F. Western blot analysis of the production of chromosomally-encoded VcdP::SPA, corresponding to the same growth conditions as the Northern blot in (D). The SPA epitope contains the 3×FLAG and the calmodulin binding peptide sequences separated by a TEV protease cleavage site (Zeghouf et al, 2004). Therefore, anti-Flag antibody was used to examine the levels of VcdP. RNAP served as a loading control. 