title: Characterization of the Legionella pneumophila gene ligA.
abstract: Legionella pneumophila is a bacterial pathogen that resides and multiplies in macrophages as well as in its natural aquatic hosts, the protozoa. Different bacterial factors contribute to pathogenicity and accompanying eukaryotic intracellular events. Sequencing of mip flanking regions revealed a gene of 2610 bp, ligA, that has no significant similarity to any of the genes identified previously. Epidemiological studies indicate that this gene is present in Legionella pneumophila, the species most often associated with cases of the Legionnaires' disease, but not in Legionella species other than L. pneumophila. The isogenic ligA deletion mutant was resistant to NaCl, and showed decreased cytotoxicity to human monocytes and decreased hemolytic activity to red blood cells. However, the most prominent effect of the L. pneumophila ligA mutant strain LEPF1 was the nearly completely reduced replication within the natural host Acanthamoeba castellanii. Since this gene is L. pneumophila specific and regulates numerous bacterial properties we designated this gene ligA for Legionella pneumophila infectivity gene A.
authors.affiliation: Department of Medical Microbiology and Hygiene, University of Ulm, Germany.
authors.forename: P S
authors.initials: PS
authors.lastname: Fettes
authors.forename: M
authors.initials: M
authors.lastname: Susa
authors.forename: J
authors.initials: J
authors.lastname: Hacker
authors.forename: R
authors.initials: R
authors.lastname: Marre
mesh_terms: D000048:Acanthamoeba / Q000382:microbiology; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D015152:Blotting, Northern; D015139:Blotting, Southern; D002460:Cell Line; D006461:Hemolysis; D006801:Humans; D020104:Immunophilins / Q000235:genetics; D016952:Legionella pneumophila / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D008264:Macrophages / Q000166:cytology / Q000382:microbiology; D008565:Membrane Proteins / Q000235:genetics; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D019696:Peptidylprolyl Isomerase; D016133:Polymerase Chain Reaction; D017384:Sequence Deletion; D012756:Sheep; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D020104:Immunophilins; C512922:Mip protein, Legionella pneumophila; D019696:Peptidylprolyl Isomerase