title: Characterization of nucleases involved in seedling development of cauliflower.
abstract: The ability of cells to control the degradation of their own DNA is a common feature of most living organisms. In plants, extensive hydrolysis of nuclear DNA occurs during different forms of programmed cell death (PCD). In addition to the removal of unwanted cells, the PCD process allows for the remobilization of cellular constituents, including the products of DNA hydrolysis. Although programmed cell death occurs widely during normal development and plant defense responses to pathogens, only one class of deoxyribonucleases, the S1 type, involved in these processes, has been well characterized. Using DNA-SDS-PAGE, we identified the activities of 14 deoxyribonucleases expressed in different organs of cauliflower seeds, seedlings and the flower head. These enzymes represent several classes based on their substrate specificity and ion dependency. In addition to four Zn(2+)-dependent enzymes, we identified five Ca(2+)-dependent, two Mg(2+)-dependent, three Ca(2+)/Mg(2+)-dependent and one nuclease whose activities seem to be independent of any divalent cations. We also identified a set of DNases whose expression seems to be common for different organs and different stages of development, as well as a few highly tissue-specific nucleases. Expression of three nucleases was inducible by drought stress and hydrogen peroxide.
authors.affiliation: Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 89 Umultowska St., 61-614 Poznań, Poland. lesniew@amu.edu.pl
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Leśniewicz
authors.forename: Joanna
authors.initials: J
authors.lastname: Pieńkowska
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Poreba
mesh_terms: D001937:Brassica / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*; D018548:Cotyledon / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D003851:Deoxyribonucleases / Q000096:biosynthesis / Q000378:metabolism*; D055864:Droughts; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009928:Organ Specificity / Q000187:drug effects; D018515:Plant Leaves / Q000201:enzymology / Q000254:growth & development; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: D006861:Hydrogen Peroxide; D003851:Deoxyribonucleases