Table 3.
LcrVS324 blocks type III secretion of YopH in Y. pestis calcium-blind mutants with yscFD28A and yscFD46A mutations
| yscF allele |
Y. pestis (ΔyopE/sycE) % type III secretion ([S]/[S+P])a |
|||
|---|---|---|---|---|
| No plasmid |
plcrVS324 |
|||
| YopH | LcrV | YopH | LcrV | |
| yscF | 45.2 | 42.7 | 2.9 | 5.3 |
| yscFD28A | 44.9 | 39.8 | 4.5 | 18.2 |
| yscFD46A | 45.8 | 29.1 | 4.4 | 15.3 |
| yscFD28A,D46A | 47.3 | 45.8 | 2.2 | 9.3 |
| yscFD77A | 0.9 | 1.1 | 3.3 | 4.9 |
a
Type III secretion of Y. pestis strains with or without plcrVS324 was measured after 3 h of growth in cultures that were grown in media with chelated calcium ions at 37°C. Following centrifugation, the extracellular medium was separated into the supernatant (S) and the bacterial pellet (P), and proteins in both fractions were precipitated with trichloroacetic acid and analyzed by immunoblotting with specific antibodies against the type III secretion substrates YopH and LcrV. Secretion was quantified by calculating the percent amount of secreted protein [S] compared to protein in both the medium and the pellet [S+P].