FIG. 2.

Immunoblot analysis of Tpl expression in various E. herbicola strains. Wild-type cells (lanes 1 and 2) and ΔtyrR::kan cells transformed with pTK631 (pSC101replicon bla::tet⁺, lanes 3 and 4) or pTK631 carrying the tyrR allele [tyrR⁺, lanes 5 and 6; tyrR5 (TyrR^{V67A Y72C E201G}), lanes 7 and 8] were grown in basal medium in the presence (+) or absence (−) of additional (0.1%) tyrosine for 13 h at 30°C. Whole-cell extracts were obtained by disrupting cells and separated by SDS–12.5% polyacrylamide gel electrophoresis (32). Following electroblotting onto a polyvinylidene difluoride membrane, immunodetection with anti-Tpl antibodies was carried out as described in the text. The level of Tpl expression was expressed as a percentage relative to the amount of Tpl in the wild-type E. herbicola cells grown under tyrosine-induced conditions.