FIG. 1.

TraR expression in a T7 system in A. tumefaciens. (A) TraR protein abundance in PtetR-traR and PT7-traR strains. Strains WCF47(pCF218)(pCF372) and KYC55(pJZ372)(pJZ384)(pJZ410) were cultured overnight in the presence of 100 nM OOHL, diluted serially in fourfold increments, size fractionated by SDS-PAGE, and immunodetected with rabbit polyclonal antiserum. (B) Pulse-labeling of TraR. Strain KYC55(pJZ372)(pJZ384)(pJZ410) was cultured to mid-logarithmic phase in AT medium in the absence or presence of 100 nM OOHL at 28°C, incubated with rifampin for 30 min, and then pulse-labeled with [³⁵S]methionine for 5 min. The cultures were then chased with nonradiolabeled methionine and terminated by freezing at −80°C at various intervals as indicated. Cleared lysates were size fractionated by SDS-PAGE, and gels were analyzed with a Storm B840 PhosphorImager (Molecular Dynamics).