title: Analysis of Arabidopsis growth factor gene 1 (GFG1) encoding a nudix hydrolase during oxidative signaling.
abstract: Maintenance of pyridine nucleotide homeostasis is vital for normal growth and development of plants and animals. We demonstrate that Arabidopsis Growth Factor Gene 1 (GFG1; At4g12720) encoding a nudix hydrolase, is an NADH pyrophosphatase and ADP-ribose pyrophosphatase. The affinity for NADH and ADP-ribose indicates that this enzyme could serve as a connection between sensing cellular redox changes and downstream signaling. GFG1 transcript levels were rapidly and transiently induced during both biotic stresses imposed by avirulent pathogens and abiotic stresses like ozone and osmoticum. T-DNA knock out plants of GFG1 gene, gfg1-1, exhibit pleiotropic phenotypes such as reduced size, increased levels of reactive oxygen species and NADH, microscopic cell death, constitutive expression of pathogenesis-related genes and enhanced resistance to bacterial pathogens. The recombinant protein failed to complement the mutator deficiency in SBMutT- strain of Escherichia coli, suggesting this protein may not play a role in sanitizing the nucleotide pool. Based on rapid transcriptional changes in response to various stresses, substrate specificity of the enzyme, and analysis of the knock out mutant, we propose that GFG1 is a key gene linking cellular metabolism and oxidative signaling.
authors.affiliation: Department of Biochemistry and Molecular Biology, 246 Noble Research center, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Niranjani
authors.initials: N
authors.lastname: Jambunathan
authors.forename: Ramamurthy
authors.initials: R
authors.lastname: Mahalingam
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D017209:Apoptosis; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010126:Ozone / Q000494:pharmacology; D044224:Pseudomonas syringae / Q000502:physiology; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D013481:Superoxides / Q000494:pharmacology; D000096964:Nudix Hydrolases
chemical_list: D000246:Adenosine Diphosphate Ribose; D029681:Arabidopsis Proteins; D029968:Escherichia coli Proteins; D006861:Hydrogen Peroxide; D009243:NAD; D010126:Ozone; D011755:Pyrophosphatases; D017382:Reactive Oxygen Species; D013481:Superoxides; D000096964:Nudix Hydrolases; C052211:mutT protein, E coli