Genetic diversity of three lgt loci for biosynthesis of lipooligosaccharide (LOS) in Neisseria species

• Published in: Microbiology (Society for General Microbiology) 2002-06, Vol.148 (6), p.1833-1844
• Main Authors: Zhu, Peixuan, Klutch, Michael J, Bash, Margaret C, Tsang, Raymond S. W, Ng, Lai-King, Tsai, Chao-Ming
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Genes, Bacterial - genetics; Genetic Variation - genetics; Genetics; Genotype; Glycosyltransferases - genetics; Lipopolysaccharides - biosynthesis; Microbiology; Molecular Sequence Data; N-Acetylglucosaminyltransferases - genetics; Neisseria gonorrhoeae; Neisseria meningitidis; Neisseria meningitidis - classification; Neisseria meningitidis - genetics; Neisseria meningitidis - growth & development; Neisseria meningitidis - metabolism; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Phylogeny; Polymorphism, Genetic - genetics; Sequence Analysis, DNA
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-148-6-1833

Division of Bacterial, Parasitic and Allergenic Products 1 and Division of Viral Products 2 , Center for Biologics Evaluation and Research, FDA, 8800 Rockville Pike, Bethesda, MD 20892, USA National Microbiology Laboratory, Population and Public Health Branch, Health Canada, Canada 3 Author for correspondence: Peixuan Zhu. Tel: [phone]. Fax: [phone]. e-mail: Zhu{at}cber.fda.gov Lipooligosaccharide (LOS) is a major virulence factor of the pathogenic Neisseria . Nine lgt genes at three chromosomal loci ( lgt-1 , 2 , 3 ) encoding the glycosyltransferases responsible for the biosynthesis of LOS oligosaccharide chains were examined in 26 Neisseria meningitidis , 51 Neisseria gonorrhoeae and 18 commensal Neisseria strains. DNA hybridization, PCR and nucleotide sequence data were compared to previously reported lgt genes. Analysis of the genetic organization of the lgt loci revealed that in N. meningitidis , the lgt-1 and lgt-3 loci were hypervariable genomic regions, whereas the lgt-2 locus was conserved. In N. gonorrhoeae , no variability in the composition or organization of the three lgt loci was observed. lgt genes were detected only in some commensal Neisseria species. The genetic organization of the lgt-1 locus was classified into eight types and the lgt-3 locus was classified into four types. Two types of arrangement at lgt-1 (II and IV) and one type of arrangement at lgt-3 (IV) were novel genetic organizations reported in this study. Based on the three lgt loci, 10 LOS genotypes of N. meningitidis were distinguished. Phylogenetic analysis revealed a gene cluster, lgtH , which separated from the homologous genes lgtB and lgtE . The lgtH and lgtE genes were mutually exclusive and were located at the same position in lgt-1 . The data demonstrated that pathogenic and commensal Neisseria share a common lgt gene pool and horizontal gene transfer appears to contribute to the genetic diversity of the lgt loci in Neisseria . Keywords: Neisseria meningitidis , Neisseria gonorrhoeae , glycosyltransferase, oligosaccharide structure, antigenic variation Abbreviations: LOS, lipooligosaccharide The GenBank accession numbers for the sequences reported in this paper are AF470655 – AF470685 .