FIGURE 4.

Regulation of virulence genes by CovRS in GAS. A, effect of the inactivation of CovS (CovS^M) and CovR (ΔCovR) on the transcription levels of hasA, sk, and sen genes. The levels of each specific transcript in the total mRNA of the indicated cell lines, relative to expression of each of the genes in AP53/CovS^M (WT-AP53) cells arbitrarily set at 100%, are shown. Both gapdh and mutS were used as loading controls, with the results of A not differing with either housekeeping gene. B, amount of HA-containing capsule in AP53/CovS^M (WT-AP53), AP53/CovS^WT, AP53/CovS^M/ΔCovR, NS931/CovS^WT (WT-NS931), and NS931/CovS^M. C, activation of hPg by mid-log phase culture supernatants (A_{600 nm} ∼0.6) of the cell lines indicated on the graph.