title: Effect of polyamines and synthetic polyamine-analogues on the expression of antizyme (AtoC) and its regulatory genes.
abstract: BACKGROUND
  In bacteria, the biosynthesis of polyamines is modulated at the level of transcription as well as post-translationally. Antizyme (Az) has long been identified as a non-competitive protein inhibitor of polyamine biosynthesis in E. coli. Az was also revealed to be the product of the atoC gene. AtoC is the response regulator of the AtoS-AtoC two-component system and it functions as the positive transcriptional regulator of the atoDAEB operon genes, encoding enzymes involved in short chain fatty acid metabolism. The antizyme is referred to as AtoC/Az, to indicate its dual function as both a transcriptional and post-translational regulator.
  
  
  RESULTS
  The roles of polyamines on the transcription of atoS and atoC genes as well as that of atoDAEB(ato) operon were studied. Polyamine-mediated induction was tested both in atoSC positive and negative E. coli backgrounds by using beta-galactosidase reporter constructs carrying the appropriate promoters patoDAEB, patoS, patoC. In addition, a selection of synthetic polyamine analogues have been synthesized and tested for their effectiveness in inducing the expression of atoC/Az, the product of which plays a pivotal role in the feedback inhibition of putrescine biosynthesis and the transcriptional regulation of the ato operon. The effects of these compounds were also determined on the ato operon expression. The polyamine analogues were also tested for their effect on the activity of ornithine decarboxylase (ODC), the key enzyme of polyamine biosynthesis and on the growth of polyamine-deficient E. coli.
  
  
  CONCLUSIONS
  Polyamines, which have been reported to induce the protein levels of AtoC/Az in E. coli, act at the transcriptional level, since they cause activation of the atoC transcription. In addition, a series of polyamine analogues were studied on the transcription of atoC gene and ODC activity.
authors.affiliation: Laboratory of Biochemistry, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece. filippouyiota@yahoo.gr <filippouyiota@yahoo.gr>
authors.forename: Panagiota S
authors.initials: PS
authors.lastname: Filippou
authors.forename: Efthimia E
authors.initials: EE
authors.lastname: Lioliou
authors.forename: Christos A
authors.initials: CA
authors.lastname: Panagiotidis
authors.forename: Constantinos M
authors.initials: CM
authors.lastname: Athanassopoulos
authors.forename: Thomas
authors.initials: T
authors.lastname: Garnelis
authors.forename: Dionyssios
authors.initials: D
authors.lastname: Papaioannou
authors.forename: Dimitrios A
authors.initials: DA
authors.lastname: Kyriakidis
mesh_terms: D015317:Biogenic Polyamines / Q000096:biosynthesis / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005809:Genes, Regulator; D009876:Operon; D009955:Ornithine Decarboxylase / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D014158:Transcription, Genetic
chemical_list: C505587:AtoC protein, E coli; D015317:Biogenic Polyamines; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D009955:Ornithine Decarboxylase