Table 4.
Potential pathogenic genes in Ehrlichia sp. HF, E. chaffeensis, E. muris subsp. muris, and E. muris subsp. eauclairensis
| Organisms1 | EHF | ECH | EMU | EmCRT |
|---|---|---|---|---|
| Outer Membrane Proteins: | ||||
| Omp-1/P28 family proteins | 23 | 22 | 20 | 20 |
| Omp85 | + | + | + | + |
| OmpH | + | + | + | + |
| OmpA family protein | + | + | + | + |
| EtpE | + | + | + | + |
| Type IV Secretion System: | ||||
| VirB1/B5 | - | - | - | - |
| VirB2 | + (5) | + (4) | + (4) | + (5) |
| VirB3 | + | + | + | + |
| VirB4 | + (2) | + (2) | + (2) | + (2) |
| VirB6 | + (4) | + (4) | + (4) | + (4) |
| VirB7 | + | + | + | + |
| VirB8 | + (2) | + (2) | + (2) | + (2) |
| VirB9 | + (2) | + (2) | + (2) | + (2) |
| VirB10/B11/D4 | + | + | + | + |
| Putative T4SS Effectors: | ||||
| Etf-1 | + | + | + | + |
| Etf-22 | ± | + | ± | ± |
| Etf-3 | + | + | + | + |
| Type I Secretion System3 | + | + | + | + |
| Twin-arginine Translocation (TAT) Pathway4 | + | + | + | + |
| TRP Proteins | ||||
| TRP32 | + (94 aa) | + (198 aa) | + (112 aa) | + (105 aa) |
| TRP47 | + (255 aa) | + (316 aa) | + (228 aa) | + (252 aa) |
| TRP120 | + (584 aa) | + (548 aa) | + (1288 aa) | +5 |
| Ankyrin-repeat domain proteins | 5 | 5 | 5 | 5 |
| Two-Component Regulatory Systems: | ||||
| PleC/PleD | + | + | + | + |
| NtrY/NtrX | + | + | + | + |
| CckA/CtrA | + | + | ±6 | + |
1Abbreviations: EHF, Ehrlichia sp. HF; EMU, E. muris subsp. muris AS145; ECH, E. chaffeensis Arkansas; EmCRT, E. muris subsp. eauclairensis Wisconsin. Numbers inside parentheses indicate the copy number of the gene; or else, only a single copy exists. +, genes present; -, homolog of the gene not identified based on Blast searches.
2In addition to Etf-2 (ECH_0261, 264 aa), E. chaffeensis encodes six paralogs of Etf-2 with protein sizes range from 190 ~ 350 AA (ECH_0243, 293 aa; ECH_0246, 285 aa; ECH_0247, 316 aa; ECH_0253, 189 aa; ECH_0255, 352 aa; and ECH_0257, 226 aa). However, only low homologies (26 ~ 32% AA sequence identity) to E. chaffeensis Etf-2 were identified in other Ehrlichia spp. (indicated by ±)
3Type I Secretion System is consisting of an outer membrane channel protein TolC, a membrane fusion protein HlyD, and an ATPase HlyB. All are present in these Ehrlichia spp
4Both twin-arginine translocase subunits TatA and TatC were identified in all Ehrlichia spp
5Tblastn search indicates that that the homolog of E. chaffeensis TRP120 in E. muris subsp. eauclairensis Wisconsin is split into two pseudogenes (EMUCRT_0995 and EMUCRT_0731) present in two separate contigs (NZ_LANU01000002 and NZ_LANU01000003) of the incomplete genome sequences
6Gene encoding CtrA protein was identified in E. muris subsp. muris AS145 genome. However, cckA gene is annotated as a pseudogene due to an internal deletion, causing frameshift at 1,123 bp