title: Gene discovery in the Acanthamoeba castellanii genome.
abstract: Acanthamoeba castellanii is a free-living amoeba found in soil, freshwater, and marine environments and an important predator of bacteria. Acanthamoeba castellanii is also an opportunistic pathogen of clinical interest, responsible for several distinct diseases in humans. In order to provide a genomic platform for the study of this ubiquitous and important protist, we generated a sequence survey of approximately 0.5 x coverage of the genome. The data predict that A. castellanii exhibits a greater biosynthetic capacity than the free-living Dictyostelium discoideum and the parasite Entamoeba histolytica, providing an explanation for the ability of A. castellanii to inhabit a diversity of environments. Alginate lyase may provide access to bacteria within biofilms by breaking down the biofilm matrix, and polyhydroxybutyrate depolymerase may facilitate utilization of the bacterial storage compound polyhydroxybutyrate as a food source. Enzymes for the synthesis and breakdown of cellulose were identified, and they likely participate in encystation and excystation as in D. discoideum. Trehalose-6-phosphate synthase is present, suggesting that trehalose plays a role in stress adaptation. Detection and response to a number of stress conditions is likely accomplished with a large set of signal transduction histidine kinases and a set of putative receptor serine/threonine kinases similar to those found in E. histolytica. Serine, cysteine and metalloproteases were identified, some of which are likely involved in pathogenicity.
authors.affiliation: Department of Parasite Genomics, The Institute for Genomic Research, 9712 Medical Center Dr., Rockville, MD 20850, USA. IJAnderson@lbl.gov
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Anderson
authors.forename: Russell F
authors.initials: RF
authors.lastname: Watkins
authors.forename: John
authors.initials: J
authors.lastname: Samuelson
authors.forename: David F
authors.initials: DF
authors.lastname: Spencer
authors.forename: William H
authors.initials: WH
authors.lastname: Majoros
authors.forename: Michael W
authors.initials: MW
authors.lastname: Gray
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: Loftus
mesh_terms: D048248:Acanthamoeba castellanii / Q000201:enzymology / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002480:Cellulase / Q000235:genetics; D003546:Cysteine Endopeptidases / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D004023:Dictyostelium / Q000235:genetics; D004748:Entamoeba histolytica / Q000235:genetics; D017125:Genes, Protozoan; D016678:Genome; D005964:Glucosyltransferases / Q000235:genetics; D000071677:Histidine Kinase; D045726:Metalloproteases / Q000235:genetics; D008969:Molecular Sequence Data; D011133:Polysaccharide-Lyases / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics
chemical_list: D016054:DNA, Protozoan; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D000071677:Histidine Kinase; D002480:Cellulase; D045726:Metalloproteases; D012697:Serine Endopeptidases; D003546:Cysteine Endopeptidases; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase