title: Plant plasma membrane-bound staphylococcal-like DNases as a novel class of eukaryotic nucleases.
abstract: BACKGROUND
  The activity of degradative nucleases responsible for genomic DNA digestion has been observed in all kingdoms of life. It is believed that the main function of DNA degradation occurring during plant programmed cell death is redistribution of nucleic acid derived products such as nitrogen, phosphorus and nucleotide bases. Plant degradative nucleases that have been studied so far belong mainly to the S1-type family and were identified in cellular compartments containing nucleic acids or in the organelles where they are stored before final application. However, the explanation of how degraded DNA components are exported from the dying cells for further reutilization remains open.
  
  
  RESULTS
  Bioinformatic and experimental data presented in this paper indicate that two Arabidopsis staphylococcal-like nucleases, named CAN1 and CAN2, are anchored to the cell membrane via N-terminal myristoylation and palmitoylation modifications. Both proteins possess a unique hybrid structure in their catalytic domain consisting of staphylococcal nuclease-like and tRNA synthetase anticodon binding-like motifs. They are neutral, Ca2+-dependent nucleaces showing a different specificity toward the ssDNA, dsDNA and RNA substrates. A study of microarray experiments and endogenous nuclease activity revealed that expression of CAN1 gene correlates with different forms of programmed cell death, while the CAN2 gene is constitutively expressed.
  
  
  CONCLUSIONS
  In this paper we present evidence showing that two plant staphylococcal-like nucleases belong to a new, as yet unidentified class of eukaryotic nucleases, characterized by unique plasma membrane localization. The identification of this class of nucleases indicates that plant cells possess additional, so far uncharacterized, mechanisms responsible for DNA and RNA degradation. The potential functions of these nucleases in relation to their unique intracellular location are discussed.
authors.affiliation: Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, 89 Umultowska St, Poznan 61-614, Poland. lesniew@amu.edu.pl
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Leśniewicz
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Poręba
authors.forename: Michalina
authors.initials: M
authors.lastname: Smolarkiewicz
authors.forename: Natalia
authors.initials: N
authors.lastname: Wolff
authors.forename: Sławoj
authors.initials: S
authors.lastname: Stanisławski
authors.forename: Przemysław
authors.initials: P
authors.lastname: Wojtaszek
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis; D002462:Cell Membrane / Q000201:enzymology*; D003851:Deoxyribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000201:enzymology*; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions / Q000235:genetics; D054878:Lipoylation; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D018515:Plant Leaves / Q000201:enzymology / Q000254:growth & development; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011523:Protoplasts / Q000201:enzymology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology; D052584:Xylem / Q000201:enzymology / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; D011993:Recombinant Fusion Proteins; C580759:CAN1 protein, Arabidopsis; C580760:CAN2 protein, Arabidopsis; D003851:Deoxyribonucleases