TABLE 1

Effects of termination, tylosin, leader peptide, and pausing on yxjB expression

TABLE 1
  • a β-Galactosidase activity was measured during the mid-exponential phase (Mid-exp), the late exponential phase (Late-exp), the transition between exponential and stationary phase (Transition), and the stationary phase (Stationary). Cells were grown in the absence or presence of the indicated concentration (in micrograms per milliliter) of tylosin (Tyl) or erythromycin (Ery). Each experiment was performed at least 3 times. Values are given in Miller units ± standard deviations.

  • b yxjB-lacZ TXN, PyxjB-yxjB-lacZ transcriptional fusion; yxjB-lacZ TXN T-mut, PyxjB-yxjB-lacZ transcriptional fusion with G71A and G72A terminator mutations; yxjB′-′lacZ TLN, PyxjB-yxjB′-′lacZ translational fusion; LP′-′lacZ TLN, PyxjB-LP′-′lacZ translational fusion; yxjB′-′lacZ TLN LP-mut, PyxjB-yxjB′-′lacZ translational fusion with the LP ATG start codon mutated to ACG; yxjB′-′lacZ TLN LP-AYA, PyxjB-yxjB′-′lacZ translational fusion with the LP RYR ribosome stalling motif mutated to AYA; yxjB′-′lacZ TLN P-mut, PyxjB-yxjB′-′lacZ translational fusion with the T131A pause site mutation.

  • c No measurable expression was observed when cells were grown in the presence of erythromycin at 0.0125, 0.025, or 0.05 μg/ml. Data are shown for the highest concentration only.