i>; transcriptional error; UV-C; Therapeutics. Pharmacology; RM1-950
• Source: Antioxidants, Vol 11, Iss 9, p 1805 (2022)

Nudix hydrolase (NUDX) hydrolyzes 8-oxo-(d)GTP to reduce the levels of oxidized nucleotides in the cells. 8-oxo-(d)GTP produced by reactive oxygen species (ROS) is incorporated into DNA/RNA and mispaired with adenine, causing replicational and transcriptional errors. Here, we identified a rice <i>OsNUDX2</i> gene, whose expression level was increased 15-fold under UV-C irradiation. The open reading frame of the <i>OsNUDX2</i> gene, which encodes 776 amino acid residues, was cloned into <i>Escherichia coli</i> cells to produce the protein of 100 kDa. The recombinant protein hydrolyzed 8-oxo-dGTP, in addition to dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP), as did Arabidopsis AtNUDX1; whereas the amino acid sequence of OsNUDX2 had 18% identity with AtNUDX1. OsNUDX2 had 14% identity with barley HvNUDX12, which hydrolyzes 8-oxo-dGTP and diadenosine tetraphosphates. Suppression of the <i>lacZ</i> amber mutation caused by the incorporation of 8-oxo-GTP into mRNA was prevented to a significant degree when the <i>OsNUDX2</i> gene was expressed in <i>mutT</i>-deficient <i>E. coli</i> cells. These results suggest that the different substrate specificity and identity among plant 8-oxo-dGTP-hydrolyzing NUDXs and OsNUDX2 reduces UV stress by sanitizing the oxidized nucleotides.