HmbR, a Hemoglobin-Binding Outer Membrane Protein of Neisseria meningitidis, Undergoes Phase Variation

ABSTRACT Neisseria meningitidis uses hemoglobin (Hb) as an iron source via two TonB-dependent outer membrane receptors, HmbR and HpuB. Analysis of 25 epidemiologically unrelated clinical isolates from serogroups A, B, C, and Y revealed that 64% strains possessed both Hb receptor genes. Examination of the hmbR expression pattern in strains in which the hpuB gene was genetically inactivated revealed two distinct Hb utilization phenotypes. Five strains retained the ability to grow as a confluent lawn, while seven grew only as single colonies around Hb discs. The single-colony phenotype observed for some hpuB mutants is suggestive of phase variation of hmbR. The length of the poly(G) tract starting at position +1164 of hmbR absolutely correlated with the two Hb utilization phenotypes. All five strains that grew as confluent lawns around Hb discs possessed either 9 or 12 consecutive G residues. All seven strains that grew as single colonies around Hb discs had poly(G) tracts of a length other than 9 or 12. These single-colony variants that arose around the Hb discs had poly(G) tracts with either 9 or 12 consecutive G residues restoring thehmbR reading frame. Inactivation of hmbR in these strains resulted in a loss of Hb utilization, demonstrating that the change in the hmbR gene was responsible for the phenotypic switch. The switching rates from hmbR phase off to phase on were ∼5 × 10−4 in four serogroup C strains, 2 × 10−2 in the serogroup A isolate, and 7 × 10−6 in the serogroup B isolate.

[1]  D. Morton,et al.  hgpB, a Gene Encoding a Second Haemophilus influenzae Hemoglobin- and Hemoglobin-Haptoglobin-Binding Protein , 1998, Infection and Immunity.

[2]  Alex van Belkum,et al.  Short-Sequence DNA Repeats in Prokaryotic Genomes , 1998, Microbiology and Molecular Biology Reviews.

[3]  C. Elkins,et al.  Phase Variation of Hemoglobin Utilization inNeisseria gonorrhoeae , 1998, Infection and Immunity.

[4]  J. Peden,et al.  Simple sequence repeats in the Helicobacter pylori genome , 1998, Molecular microbiology.

[5]  B. Roe,et al.  Molecular characterization of hpuAB, the haemoglobin–haptoglobin‐utilization operon of Neisseria meningitidis , 1997, Molecular microbiology.

[6]  N. Srinivasan,et al.  Neisseria meningitidis tonB, exbB, and exbD genes: Ton-dependent utilization of protein-bound iron in Neisseriae , 1997, Journal of bacteriology.

[7]  L. Brammer,et al.  Influenza surveillance--United States, 1992-93 and 1993-94. , 1997, MMWR. CDC surveillance summaries : Morbidity and mortality weekly report. CDC surveillance summaries.

[8]  J. H. Carlson,et al.  Promoter strength influences phase variation of neisserial opa genes , 1997, Molecular microbiology.

[9]  C. Elkins,et al.  Identification and purification of a hemoglobin-binding outer membrane protein from Neisseria gonorrhoeae , 1996, Infection and immunity.

[10]  R. Fleischmann,et al.  DNA repeats identify novel virulence genes in Haemophilus influenzae. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[11]  V. Hwa,et al.  HmbR outer membrane receptors of pathogenic Neisseria spp.: iron-regulated, hemoglobin-binding proteins with a high level of primary structure conservation , 1996, Journal of bacteriology.

[12]  S. Hammerschmidt,et al.  Capsule phase variation in Neisseria meningitidis serogroup B by slipped‐strand mispairing in the polysialyltransferase gene (siaD): correlation with bacterial invasion and the outbreak of meningococcal disease , 1996, Molecular microbiology.

[13]  D. Hood,et al.  Tetrameric repeat units associated with virulence factor phase variation in Haemophilus also occur in Neisseria spp. and Moraxella catarrhalis. , 1996, FEMS microbiology letters.

[14]  E. Gotschlich,et al.  Variation of gonococcal lipooligosaccharide structure is due to alterations in poly-G tracts in lgt genes encoding glycosyl transferases , 1996, The Journal of experimental medicine.

[15]  D. Hood,et al.  Molecular analysis of a locus for the biosynthesis and phase‐variable expression of the lacto‐N‐neotetraose terminal lipopolysaccharide structure in Neisseria meningitidis , 1995, Molecular microbiology.

[16]  B. Plikaytis,et al.  Epidemiology and prevention of meningococcal disease , 1995, The Pediatric infectious disease journal.

[17]  Ende,et al.  Variable expression of class 1 outer membrane protein in Neisseria meningitidis is caused by variation in the spacing between the -10 and -35 regions of the promoter , 1995, Journal of bacteriology.

[18]  D. Dyer,et al.  Identification of an iron-regulated outer membrane protein of Neisseria meningitidis involved in the utilization of hemoglobin complexed to haptoglobin , 1995, Journal of bacteriology.

[19]  P. Dumas,et al.  Evaluation of transferrin-binding protein 2 within the transferrin-binding protein complex as a potential antigen for future meningococcal vaccines , 1995, Infection and immunity.

[20]  V. Hwa,et al.  The Neisseria meningitidis haemoglobin receptor: its role in iron utilization and virulence , 1995, Molecular microbiology.

