Article Figures & Data
Figures
- FIG 1
Simplified overview of the O-linked protein glycosylation pathway in Neisseria. The current model of the broad-spectrum O-linked glycosylation pathway expressed by species within the genus Neisseria is shown. OM, outer membrane; IM, inner membrane.
- FIG 2
Protein glycosylation gene variants in meningococcal carriage isolates. An overview of the pgl genes present in the collection is shown. There are two major polymorphisms documented in the pgl locus of strains of Neisseria. The configuration associated with pglG and pglH represents the ancestral form, and the other corresponds to the deleted form. Ancestral and deleted forms are found in combination with both pglB and pglB2 allele variants.
- FIG 3
Phase variation of pgl genes within paired isolates. The variations in the lengths of the phase-variable tracts between all paired isolates (n = 46) are represented by a line for each of the pgl genes. The poly(C) tract in pglG ranges between 8 Cs and 15 Cs for all individuals, with the largest change seen in individuals 6 and 7. The poly(C) tract in pglH/H2 ranges between 9 Cs and 16 Cs for all individuals, with the largest change seen in individual 33. Individuals 28, 29, 32, 34, and 42 lacked the poly(C) tract in pglH (which has only three cytosines in this position). The poly(G) tract in pglA ranges between 9 Gs and 15 Gs, with the largest change seen in individual 2. The poly(G) tract in pgI ranges between 9 Gs and 19 Gs for all individuals. The heptanucleotide phase-variable tract in pglE has between 9 and 59 repeats, with the largest change seen in individuals 8, 23, and 34. The line between the two isolates is horizontal for identical repeat numbers. Pairs where the sequence(s) of one or both isolates was incomplete are indicated at the bottom, along the x axis. Note that a missing line for pglG, pglH, or pglI within an individual indicates the absence of the gene.
- FIG 4
Phase-variable pgl genes. Overviews of the status of phase-variable pgl genes (on/off configurations) for paired isolates (n = 46) (A) and individual isolates (n = 100) (B). The distributions of absent genes, incomplete sequences, on configurations, and off configurations are shown for pglA, pglE, pglI, pglG, and pglH. In addition, pglA and pglH have some alleles without the phase-variable tract and these are constitutively on (No PV tract) (i.e., no phase variation tract).
- FIG 5
Protein glycosylation in ST-192 isolates. Data represent the reactivity of endogenous glycoproteins following immunoblotting with the glycan-specific monoclonal antibodies npg1 (specific for diNAcBAc) (A), npg2 (specific for diNAcBAc-Gal) (B), and npg3 (specific for both diNAcBac and GATDH trisaccharides) (C) and pDAb2 polyclonal antibody (specific for diNAcBac-Glc) (D). The strains used were as follows: lane 1, KS104 (pglC; negative control with no glycan synthesized); lane 2, positive glycan controls, including KS141 (N400 pglA) (A), KS100 (N400) (B), KS142 (N400 pglEon) (C), and KS966 (pglA pglI lct::pglH2SK-03-1035) (D); lanes 3 to 18, N. meningitidis ST-192 isolates from time points A and B as indicated. The pglA, pglE, pglH, and pglI genotype configurations for each isolate are shown below the immunoblots.
- FIG 6
Core genome MLST, pgl genotype, and protein glycosylation phenotype. An overview of phylogenetic relationships together with genotypic and phenotypic results for this strain collection is presented. The genotypic data include the allelic numbers assigned by the PubMLST genome comparator protein glycosylation typing scheme and the on/off configuration of the phase-variable genes. The color codes are shown in the figure legend. Not determined, incomplete sequence, analysis not performed, or not possible to evaluate. All details presented in this figure are listed in Table S1.
Tables
- TABLE 1
Major polymorphism in the pgl locus
Isolate category No. of isolates with indicated status with respect toa: pglH and pglH2 pglB and pglB2 Gene absent 11 0 Allele variant 89 (86 + 3) 100 (70 + 30) Total 100 100 ↵a Values in parentheses represent numbers of isolates with the indicated status with respect to the genes listed in the column headings.
- TABLE 2
Overview of genetic changes in pgl genes in paired meningococcal carriage isolatesa
NEIS no.b Gene Gene product PV tract % of pairsc with genetic differences (n = 46) Mechanism(s) and proportion(s) of pairsd with genetic differences All STs (n = 46) ST-11 (n = 5) ST-53 (n = 4) ST-192 (n = 23) ST-2880 (n = 7) NEIS0568 pglE Glycosyltransferase CAACAAAe 60 PV, 60% PV, 100% PV, 50% PV, 50% PV, 71% NEIS0400 pglH/H2 Glycosyltransferase Poly(C) 44 PV, 44 %; PM, 4% PV, 60% No changef PV, 70%; PM,g,h 9% PV, 14% NEIS0380 pglI O-Acetyltransferase Poly(G) 41 PV, 41 %; PM, 9% PV, 60%; PM,h 40% Gene absent PV, 52% PV, 43%; D,g,h 43% NEIS0401 pglG Putative glycosyltransferase Poly(C) 33 PV, 30 %; R, 4%; PM, 2% PV, 40%; R, 20% PV, 50% PV, 70%; R,h 9%; PM,h 4% No change NEIS0213 pglA Glycosyltransferase Poly(G) 22 PV, 20%; PM, 4%; R, 2%; D, 2% PV, 20%; D,h 20% No change PV, 13% PV, 43%; PM,g,h 29% NEIS0402 pglF Flippase 11 PM, 11% PM, 20% PM,g 75% No change No change NEIS0539 pglO Oligosaccharyltransferase 9 PM, 7%; R, 2% No change PM, 25% PM,g 9%; R, 4.5% No change NEIS0399/NEIS2838 pglB/B2 N-Acetyltransferase/phospho-glycosyltransferase No change No change No change No change No change No change NEIS0397 pglC Aminotransferase No change No change No change No change No change No change NEIS0396 pglD Dehydratase No change No change No change No change No change No change ↵a D, deletion; PM, point mutation; PV, phase variation; R, recombination.
↵b The annotated genes are accessible in Genome Comparator (https://pubmlst.org/).
↵c Data represent pairs with any genetic differences. Pairs from individuals carrying different strains at the two time points were excluded from the analysis.
↵d In some pairs, two or more mechanisms of genetic change were observed.
↵e ST-192 and ST-198 have different repeats as detailed in Table S5.
↵f No PV tract.
↵g The same in all pairs, probably due to recombination.
↵h Close to PV tract.
Supplemental material
- Supplemental file 1 -
Fig. S1 (O-Linked protein glycosylation pathway in Neisseria), S2 and S3 [Alignment of poly(G) tract and flanking sequences in pglA (S2) and pglI (S3)], S4 (Alignment of pglH), S5 (Alignment of heptanucleotide repeat tract and flanking sequences in pglE), and S6 and S7 (Homologous recombination in pglO [S6] and pglG [S7]) and Table S2 (N. gonorrhoeae strains)
PDF, 732K
- Supplemental file 2 -
Table S1 (Correlation between glycosylation genotype and phenotype)
CSV, 34K
- Supplemental file 1 -
