title: Cloning and characterization of Arabidopsis and Brassica juncea flavin-containing amine oxidases.
abstract: Polyamines (PAs) are low molecular weight metabolites involved in various physiological and developmental processes in eukaryotic and prokaryotic cells. The cellular PA level is regulated in part by the action of amine oxidases (AOs) including copper diamine oxidases (DAOs) and flavoprotein polyamine oxidases (PAOs). In this study, the isolation and characterization of flavin amine oxidases (FAOs) from Brassica juncea (BJFAO) and Arabidopsis (ATFAO1) are reported that were clustered in the same group as polyamine oxidases from maize (MPAO) and barley (BPAO1) and monoamine oxidases from mammalian species. ATFAO1 was temporally and spatially regulated in Arabidopsis and showed distinct expression patterns in response to different stress treatments. To investigate the in vivo function of FAO, transgenic Arabidopsis plants expressing sense, antisense, and double-stranded BJFAO RNAs were generated and those with altered activity of FAOs were selected for further characterization. It was found that the shoot regeneration response in transgenic plants was significantly affected by the modulated PA levels corresponding to FAO activities. Tissues that originated from transgenic plants with down-regulated FAO activity were highly regenerative, while those from transgenic plants with upregulated FAO activity were poorly regenerative. The shoot regeneration capacity in these transgenic plants was related to the levels of individual PAs, suggesting that FAO affects shoot regeneration by regulating cellular PAs. Furthermore, it was found that the effect of FAO activity on shoot regeneration was exerted downstream of the Enhancer of Shoot Regeneration (ESR1) gene, which may function in a branch of the cytokinin signalling pathway.
authors.affiliation: Department of Biological Sciences and Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117543.
authors.forename: Tze Soo
authors.initials: TS
authors.lastname: Lim
authors.forename: Thiruvetipuram Rajam
authors.initials: TR
authors.lastname: Chitra
authors.forename: Ping
authors.initials: P
authors.lastname: Han
authors.forename: Eng Chong
authors.initials: EC
authors.lastname: Pua
authors.forename: Hao
authors.initials: H
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003583:Cytokinins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D009149:Mustard Plant / Q000201:enzymology* / Q000235:genetics; D050891:Oxidoreductases Acting on CH-NH2 Group Donors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018520:Plant Shoots / Q000502:physiology; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000254:growth & development; D011073:Polyamines / Q000378:metabolism; D012038:Regeneration / Q000235:genetics; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; C450147:ESR1 protein, Arabidopsis; D010940:Plant Proteins; D011073:Polyamines; D014157:Transcription Factors; D050891:Oxidoreductases Acting on CH-NH2 Group Donors; C517533:FAO1 protein, Arabidopsis