title: Polyamine oxidase 7 is a terminal catabolism-type enzyme in Oryza sativa and is specifically expressed in anthers.
abstract: Polyamine oxidase (PAO), which requires FAD as a cofactor, functions in polyamine catabolism. Plant PAOs are classified into two groups based on their reaction modes. The terminal catabolism (TC) reaction always produces 1,3-diaminopropane (DAP), H2O2, and the respective aldehydes, while the back-conversion (BC) reaction produces spermidine (Spd) from tetraamines, spermine (Spm) and thermospermine (T-Spm) and/or putrescine from Spd, along with 3-aminopropanal and H2O2. The Oryza sativa genome contains seven PAO-encoded genes termed OsPAO1-OsPAO7. To date, we have characterized four OsPAO genes. The products of these genes, i.e. OsPAO1, OsPAO3, OsPAO4 and OsPAO5, catalyze BC-type reactions. Whereas OsPAO1 remains in the cytoplasm, the other three PAOs localize to peroxisomes. Here, we examined OsPAO7 and its gene product. OsPAO7 shows high identity to maize ZmPAO1, the best characterized plant PAO having TC-type activity. OsPAO7 seems to remain in a peripheral layer of the plant cell with the aid of its predicted signal peptide and transmembrane domain. Recombinant OsPAO7 prefers Spm and Spd as substrates, and it produces DAP from both substrates in a time-dependent manner, indicating that OsPAO7 is the first TC-type enzyme identified in O. sativa. The results clearly show that two types of PAOs co-exist in O. sativa. Furthermore, OsPAO7 is specifically expressed in anthers, with an expressional peak at the bicellular pollen stage. The physiological function of OsPAO7 in anthers is discussed.
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi, 980-8577 Japan.
authors.forename: Taibo
authors.initials: T
authors.lastname: Liu
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi, 980-8577 Japan.
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama, 370-0290 Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Niitsu
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi, 980-8577 Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Maeda
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi, 980-8577 Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi, 980-8577 JapanShokei Gakuin University, 4-10-1 Yurigaoka, Natori, Miyagi, 981-1295 Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kamio
authors.affiliation: Biodiversity and Climate Research Center, Laboratory Centre, Georg-Voigt-Str. 14-16, D-60325 Frankfurt am Main, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Berberich
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi, 980-8577 Japan kusano@ige.tohoku.ac.jp.
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Kusano
mesh_terms: D000447:Aldehydes / Q000378:metabolism; D003959:Diamines / Q000378:metabolism; D035264:Flowers / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D017930:Genes, Reporter; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D009928:Organ Specificity; D012275:Oryza / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics / Q000378:metabolism*; D020675:Peroxisomes / Q000378:metabolism; D010802:Phylogeny; D019441:Plant Epidermis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011073:Polyamines / Q000378:metabolism*; D021382:Protein Sorting Signals; D011700:Putrescine / Q000378:metabolism; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000031:analogs & derivatives / Q000378:metabolism; D000097667:Polyamine Oxidase
chemical_list: D000447:Aldehydes; D003959:Diamines; D006861:Hydrogen Peroxide; D000587:Oxidoreductases Acting on CH-NH Group Donors; D010940:Plant Proteins; D011073:Polyamines; D021382:Protein Sorting Signals; D011700:Putrescine; D013095:Spermidine; D013096:Spermine; D000097667:Polyamine Oxidase; C021097:thermospermine; C009475:trimethylenediamine
keywords: Anther; Oryza sativa; Polyamine; Polyamine oxidase; Terminal catabolism