Fig. 4.

EIIA^Ntr-mediated change in AHAS expression depends on TrkA. (A) AHAS activity assays. Cells of strains MG1655, CR301 (ptsN), CR302 (ptsN TrkA), and EB101 (trkA) grown in LB were harvested, washed, and resuspended in K₀ minimal medium containing 0.5% glucose (filled bars) and K₂₀ minimal medium containing 0.5% glucose (open bars). Subsequently, cells were allowed to grow to midlogarithmic phase, and the specific activities of AHAS were measured as described in Materials and Methods. (B) Measurement of the ilvBN transcript by RT-PCR, which was carried out as described previously (15). (C) Primer extension analysis of the ilvBN transcript. RNA was prepared from the indicated cells grown to midlogarithmic phase in M9 minimal medium containing 0.5% glucose by using an RNeasy mini kit (Qiagen), and primer extension assays were carried out as described previously (5).