title: Response of Dictyostelium discoideum to UV-C and involvement of poly (ADP-ribose) polymerase.
abstract: OBJECTIVE
  Radiation and chemical mutagens are direct DNA-damaging agents and ultraviolet (UV) radiation is frequently used in biological studies. Consequent to ozone depletion, UV-C could become a great challenge to living organisms on earth, in the near future. The present study has focused on the role of poly (ADP-ribose) polymerase (PARP) during UV-C-induced growth and developmental changes in Dictyostelium discoideum, a phylogenetically important unicellular eukaryote.
  
  
  METHODS
  Dictyostelium discoideum cells were exposed to different doses of UV-C and PARP activity, and effects of its inhibition were studied. Expression of developmentally regulated genes yakA, car1, aca, csA, regA, ctnA, ctnB, gp24, hspD and dsn were analysed using semiquantitative RT-PCR.
  
  
  RESULTS
  We report that the D. discoideum cells displayed PARP activation within 2 min of UV-C irradiation and there was increase in NO levels in a dose-dependent manner. UV-C-irradiated cells had impaired growth, delayed or blocked development and delayed germination compared to control cells. In our previous studies we have shown that inhibition of PARP recovered oxidative stress-induced changes in D. discoideum; however, intriguingly PARP inhibition did not correct all defects as effectively in UV-C-irradiated cells. This possibly was due to interplay with increased NO signalling.
  
  
  CONCLUSIONS
  Our results signify that UV-C and oxidative stress affected growth and development in D. discoideum by different mechanisms; these studies could provide major clues to complex mechanisms of growth and development in higher organisms.
authors: Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, 390002, India.
authors: H
authors: H
authors: Mir
authors: T
authors: T
authors: Alex
authors: J
authors: J
authors: Rajawat
authors: A
authors: A
authors: Kadam
authors: R
authors: R
authors: Begum
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D004023:Dictyostelium / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D018507:Gene Expression Regulation, Developmental; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics* / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014466:Ultraviolet Rays
chemical_list: D015815:Cell Adhesion Molecules; C083465:GP24A protein, Dictyostelium discoideum; C083466:GP24B protein, Dictyostelium discoideum; D006360:Heat-Shock Proteins; D015800:Protozoan Proteins; D009569:Nitric Oxide; D011065:Poly(ADP-ribose) Polymerases; D011494:Protein Kinases; C113280:YakA protein, Dictyostelium discoideum; D015105:3',5'-Cyclic-AMP Phosphodiesterases; C112742:regA protein, Dictyostelium