TABLE 3.

Multiple regulatory mechanisms modulate transcriptional output of ilvB

GenotypeMediumaActive regulatory factor(s)bDoubling time (min)cCopies of ilvB transcriptd
ilvBp+TSSCcpA, T box, CodY56.8 ± 2.8106.6 ± 11.0
ilvBpcre1TSST box, CodY48.0 ± 1.017.2 ± 2.0
ilvBp4TSSCcpA, T box58.1 ± 5.9146.8 ± 12.8
ilvBpΔT2TSSCcpA, CodY64.4 ± 3.2787.9 ± 106.7
ilvBp4 ilvBpΔT2TSSCcpA70.9 ± 2.1977.3 ± 173.1
codY::(erm::spc)TSSCcpA, T box58.0 ± 2.6232.2 ± 56.2
ilvBpΔT2 codY::(erm::spc)TSSCcpA101.4 ± 7.2865.2 ± 187.7
ilvBp+TSS-N + glutamateCcpA, TnrA, T box, CodY119.2 ± 15.019.3 ± 4.5
ilvBpΔTBSTSS-N + glutamateCcpA, T box, CodY85.6 ± 5.2100.6 ± 17.8
tnrA62::(Tn917 erm)TSS-N + glutamateCcpA, T box, CodY95.4 ± 1.674.2 ± 8.2
ilvBp+TSS-N + glutamate + NH4+CcpA, T box, CodY42.8 ± 3.4107.0 ± 14.6
ilvBpΔTBSTSS-N + glutamate + NH4+CcpA, T box, CodY44.6 ± 6.0102.2 ± 24.6
tnrA62::(Tn917 erm)TSS-N + glutamate + NH4+CcpA, T box, CodY42.6 ± 4.499.8 ± 19.7
ilvBp+TSS + ILVCcpA, T box, CodY52.8 ± 2.866.0 ± 17.8
ilvBp4TSS + ILVCcpA, T box58.6 ± 2.8145.9 ± 19.7
codY::(erm::spc)TSS + ILVCcpA, T box55.8 ± 1.275.3 ± 15.2
ilvBpΔT2TSS + ILVCcpA, CodY65.0 ± 0.8911.1 ± 39.8
ilvBp4 ilvBpΔT2TSS + ILVCcpA79.1 ± 4.71138.3 ± 236.0
ilvBpcre1 codY::(erm::spc)TSS + ILVT box56.4 ± 0.928.0 ± 3.4
ilvBp+TSS + 16 AACcpA, T box, CodY31.0 ± 1.03.1 ± 0.7
ilvBpcre1TSS + 16 AAT box, CodY31.1 ± 2.00.9 ± 0.2
ccpA::[(Tn917-lacZ)::spc]TSS + 16 AAT box, CodY31.2 ± 2.80.5 ± 0.1
ilvBpcre1 ilvBp4TSS + 16 AAT box, CodY(w)30.0 ± 0.112.6 ± 2.7
ilvBp4TSS + 16 AACcpA, T box, CodY(w)29.4 ± 1.286.0 ± 6.8
ilvBpΔT2TSS + 16 AACcpA, CodY30.3 ± 3.159.9 ± 15.9
ilvBp4 ilvBpΔT2TSS + 16 AACcpA CodY(w)35.5 ± 4.7585.1 ± 165.0
codY::(erm::spc)TSS + 16 AACcpA, T box37.9 ± 1.8245.2 ± 22.1
ilvBpΔT2 codY::(erm::spc)TSS + 16 AACcpA48.9 ± 3.3829.5 ± 343.3
  • a TSS, minimal glucose medium with NH4Cl as nitrogen source; TSS-N, TSS without NH4Cl; 16 AA, an amino acid mixture previously shown to fully activate CodY (3).

  • b CodY(w), denotes possible weak interaction of CodY with the ilvB promoter region.

  • c Data represent averages for at least two biological replicates ± standard errors of the means.

  • d Copies of ilvB transcript per 106 copies of rrnA transcript (mean ± standard error of the mean for at least two biological replicates). Student's t test was used to determine statistical significance (P < 0.05).