realized in has disposition at some time artificially mutated Brucella attenuated disposition mouse - Brucella interaction Brucella ftcR mutant MUTATION: FtcR is required in B melitensis 16M for the transcription of the fliF gene during vegetative and intracellular growth, and for the production of the two structural flagellar components FlgE and FliC during vegetative growth. A ftcR mutant has the same virulence phenotype as previously found with structural flagellar mutants. In HeLa cells and bovine macrophages, no attenuation of the ftcR mutant was observed compared to the WT parental strain. In BALB/c mice, the ftcR mutant was not attenuated after 1 week of infection but was attenuated after 4 weeks of infection. FtcR acts as a flagellar master regulator in B melitensis and perhaps in other related alpha-proteobacteria [Léonard et al., 2007]. See PMID:17056750