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Implications of Phase Variation of a Gene (pgtA) Encoding a Pilin Galactosyl Transferase in Gonococcal Pathogenesis

Implications of Phase Variation of a Gene (pgtA) Encoding a Pilin Galactosyl Transferase in... The pilin glycoprotein (PilE) is the main building block of the pilus of Neisseria gonorrhoeae (gonococcus GC). GC pilin is known to carry a disaccharide O-glycan, which has an αGal attached to the O-linked GlcNAc by a 1–3 glycosidic bond. In this report, we describe the cloning and characterization of the GC gene, pilus glycosyl transferase A ( pgtA ), which encodes the galactosyl transferase that catalyzes the synthesis of this Gal–GlcNAc bond of pilin glycan. A homopolymeric tract of Gs (poly-G) is present in the pgtA gene of many GC strains, and this pgtA with poly-G can undergo phase variation (Pv). However, in many other GC, pgtA lacks the poly-G and is expressed constitutively without Pv. Furthermore, by screening a large number of clinical isolates, a significant correlation was observed between the presence of poly-G in pgtA and the dissemination of GC infection. Poly-G was found in pgtA in all (24 out of 24) of the isolates from patients with disseminated gonococcal infection (DGI). In contrast, for the vast majority (20 out of 28) of GC isolated from uncomplicated gonorrhea (UG) patients, pgtA lacked the poly-G. These results indicate that Pv of pgtA is likely to be involved in the conversion of UG to DGI. Neisseria gonorrhoeae pilus DGI poly-G tract glycosyl transferase Footnotes ↵ * Abbreviations used in this paper: DATDH, 2,4-diacetimido-2,4,6-trideoxyhexose; DGI, disseminated gonococcal infection; GC, gonococcus; HPAE-PAD, high performance anion exchange chromatography with pulse amperometric detection; IP, immunoprecipitation; IPTG, isopropyl-β- d -thiogalactopyranoside; LOS, lipooligosaccharide; MC, meningococcus; MS, mass spectrometry; ORF, open reading frame; pgtA , pilus glycosyl transferase A; PID, pelvic inflammatory disease; poly-G/C, homopolymeric tract of Gs or Cs; Pv, phase variation; UG, uncomplicated gonorrhea. Submitted: 5 December 2001 Accepted: 22 May 2002 Revision received 8 April 2002 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Experimental Medicine Rockefeller University Press

Implications of Phase Variation of a Gene (pgtA) Encoding a Pilin Galactosyl Transferase in Gonococcal Pathogenesis

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References (84)

Publisher
Rockefeller University Press
Copyright
© 2002 Rockefeller University Press
ISSN
0022-1007
eISSN
1540-9538
DOI
10.1084/jem.20012022
Publisher site
See Article on Publisher Site

Abstract

The pilin glycoprotein (PilE) is the main building block of the pilus of Neisseria gonorrhoeae (gonococcus GC). GC pilin is known to carry a disaccharide O-glycan, which has an αGal attached to the O-linked GlcNAc by a 1–3 glycosidic bond. In this report, we describe the cloning and characterization of the GC gene, pilus glycosyl transferase A ( pgtA ), which encodes the galactosyl transferase that catalyzes the synthesis of this Gal–GlcNAc bond of pilin glycan. A homopolymeric tract of Gs (poly-G) is present in the pgtA gene of many GC strains, and this pgtA with poly-G can undergo phase variation (Pv). However, in many other GC, pgtA lacks the poly-G and is expressed constitutively without Pv. Furthermore, by screening a large number of clinical isolates, a significant correlation was observed between the presence of poly-G in pgtA and the dissemination of GC infection. Poly-G was found in pgtA in all (24 out of 24) of the isolates from patients with disseminated gonococcal infection (DGI). In contrast, for the vast majority (20 out of 28) of GC isolated from uncomplicated gonorrhea (UG) patients, pgtA lacked the poly-G. These results indicate that Pv of pgtA is likely to be involved in the conversion of UG to DGI. Neisseria gonorrhoeae pilus DGI poly-G tract glycosyl transferase Footnotes ↵ * Abbreviations used in this paper: DATDH, 2,4-diacetimido-2,4,6-trideoxyhexose; DGI, disseminated gonococcal infection; GC, gonococcus; HPAE-PAD, high performance anion exchange chromatography with pulse amperometric detection; IP, immunoprecipitation; IPTG, isopropyl-β- d -thiogalactopyranoside; LOS, lipooligosaccharide; MC, meningococcus; MS, mass spectrometry; ORF, open reading frame; pgtA , pilus glycosyl transferase A; PID, pelvic inflammatory disease; poly-G/C, homopolymeric tract of Gs or Cs; Pv, phase variation; UG, uncomplicated gonorrhea. Submitted: 5 December 2001 Accepted: 22 May 2002 Revision received 8 April 2002

Journal

The Journal of Experimental Medicine – Rockefeller University Press

Published: Jul 15, 2002

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