[21]  J. Hockin,et al.  The changing epidemiology of invasive meningococcal disease in Canada, 1985 through 1992. Emergence of a virulent clone of Neisseria meningitidis. , 1995, JAMA.

[22]  P. Sparling,et al.  Iron piracy: acquisition of transferrin‐bound iron by bacterial pathogens , 1994, Molecular microbiology.

[23]  P. Sneath,et al.  A numerical phenotypic taxonomic study of the genus Neisseria. , 1994, Microbiology.

[24]  A. Smith,et al.  Invasive disease caused by Neisseria meningitidis relatively resistant to penicillin in North Carolina. , 1994, The Journal of infectious diseases.

[25]  L. Irons,et al.  Immune responses in humans and animals to meningococcal transferrin-binding proteins: implications for vaccine design , 1994, Infection and immunity.

[26]  M. Achtman,et al.  Variable expression of the Opc outer membrane protein in Neisseria meningitidis is caused by size variation of a promoter containing poly‐cytidine , 1994, Molecular microbiology.

[27]  C. Elkins,et al.  Vaccines for bacterial sexually transmitted infections: a realistic goal? , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[28]  E. Ford,et al.  Surveillance for diabetes mellitus--United States, 1980-1989; and Laboratory-based surveillance for meningococcal disease in selected areas--United States, 1989-1991 , 1993 .

[29]  L S Geiss,et al.  Surveillance for diabetes mellitus--United States, 1980-1989. , 1993, MMWR. CDC surveillance summaries : Morbidity and mortality weekly report. CDC surveillance summaries.

[30]  B. C. Lee,et al.  Identification of an outer-membrane haemoglobin-binding protein in Neisseria meningitidis. , 1992, Journal of general microbiology.

[31]  D. Maclaren,et al.  Transferrins and heme-compounds as iron sources for pathogenic bacteria. , 1992, Critical reviews in microbiology.

[32]  S. Normark,et al.  Phase variation of gonococcal pili by frameshift mutation in pilC, a novel gene for pilus assembly. , 1991, The EMBO journal.

[33]  J. Cannon,et al.  Variation in expression of class 1 and class 5 outer membrane proteins during nasopharyngeal carriage of Neisseria meningitidis , 1990, Infection and immunity.

[34]  A. Schryvers,et al.  Comparison of the abilities of different protein sources of iron to enhance Neisseria meningitidis infection in mice , 1989, Infection and immunity.

[35]  S. Morrison,et al.  Expression and phase variation of gonococcal P.11 genes in Escherichia coli involves ribosomal frameshifting and slipped‐strand mispairing , 1989, Molecular microbiology.

[36]  T. Meyer,et al.  Genetic mechanisms and biological implications of phase variation in pathogenic neisseriae , 1989, Clinical Microbiology Reviews.

[37]  M. Koomey,et al.  Phase variation of gonococcal protein II: Regulation of gene expression by slipped-strand mispairing of a repetitive DNA sequence , 1989, Cell.

[38]  A. Schryvers,et al.  Identification and characterization of the transferrin receptor from Neisseria meningitidis , 1988, Molecular microbiology.

[39]  D. Barritt,et al.  Reversible phase variation of expression of Neisseria meningitidis class 5 outer membrane proteins and their relationship to gonococcal proteins II , 1988, Infection and immunity.

[40]  T. Meyer,et al.  Common mechanism controlling phase and antigenic variation in pathogenic Neisseriae , 1987, Molecular microbiology.

[41]  P. Sparling,et al.  Effects of serum carrier proteins on the growth of pathogenic neisseriae with heme-bound iron , 1987, Infection and immunity.

[42]  G. Gutman,et al.  Slipped-strand mispairing: a major mechanism for DNA sequence evolution. , 1987, Molecular biology and evolution.

[43]  C. Latorre,et al.  Neisseria meningitidis strains with decreased susceptibility to penicillin , 1987, The Pediatric infectious disease journal.

[44]  G. Murphy,et al.  Distribution of specific DNA sequences among pathogenic and commensal Neisseria species , 1987, Infection and immunity.

[45]  E. Tikhomirov.  Meningococcal meningitis: global situation and control measures. , 1987, World health statistics quarterly. Rapport trimestriel de statistiques sanitaires mondiales.

[46]  T. Meyer,et al.  Opacity genes in Neisseria gonorrhoeae: Control of phase and antigenic variation , 1986, Cell.

[47]  G. Sensabaugh,et al.  Genetic relationships among Neisseria species assessed by comparative enzyme electrophoresis. , 1985, Journal of general microbiology.

[48]  J. Sambrook,et al.  Molecular Cloning: A Laboratory Manual , 2001 .

[49]  T. Meyer,et al.  Pilus expression in neisseria gonorrhoeae involves chromosomal rearrangement , 1982, Cell.

[50]  P. Mickelsen,et al.  Ability of Neisseria gonorrhoeae, Neisseria meningitidis, and commensal Neisseria species to obtain iron from transferrin and iron compounds , 1981, Infection and immunity.

[51]  E. Gotschlich,et al.  Kinetics of antibody production to group A and group C meningococcal polysaccharide vaccines administered during the first six years of life: prospects for routine immunization of infants and children. , 1979, The Journal of infectious diseases.

[52]  M. Simon,et al.  Regulation of gene expression by site-specific inversion , 1978, Cell.