Fig 2.

Reduced synthesis of SecA in L22 mutant strains leads to a dramatic loss of Ag43 transcripts. (A) MG1655 (WT) and MG1655 derivatives containing the indicated mutation were grown at 37°C, and the steady-state level of Ag43 was measured by Western blotting using an antiserum raised against the Ag43 β domain. The cells shown in lane 6 were transformed with plasmid pMF8 (encoding secM-secA). pro, proAg43; β, Ag43 β domain. (B) Autoaggregation of the strains shown in panel A in static cultures. (C) Quantitative RT-PCR analysis of the level of the Ag43 gene, secA, and tnaA transcripts in MNY15 relative to MG1655. (D) The steady-state level of SecA in MG1655 (WT) and MG1655 derivatives containing the indicated mutation was measured by Western blotting. The cells shown in the last lane were transformed with plasmid pMF8.