TABLE 3.

β-Galactosidase assays using the MudJ lac operon fusion vector as transcriptional reportera

Strain backgroundsrfBSTM2314 (cheV)STM3152 (mcpB)STM3216 (mcpC)aerflgKfliB
Wild type13 ± 2120 ± 3646 ± 1575 ± 3979 ± 3671 ± 1.447 ± 1.6
ΔflhDC <1 ± 0.17.7 ± 4.61.7 ± 0.72.9 ± 1.32.1 ± 0.6<1 ± 0.1<1 ± 0.1
fliA 11 ± 2.12.2 ± 1.42.2 ± 1.43.2 ± 1.81.5 ± 0.517 ± 1.427 ± 1.0
Δhin-5717::FCF35 ± 9.935 ± 9.992 ± 30100 ± 33
Δhin-5718::FCF11 ± 1411 ± 1462 ± 38120 ± 9
Δhin-5717::FCF ΔflhD2039 <1 ± 1<1 ± 13.8 ± 1.51.9 ± 0.8
Δhin-5717::FCF fliA 1.9 ± 0.41.9 ± 0.43.4 ± 1.31.9 ± 0.4
  • a The expression of srfB::MudJ, flgK::MudJ and fliB::MudJ fusions were assayed in strains defective in either fliA28) or FlhDC compared to expression in the isogenic wild-type strain. The fliA allele used in these assays was fliA5999(R91C, L207P) and carries two point mutations that make this nonpolar mutant form of σ28 defective in binding both the −35 (L207P) and −10 (R91C) regions of flagellar promoters. The expression of cheV::MudJ, mcpB::MudJ, mcpC::MudJ, and aer::MudJ fusions was assayed in strains defective in either fliA28) or FlhDC compared to expression in the isogenic wild-type strain and in strains locked in either the fliC ON fljB OFFhin-5717::FCF) or fliC OFF fliB ONhin-5718::FCF) state of flagellar phase variation to determine if these genes were affected by flagellar phase variation.