Structure and molecular characterization of barley nudix hydrolase genes.
Putative nudix hydrolase (NUDX) genes, which encode amino acid sequences showing homology with those of Arabidopsis NUDXs and conserve nudix motif, were identified from barley. The 14 deduced barley NUDXs (HvNUDX1-14) were classified into established subfamilies, except for 8-oxo-deoxyguanosine 5'-triphosphate (8-oxo-dGTP) pyrophosphohydrolase and mRNA decapping enzyme subfamilies, and three substrate-unknown subfamilies. Drought and UV-C stresses, respectively, up-regulated 7 and 4 HvNUDX genes, but some homologs of Arabidopsis NUDXs showed different responses to abiotic stress. HvNUDX12 gene, belonging to diadenosine tetraphosphates (Ap₄A) pyrophosphohydrolase subfamily gene and up-regulated by UV-C, was expressed in Escherichia coli cells. The recombinant protein showed 8-oxo-dGTP, Ap₄A, and guanosine-3',5'-tetraphosphate (ppGpp) pyrophosphohydrolase activities, and the suppression of the lacZ amber mutation in a mutT-deficient E. coli cells caused by the incorporation of 8-oxo-GTP into mRNA was prevented to a significant degree. These results suggest that barley NUDXs have unique constitution and response of NUDX to abiotic stress.
a Institute of Plant Science and Resources , Okayama University , Okayama , Japan.
Sayuri
S
Tanaka
Makoto
M
Kihara
Manabu
M
Sugimoto
D000595:Amino Acid Sequence; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D001467:Hordeum / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D011755:Pyrophosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological; D000096964:Nudix Hydrolases
D011755:Pyrophosphatases; D000096964:Nudix Hydrolases
8-oxo-dGTP; UV-C; abiotic stress; barley; nudix hydrolase